Assembling Finishing

13 Oct 2011 at 22:20

captain

How to build a boat

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The process of assembling the structural members of a boat may now be considered. First, however (unless modern full-sized boat patterns are used), the water lines and sections at each frame must be laid down full size. This is done on the floor of the amateur builder’s shed or loft and chalk marks are usually employed for the purpose, these being often done over with black lead to prevent rubbing out. The lines are taken from the designer’s plans, including the half-breadth body and sheer plans, but are made full size, all proportions being duly observed. The sections when transferred to the floor will indicate the sectional form at various stations to be regularly measured off along the line of the keel. These should be numbered for convenience.

It should be noted whether the lines of the design relate to the outside of the frame or to the actual water surface of the boat. If the latter, the thickness of the planking must be deducted all along the section lines in order to obtain proper form for the frame.
If the boat is to be built with fixed molds, after laying down the lines we must next determine the form of the molds. At least five such molds are required between the stem and stern post and it will often be found advantageous to use not less than eight molds for boats of small size. A series of twelve molds is frequently used for a small launch.

The form of each mold is obtained from the full-size sections. A single board of sufficient width is used to form one-half of the mold. A duplicate of this being made, the two are placed together to form the complete mold.
To obtain the form of the half section on the board used for the purpose, nails may be laid down with their heads on the section line and the bodies at right angles thereto, the board being then gently laid down upon the nails and tapped with a hammer or pressed upon them. An imprint of the nail heads will thus be made on the under side of the board and it will then be an easy matter to reproduce the form of the half section on the board by means of a batten sprung through the continuous im- prints of the nail heads.

The half of the mold is then cut along the lines indicated. The vertical section lines having been noted, the duplicate half is cut and the two may be joined in the manner indicated in the illustration, with a cross-pawl or horizontal piece of timber at the top.

The rest of the molds are made in a similar way, until the entire series is complete. They are then ready to be assembled on the keel, and we may proceed to prepare the keel.
To support the keel a two-inch plank should be set up on end and blocked securely. The upper edge must be cut or trimmed to correspond with the design for the sweep of the keel. This supporting plank forms no part of the boat structure, but is simply a convenient foundation for the work. If this support is adjusted in such a manner as to bring the intended water line of the boat horizontal with reference to the floor of the shed or loft, it will be found a great convenience to the builder.
A pattern for the stem is taken from the floor in the same way as the form of the molds is secured, and it may be noted here that while the molds are on the floor, the height of the deck line, if any, and the load water line should be marked on them.

The keel, stem and stern posts should now be prepared according to the dimensions required and must be rabbeted to admit the edge of the garboard strake, or first range or strake of planks laid on the bottom of the hull next to the keel, and its ends at the stern and stem. They are then erected in turn on the keel support and the stem and stern posts are secured to the keel by means of chocks and fastenings through and through.
For the stem a white oak plank may be used, cut to shape of the pattern. A center line should be scratched along its face and also another line on each side of this to show width of the face when finished. The thickness of the stem usually tapers to the point where it joins the keel. Position of the load water line taken from the body plan should be scratched across the face of the stern.

The stem and stern knees should be cut as shown on the plan and bolted to the stern with Y$ inch galvanized bolts, care being taken to set the bolts at cross angles across the scarf to draw the stem and knee together. It the boat is to be fitted with the old form of stern the deadwood and shaft-log may next be cut to dimensions and fitted to place. The deadwood is a body of timber built up on top of the keel to afford a firm fastening for the planks rising obliquely from the keel. The shaft-log must be of clear, straight-grained oak, having a longitudinal hole cut through its center of a size suitable to accommodate the shaft tube. It is usually formed by a couple of timbers bolted together with galvanized iron bolts.
In assembling all these members of the structure care should be taken to see that the joints between timbers are perfectly tight. They should be treated with white lead and closed with “through and through” fastenings.

Erecting the Molds.

The next step is to erect the section molds, made in the manner already described. After placing them at the proper stations, which should be marked at regular in- tervals on the keel, they must be centered and squared up with the keel and then fastened in place securely by means of braces and ties.
Each mold should be carefully plumbed fore and aft and sideways before being braced in place. A straight edged board several inches wide should then be nailed on the center line of the cross-pawls, one edge being just at the center line. By means of this straight edge, each mold can be squared athwartship and should be nailed at the top to a batten extending longitudinally around the molds from stem to stern. To insure the molds being plumb sideways, a spirit level may be set on top of each cross-pawl to see that it is level from side to side. Then the mold can be braced securely from above on each side.

The molds having been secured in place, we may now proceed to put in the ribbands.
These are strips of wood bent over the molds and fastened to them from stem to stern along the lines of the planking. They help to retain the molds in place, and when fitted will also serve to show any defects in the lines of the hull. The molds should be of sufficient height to allow the upper ribband to be fixed above the point designed for the sheer strake and thus serve to support the frame until the sheer strake and clamp piece are in place.

The ribbands may also be made large enough and numerous enough to enable the frames to be bent in against them to the proper form. This, however, is only done in the case of small boats.

Bending in the Frames.

Bending in the frames will be the next operation. The material for these should be carefully selected and extra pieces should be provided, as some are likely to break in bending. A good material is tough clear white oak. In order to make the frame timbers bend evenly, they should be made of uniform thickness by being run through a planer after being sawed out. As already stated, small frames may be bent directly to the required form against the ribbands, but usually the frame after being properly sized, must be first steamed. It is then taken immediately to its place, bent in to the required form, then secured to the keel, clamped to the ribbands and carefully adjusted in the proper position.

For the purpose of steaming frame timbers, a is required. This may be about 14 inches square and 12 feet long. It can be made from common pine boards, well cleated on the outside and one end closed tight. “The other end is left open to receive the frames, but when in use is closed by a temporary door or even by a bundle of rags stuffed in tight. In, order that the frames may be set in the hottest steam, slats should be fixed across the inside of the box and the frames placed on them. An ordinary wash boiler with a tight wooden cover will give plenty of steam and it can be taken to the box through an iron pipe or rubber tube. Frames should be steamed about an hour and the steam should not be allowed to go down, but should be kept hot until the frames come out. See in following chapter.

For larger boats, when the frames can not easily be bent in against the ribbands, they are usually formed on a bending floor or by means of frame molds. When they are formed on the floor the exact shape of the frame on the inner or concave side is laid down on the floor. Pegs or nails are driven into the floor along the line of the design and the steamed frame is then bent to the required shape against these pegs or nails. Sometimes special molds are cut for each frame and with this as a foundation the frame is bent to form.

Whenever the shape of the frame will permit, it should run in one continuous piece from rail to rail without any joint at the keel, but this can apply only to the frames in the midship section of the boat. Nearer the stem and stern, where the angles at the keel are sharp, the frame is necessarily bent in in two parts, these being secured to- gether by a chock at the bottom. When bent to form, either as one continuous piece or in two parts, however, the two sides of the frame are firmly secured by cross ties, so that when erected in the hull, it will retain its form.
When in place at the proper station on the keel, each frame should be permanently fastened thereto, with a temporary fastening to the ribbands by clamps. The heel of the frame may be fastened to the keel by two galvanized wire nails, which should be bored for and have their heads countersunk. The fastenings to the keel will include the fitting of chocks and bent floors with keelson, the latter being a continuous strip running fore and aft, securely fastening the flooring to the keel. The floors, which may be of one-inch timber, are usually fitted to the shape of the frames and notched closely over the keel. They must extend high enough to reach to the bottom of the cabin or cockpit floor, which is fastened to them, and they may be bolted to the keel with ^ inch galvanized bolts and riveted to the frames with two rivets on each side.

Limbers must be cut in them and these should be of sufficient size to prevent them clogging up, small ones being of little use. For the benefit of the novice, it may be stated that these “limbers” are holes cut through the floor timbers to permit the draining of water to the bilge or pump well.

When the frames are well set, the molds can be taken out, care being taken before doing this work on the frames which are the height of cross-pawls, to put stay laths across at each mold, well fastened to the upper battens, and transfer the overhead braces to the stay laths.

Planking and Seating.

The skeleton of the hull being now set up, it is ready for the planking or outer skin. This should be prepared in lengths as long as possible, each plank being tapered toward the bow and stern, so that there may be the same number of strakes from stem to stern. The edges of the planking will then come as nearly as possible at right angles to the frames.

If the method of construction involves a double layer of planking, the outer layer should be so arranged that the joints will not correspond with those of the inner layer. After the inner layer is put on, its outer surface may be painted thickly with white lead, special care being taken to cover the end joints and seams. If the joints and seams of the second or outer layer of planking are also similarly painted or covered, it will help to make the skin perfectly water-tight.
Before fitting the longitudinal planks, the ribbands formerly noted must be removed with the exception of the topmost ribband, which, as we have stated, should be sufficiently high to clear the sheer strake and clamp piece. When the planking has progressed as far as the sheer strake, the latter is carefully fitted. This covers the topmost strake of planking and is securely fastened to the frames and the construction strengthened by means of the clamp piece or longitudinal member on the inner side of the frames, the whole being firmly bolted together.

The upper ribband may now be removed, after a few ties have been run across from one side of the hull to the other. The tops of the frames are then cut off and the molds, if still standing, are removed.
The rail is then finished and may be made with a cap piece to cover the sheer strake, clamp and space between them formed by the frame ends; or the space between the frames may be filled in flush with the sheer strake and clamp pieces; or the combination of sheer strake, clamp and frame ends, may be left to form the rail.
In most cases, bilge and side stringers should be put on to add to the longitudinal strength of the hull.

With regard to the foundation for the engine, complete instructions will be found in the section devoted to installation of engines. Details of this work depend altogether upon the size, weight and design of the engine.
As already stated, however, care should be taken to put in a foundation of sufficient size and length to distribute the stresses caused by the operation of the engine as far as possible throughout the hull.

Seating In order to support the seats called for by the boat design, whether these are fore or aft or across the boat, suitable stringer pieces are fitted on the inside of the frames and securely fastened to them. The seats being carefully fitted and fastened to these stringers, will add to the strength of the structure, acting as braces for the side, especially in the case of transverse seats, which, when properly fitted, add greatly to the lateral strength of the hull, preventing compression of the sides or bulging as the case may be.
Fore and aft seats, when properly fitted, add to the longitudinal strength of the sides, as well as increasing the transverse strength. When fore and aft seats are fitted, their inner edge is supported on posts standing on and fastened to a stringer piece secured to the frames.
Chocks or brackets may also x be fitted under the seats to add to the strength of the construction.

If the boat is to be decked or partially decked, the next step is to put in the deck beams and then the deck planking over the space to be covered.
If gasolene tanks or air tanks are to be installed beneath decks, these must, of course, be set in place before the space is finally closed.

Finishing the Exterior.

When the work of construction has reached this stage, the exterior of the hull is ready for planing and finishing. The first step is to rough plane the planking and then to calk and fill the joints carefully with thick white lead or other suitable material; then the entire exterior can be finally planed, smoothed up and prepared for painting and puttying.
In the case of single planked boats with a thin skjn, great care must be taken in the final planing not to weaken the structure by removing too much of the surface of wood, as the thickness of the timber will not stand it. Judgment must be used in such cases, in order to secure the best results in the form of the finished exterior without sacrificing the strength of the structure.
It will readily be seen at this point that special care must be taken in all the earlier stages of the work, so as to secure the precise form designed. Hence, at every stage, especially in preparing the molds and frames, dimensions must be carefully observed and workmanship must be exact, in order to secure the form required. After the frames are in and the planking fitted, it is too late to correct any error in the external lines of the boat and this fact should be borne in mind from the moment of laying down the keel.

If the boat has been built on approved lines with careful attention to details of workmanship and design, the exterior of the hull will emerge from the operations of planing, scraping and sand papering in a form to delight the eye of the builder.
When double planking is fitted, the operation of calking is not always necessary, but in the case of thick planking it is usually best to calk. The operation of calking is the driving of cotton or oakum into the seams with a calking iron, or broad form of chisel and a mallet, in order to prevent the penetration of water. The oakum or cotton is forced below the surface by means of the iron. In the construction of large boats and in shipbuilding, the seams are usually covered with melted pitch.

With thin planking, less than half an inch thick for instance, the seams would hardly retain the cotton, hence, when the thinner forms of planking are used, it is necessary to use it in two layers with shifted seams, this construction obviating the necessity of calking. White lead is freely used to protect the seams.

Painting

Care should be taken to use only the best kinds of marine paint. Three or four coats can be given, each coat being rubbed down before the next is applied, and plenty of time being allowed for drying between coats. If this is properly done, the result will be a smooth, hard surface of lasting quality.
A typical course pursued by boat-builders in finishing is as follows: The entire boat is sanded to a smooth surface and given a coat of hot linseed oil. Over this are applied three coats of copper paint below water line. With three coats of pure white enamel marine paint above to sheer strake, the entire interior, with frames, is treated to one coat of linseed oil, put on hot, and two coats of pure red lead paint. Sheer strake, fenders, covering boards, decks, coaming and interior of entire cockpit are finished natural in three coats of best spar varnish above filler.

In the above we have referred particularly to the construction of small boats and launches made over molds with the old form of stern and deadwood.
In the construction of larger boats of the same general design, the frames are heavier and stiffer in proportion and being molded or bent to form on the floor after steaming, the use of molds is unnecessary.

The keel, stem and stern posts are set up in the manner described above and the frames being then erected in place and ribbands fastened along the sides, the boat is “in frame” and the further steps of construction, including planking, decking, seating and finish, are conducted in the same general way as in building smaller boats.
When a more modern form of stern is adopted in the design, such as the well-known torpedo stern, the various steps of construction are practically the same as in the older model, but the keel is usually a flat timber, rather than square as in the old style boat. Provision also has to be made to support the shaft tube and shaft properly where these pass through the bottom of the boat. Supports must be provided, not only for the shaft bearing at the point of passage through the bottom, but also at the point where the shaft emerges into the water, just forward of the propelle’r. This may be in the form of a steel or bronze bracket securely fastened to the stern to support the shaft bearing.

It being impossible within the scope of a work of this size to describe in detail all the varied processes required in the building of the innumerable models now seen in American waters, we have endeavored to give a general practical idea of the methods of procedure commonly employed in building boats and launches of types generally regarded as normal, and designed for moderate speed and cruising purposes. At the same time we have shown the peculiar forms of construction used in building speed craft, such as the special methods of framing, the use of extra thin planking, sometimes with varnished silk or other fabric between layers, and other features tending to secure the rigidity of structure required where lightweight, high-speed engines are installed.
Our description of the methods commonly employed will suffice to start any amateur who possesses a slight knowledge of carpentry on the right road to success in building his own boat.
Equipped with the knowledge furnished in the preceding chapters, he will be stimulated to an intelligent study of the plans from which his boat is to be constructed and will know how to set about the routine of operations required in all boat construction.

Specific instructions for the building of a typical power boat from patterns will be found in detail in the next chapter, and these will furnish any points that may not be included in the general outline of operations already given.

Choice of a boat model

13 Oct 2011 at 22:20

captain

How to build a boat

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In making a choice of a boat model, whether for the purpose of amateur boat-building or in buying a completed ‘hull, there are several main considerations to be taken into account. First of these is the question of sea-worthiness. If the boat is to be used on the seacoast or the , the possible range of travel and the depth of the waters to be navigated demand a greater beam and greater stability in other respects than are required in craft intended for the navigation of narrow and shallower waters.

The problem of the form and structure of the boat involves the selection of a craft having the proper carrying capacity, stability and comfort, designed along lines that will present the least resistance at a required speed.

If the inquirer intends to build his own boat or to install his own engine in the hull he selects, the weight of the engine to be installed is an important factor. He will do well to obtain the views of an experienced boat-builder or of a marine engineer, capable of making the necessary calculations of the displacement of a boat.

If his object is to secure a boat to run at high speed, he will need a model in which the lightest possible construction is combined with the strength required to support the engine and resist the stresses set up by its vibration.

If he desires only a moderate speed boat, he may select a model of safer and stronger construction, of greater beam and higher freeboard, having the advantages of more room and carrying capacity; in other words, a craft of a more seaworthy and general safer character.

The infinite variety of boat models now offered to the public in all stages of construction, including patterns, knock-down frames and completed hulls, offers a wide range of choice. Many of these models of approved construction, popular among boatmen East and West, are illustrated in these pages. On every body of water other models can usually be seen and as a rule the person who starts out to purchase a boat or to construct a hull for him has a fair general idea of the kind of craft he requires.

A number of the boats have come, by reason of long and successful operation, to be regarded almost as standard models and the novice in will not go far wrong if he selects one of these boats of generally approved design.

As stated elsewhere, the novice should be careful to avoid “freaks,” that is models in which some peculiar individual idea or ideas have been embodied at the expense of recognized lines of construction. Freaks are apt to prove expensive, even as experiments, and the wise boatman usually sticks to approved designs, leaving it to skilled naval architects to originate new ideas in design and have them thoroughly tested before recommending them for general adoption.

The matter of the proportion of the length of the boat to its beam is one upon which no definite rule can be laid down. The higher the speed required, the narrower the proportional beam as a rule. The limit in present practice is the ration of 9 or 10 to 1 for high speed boats and the ratio ranges down to 4, or 5 to 1, which is the proportion of the length to beam in small and low speed boats. Moderate sized craft designed for fair speed, sea-worthiness and comfort may show a ratio of 5, 6, or 7 to 1 between length and beam.

Careful sailors agree that, speaking generally, a launch should have a beam about one-fifth of her length on the water line, when it is intended for seagoing or to withstand heavy weather. In small boats the beam should be about one-fourth of the length on the water line. This applies only to boats of moderate to fair speed.
The draft of a boat is determined by the form of the hull and weight of the loaded structure. Increase of the beam results in lessening the draft, and vice versa.

General Form of the Hull.

As regards the general form of the hull, there are certain principles that may be mentioned here; as, for instance, the flare at the bow and sides from the water line to the sheer. The greater the flare outward, as a rule, the less water the boat will ship in a seaway, but flare retards speed, while adding to comfort and safety. This is seen in the seagoing dory with its splendid stability in all weathers.

For seagoing craft a wedge-shaped bottom is preferable and in heavy weather adds greatly to the comfort of the occupants.

A certain amount of sheer or rise at bow and stern is another desideratum in seagoing craft and this applies to boats intended for use on the Great Lakes, where heavy weather is apt to be encountered and conditions often strongly resemble those encountered on the seacoast.

The sheer is always greater at the bow than at the stern and adds to the lifting power of the hull in a seaway.

A certain amount of decking should be fitted in all open launches at the bow and stern. The forward deck helps to keep the boat dry and the decking aft protects the occupants in heavy weather from “following” waves climbing over the stern. Such decks do not decrease the capacity of the boat since the space beneath can be used for stowage, and they add greatly to comfort and safety, by keeping the machinery, accessories, clothing, etc., dry. A certain width of deck should be fitted the whole length of the boat on either side or these side decks should not be made too narrow.
The height of the coaming or washboard around the cockpit is a matter of choice and is governed by consider- ations of appearance and convenience. A high coaming helps to keep out spray.

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Cruisers are distinguished mostly by the character of the cabin fittings. Some have a short cabin with a large cockpit, while in others most of the interior space is occupied by the cabin, with a small cockpit aft.
Cabins are often of what is called the trunk type, a gangway to the bow being left on either side of the trunk. Another type of cruiser has a flush deck forming the cabin top, in which case the sides of the boat are brought up flush and the deck may be slightly rounded to form a “turtle back.” This style of cabin affords more room inside and by many is regarded as less liable to leakage in a heavy sea.

Naval architects have rung the changes on these two leading types of cruisers, so that a wide range of choice is offered to the amateur builder or purchaser, and cabin cruisers nowadays may be a delight to the eye by their handsome appearance while at the same time affording a maximum of accommodation for comfortable cruising.

The past few years have seen a wonderful advancement in the construction of cruiser craft. In the past decade the gasolene engine and the motor-boat have revolutionized the field of sport and recreation, but only of very recent years have people come to realize the real utility and practicability of the cabin cruiser, and that such boats are capable of cruising safely in any waters of the globe. The four boats which in 1909 entered the New York to contest ranged only from 42 to 85 feet in length and raced across the open Atlantic 800 miles.

The past few years have seen a wonderful advancement in the construction of cruiser craft. In the past decade the gasolene engine and the motor-boat have revolutionized the field of sport and recreation, but only of very recent years have people come to realize the real utility and practicability of the cabin cruiser, and that such boats are capable of cruising safely in any waters of the globe. The four boats which in 1909 entered the New York to Bermuda contest ranged only from 42 to 85 feet in length and raced across the open Atlantic 800 miles.

To anyone living upon the coast, the Great Lakes, the Mississippi system, or any of the rivers tributary thereto, the cabin cruiser affords the greatest opportunities for healthful and delightful recreation. It is as cool, convenient, and comfortable as a summer cottage, never grows monotonous, because of continual change of scene, and can be operated at very small expense. Realizing the advantages of this type of boat, and that its popularity must increase with each succeeding season, the leading boat-builders have, during the past few years, exerted every possible effort to perfect the design of their models and to improve the interior plans in order to secure the greatest serviceability and comfort, and the most pleasing general appearance at the least possible cost.

“The greatest need in the motor and boat business,” says an acknowledged authority”, is more information on marine engines.” We shall, therefore, first describe and illustrate the principles, construction and operation of the various marine gasolene engines in present day use and then proceed to the subject of practical boat-building.

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Typical construction on the Great Lakes is exemplified in the motor-boats built by the DeFoe Boat and Motor Works, of Bay City, Michigan. As there are special features found in the DeFoe boats not found in any other, we give the following detailed description of their construction:
The entire frame is of perfect, straight-grained white oak. Ribs are steam bent and closely spaced, from 4 to 8 inches apart, depending on the size of boat and thick- ness of planking. The sheerstrake is of either oak or mahoganized birch to correspond with the decks and coaming, and balance of planking of clear Louisiana red cypress, with all fastenings either screwed, bolted or clinch nailed, making the strongest possible construction.
All joints are reinforced between frames with oak butt blocks. The plank seams are caulked with cotton, payed with white lead and puttied flush, nail heads countersunk and puttied and screw and bolt heads plugged, leaving a perfectly smooth surface.

Inside, beneath the covering boards, heavy oak clamps are bolted to the sheerstrake and ribs, adding strength and firmness to the whole frame. Deck beams and breast hooks are sawed to shape and firmly fastened in position. Covering boards cut to shape. Decking laid in narrow stuff, caulked, payed and puttied flush the only way to make a perfect deck.

“Bulkheads at each end of the cockpit are paneled with doors, giving easy access under the decks. The gasolene tank is so arranged that it can be easily removed at any time, and is of extra heavy galvanized iron with swash plates fore and aft and athwartship to prevent undue strain by the shifting of the gasolene in a seaway. The floor is covered with linoleum and entire cockpit is artistically paneled throughout.
“Rudder is of steel plate. Steering boards clear, but with all parts of the easily accessible at any time for repairs. Steering wheel of polished brass with mahogany grips and drum. Cleats, chocks and all other deck and interior hardware of polished brass.”

A fine example of a steel motor-boat in popular demand is the 1910 Special 18-foot model built by the Michigan Steel Boat Company, of which two photographic illustrations are shown. This boat has a beam of 4 feet 6 inches and the cockpit is 11 feet 4 inches long. The depth is 2 feet amidships, 2 feet 7 inches forward, and 1 foot 10 inches aft. Equipped with a 3,2 H. P. Detroit engine, the boat makes a speed of 10 miles an hour. It seats ten persons in all, the forward cockpit seating six, having seats 4 feet 6 inches long and 10 inches wide. The net weight of the boat is 650 pounds; crated for domestic shipment, 850 pounds. The measurements boxed are 18 feet 3 inches by 4 feet 8 inches by 3 feet 4 inches, or 284 cubic feet. The price of this model complete with engine installed ($147, crated, f. o. b. cars at Detroit) brings it within the reach of the most moderate incomes. In materials, workmanship and power, this 1910 boat is fully up to the well-known standard of the Michigan Steel Boat Company in every respect.
The launch can be equipped with an engine as large as 12-14 H. P. if desired. With such an engine installed it has made actual speed over a measured course of 19 miles an hour. Of course the price with the larger engine is comparatively higher.

“Matthews” Craft.

Among the boat-builders who have aided greatly in the recent development of motor-boating by the production of excellent and popular models is The Matthews Boat Company, of Port Clinton, Ohio. The methods of construction adopted by this concern possess many features of general interest.

For example, as shown in the illustration, the method of construction followed by some builders-includes a small single keel; two-piece frames on top of keel, cut at the weakest point; large bevel seams in planking, stuffed with calking; open seam at garboard, to cause “garboard leak-age,” and garboard plank fastened to frames only. The Matthews method includes stronger “backbone” construction; garboard plank lapped under keel, to obviate open seam and give longitudinal fastenings; single-piece frames, rabbeted or slotted under inner keel to increase strength w r here most needed, and small, tight seams of planking, with small strand of calking.

The Matthews open launches have been built in large numbers and have attained popularity as moderate-priced outfits. Their cabin cruisers are also well-known craft.
These boats are mentioned only as illustrations of the wide range of choice offered nowadays to the man who would a-boating go. No matter whether his main desideratum is speed, safety or luxury or a combination of all these points the boat builders stand ready to supply his needs at short notice.

Building a Boat from Patterns

13 Oct 2011 at 22:18

captain

How to build a boat

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Complete instructions for building from paper pat- terns a motor boat or launch from 16 to 30 feet or more in length are given in the following pages. A typical boat for a novice to build would be, say, an 18-footer of standard stern, about 4 feet 2 inches beam, designed to carry six or eight persons and to run 8/2 or 9 miles an hour when equipped with a 3 H. P. motor.
The necessary patterns (or knock-down frames, if desired) for building such a boat or indeed a launch of any size or style can be obtained from the boat-builders who make a specialty of such business. The instructions and forms of design given in the various sections of this chapter apply particularly to the patterns furnished by the DeFoe Boat & Motor Works, of Bay City, Michigan, where the pattern system originated.

Section 1. How to .

If the sheets are large and unwieldy cut them up into convenient sizes, taking care not to cut the lines of any pattern. Lay the pattern you wish to use on your material, hold it carefully in place with weights or tacks, and trace the lines with a tracing wheel, bearing on sufficiently to leave the imprint on the wood. Remove the pattern and cut out the piece. Be careful to leave enough wood outside the pattern lines so that the piece will smooth up to the exact size of the pattern.
Another method is as follows: Prick holes through on the lines of the pattern with an awl. Make them about 18 inches apart on lines slightly curved and from that to very close together on lines greatly curved. Remove the pattern, stick nails into the awl holes, bend a thin batten along the nails and mark the line by it.
Be careful to use your material to the best advantage, and cut the parts out in a way to leave the least waste. You can make a big difference in the cost of your boat in this way.
In placing your pattern on the wood be careful that the grain runs in the proper direction to give the greatest strength. For example, the grain in the breast-hook (Fig. 6) should run crosswise, in the transom-knees diagonally, etc.
Do not cut your paper patterns out to exact size, as a long narrow pattern, such as a plank pattern for example, would be apt to lose its shape. It is a good plan, after each part is finished, to place it on the pattern again and see that no mistakes have been made. Do this every time without fail.

Section 2. Materials to Use.

All lumber should be well seasoned and air-dried rather than kiln-dried, as kiln-drying makes it brittle.
White oak is by far the best material to use for the frame-work of the boat. Rock elm may be used. Firmay be used for stem, keel, etc., but it will not bend for ribs.
For planking use white pine, cypress, or cedar if it can be obtained and it generally can. Southern pine may be used, but it splits easily and is difficult to work and to hold in place. Avoid basswood, poplar, etc., unless your boat is to be canvas covered, as they will not stand the water. Fir or spruce may be used.
Buy good lumber. Wide boards cut with less waste than narrow ones. Cross-grained, knotty or shaky stuff will split and you will waste more in working it up than you will save on the lower price.

Section 3. Keel, Stem, Stern-post and Skeg.

Keel The first part to construct is the keel. Using patterns as directed, cut the keel to shape, and if made of two pieces (as in the larger boats), fasten together with a butt splice. The keel is now finished.

Stern First saw out stem and stem-knee from the patterns, and bolt them together. Mark the rabbet line on both sides, and with a chisel cut the groove, called the rabbet. The ends of the plank are to be fitted into the rabbet, and hence it should be as deep as the plank is thick.

Cut the rabbet with plenty of bevel, so that the plank will slip in easy. The rabbet line and bearding line are shown on the stem pattern. In compromise stern boats the stern-post is put together and rabbeted exactly as the stem.

The skeg is made of stuff two to four inches thick, depending on size of boat. Have it thick enough that there is plenty of room for the shaft hole, though not so thick as to be cumbersome. If you haven’t the means of boring the shaft hole rip the skeg in two on the line of the shaft and gouge out the shaft hole. Then fasteri the two pieces together again by means of a flat cheek piece screwed firmly on each side. Fit this piece on carefully and bed it in white lead and you will never be troubled with leaks. The stern post is put in to make a better fastening for the shaft bearing, as the screws would not hold in the end of the timber of the skeg. The figure shows how to fasten stern post to skeg and put in stopwaters. Paint the skeg and keel where they are to be joined and. lay a thin sheet of rubber or canvas between them to prevent leaks, and fasten skeg to keel by nailing down through keel. Nail thoroughly, boring a small hole for the nails to prevent splitting.
A stopwater is a small pine plug driven into a hole bored for it, to prevent a leak in a spot that cannot be reached to calk. Fit them carefully and they will swell enough to prevent the leak. A little study of the illustration will show you just why they are put in certain places.

Section 4. Setting Up Frame.

Molds

The next step is to make the molds. They may be made out of any rough cheap stuff, as they are not a part of the boat, but simply forms to build it over. Wide boards will work up handier. The pattern of but half the mold is given. Cut out one half of the mold and use it to mark the other half by. Get the distance across the top from the pattern, and also mark the center of each mold.
Next, from a two-inch plank 8 to 12 inches wide, construct a long horse for the purpose. Malte it straight on top, and nail the legs to the floor so as to brace it straight in line. Compromise and torpedo stern boats draw more water forward than aft and it is better to raise the horse on longer legs at the stern end so that the boat will set while building about as it is supposed to set in the water. The builder can then better judge of his work while he is building.
Bolt the stem and stern-post and skeg to the keel, place the whole on the horse and fasten keel down to the horse so that it will be in line, that is with no kinks or bends in it.
Fasten the molds to the keel (keel pattern shows where they belong) by nailing a block on the keel and the molds to this block. Fasten them square across the keel and perpendicular to it. Nail a board with a straight edge (splice two together if need be) from stem to stern on top of the molds, bringing the center line of the mold to this straight edge, Fig. 1. This is to hold the mold square across the keel and perpendicular to it.
Plumb up the stem and stern with a plumb bob, and brace the whole thing either to the roof.

Thesheer strake is the top plank of the boat and the sheer line is the top line of this plank. The top of each mold will just come to the sheer line if you make them exact size of pattern and the point where the rabbet line ends on the stems is the sheer line.
Next put on the ribbands. These are narrow strips of straight grained stuff free from knots. Put at least five ribbands on each side, screw them to the stem and stern and nail them with light nails to the molds. Neither molds nor ribbands are a part of the boat, but are simply used for putting in the ribs.

Section 5. Bending and Putting in the Ribs.

Everything is now ready for the ribs. These are to be steamed and bent over a form, or forms, and allowed to cool before using. It is generally best to use two or three different bending forms, as the ribs do not all have the same bend in them. Make these forms out of a piece of “fa” board, and use the molds for patterns. It is not necessary to make a form from every mold, but select the mold with the greatest bend and one or two others. Make the form so that the rib will have a little more bend than the mold, as it will spring back a little after it is bent. And it is a simple matter to straighten it farther if it does not spring back enough. Nail these forms down to the bench.
Procure a piece of thin band iron about the width of the rib and bend a hook in one end that will just fit over the end of the rib. Steam the ribs thoroughly for an hour. Clamp the iron strap quickly on a hot rib and immediately bent it around the bending form. Tack a stay lath across to keep it from straightening out and the iron strap may then be removed, the rib taken off the form, and the operation repeated on the next rib. Leave the ribs about an hour until they are thoroughly cooled.

Then the stay-lath may be knocked off and the rib is ready for use. Be careful that each rib touches every ribband or the outside of your boat will not be smooth. Fit the lower end to the keel, nail it fast, boring for the nail through the rib to prevent splitting it, and tack them temporarily to the ribbands. Cut ribs 5 or 6 inches longer than required length to be sure of a fit. Be sure to get the bend in the proper place, so that one end of the rib will not be too short. The ribs near the stems must be notched into thesides of the stem knee.
Floor Timbers Figures 1 and 6 show floor timbers. They are used to fasten the ribs together and to fasten them more firmly to the keel. Use oak about the thickness of the ribs and about l/2 to 3 inches deep. Lay the piece alongside the ribs and’ mark it. Then take it out and cut it to shape. In this way a good fit can be very easily obtained. Nail it firmly to ribs and to keel. Be sure to cut a limber hole in each one to let water run back to pump. Put a floor timber on every other rib. It is scarcely necessary to put them on every rib. The molds may be in the way of some of the ribs. If so, put these ribs in after the molds are taken out.
Be very careful to do all this work exactly to the patterns, for if your molds are not made correct in size and placed correctly, and if the ribs are not fitted exactly to the ribbands, of course the plank patterns will not fit.

Section 6. Planking.

The plank patterns are marked and numbered as follows: They are numbered 1, 2, 3, 4, etc., up from the keel, No. 1 being the plank next to the keel. This plank is called the garboard. No. 2 is the next plank above and so on. In large boats each plank will probably be in two or three pieces. The end of the piece that goes toward the bow is marked with an X and the pieces of a plank are lettered from the bow. For example consider the 12th plank on a 30-foot boat. You will find that it is in three pieces. One piece is numbered X, 12, A, the X meaning that this end points toward the stem, the 12 that it is the 12th plank from the keel, a.nd the A that it is the first piece of the plank toward the bow. The next piece is marked X, 12, B, the X and 12 indicating same as before, and the B that this is the 2nd piece of the plank from the bow. In shorter boats this plank would be in but two pieces. The proper edge of the plank is up when the number and letters on the patterns are right side up as the boat sets on her keel. Be sure to get the proper edge up. Mark the upper edge as you take the pattern off the board. The first strake of plank to be put on is the sheerstrake. Place the top edge even with the top of the molds and where the rabbet line ends on stem and sternpost (or top of transom in square stern boats). Most builders prefer to finish this in natural wood. In such a case all screws and bolts should be plugged. (See section on Painting, Varnishing and Finishing.) Screw the top edge to the ribs. The bottom is not necessarily fastened until clamp is put in (see section 7). In putting on any strake fit up and nail to the stem and stern first, then splice.
As each piece of plank is got out and fitted, use it as a pattern to cut a like piece for the other side of the boat. Be very careful to finish up both pieces the same size, so that both sides of boat will be exactly alike.
The plank patterns are all made about 6 inches longer than the finished plank is to be, to allow for sawing for the splice. Xail both pieces to the ribs except for the two or three ribs near the splice, and, holding the saw square across, saw both pieces off at once. This, of course, leaves the two pieces fitting perfectly, the saw cut leaving a space of about 1-16 inch between them to allow for calking. Make butt blocks of oak, as it will hold the nails well, and make them about the thickness of the ribs. Nail plank to both butt blocks and ribs from the outside with clout nails that will reach through and clinch. If sheerstrake is to be varnished, screw to butt blocks and plug screw. When the sheerstrake is on, put on the rest of the plank down to the bilge (i. e., where the bend comes in the ribs). Then the most convenient method is to turn the boat Qver, horse and all, (leaving the horse on will keep the. keel in line) plumb up the stem and stern, and put on the plank next to the keel, called the garboard. This is the most difficult plank to put on and takes some careful fitting. Then plank from both ways, leaving about the 3rd plank from the keel to go on last. This plank is called the shutter. Unless your work has been very accurately done the pattern for this piece will not be apt to fit. It is safest anyway to cut it larger than the pattern and then dress it down to fit. The only object in turning the boat over is to make it handier to work at. If you prefer you may plank it entirely right side up.
Two methods of holding plank to place and closing the seams tight while nailing. The chain clamp may be purchased of the pattern makers. The other method, though serviceable, is not as convenient. It often requires quite a pressure to make these seams tight. They should come up tight on the inside, but the edges should be beveled before putting on, so that the seam will be open about l-16th of an inch on the outside to allow the calking to be driven in. (See section on Calking.) After the plank is sawn out dress up the edges with a plane, and hold it up in place to see that it fits. At the same time bevel the edges a little to allow for the calking seam.
The planks that go on the bilge must be hollowed out a little on the inside to fit the curve of the ribs. This is easiest done with a round bottom plane. If you haven’t a round bottom plane, gouge out with your chisel where the rib goes, till you get a fit.
With few exceptions all planks will go on without steaming.

Section 7. Clamps and Breast-hooks.

When planks are all on remove the horse from the keel, right the boat up, and take out the forms. Place the boat at any convenient height for work, plumb up the stem and stern, and brace in position.
The clamps are located just the width of the deck beams below the top of the sheerstrake. They are straight pieces (preferably oak) and are sprung into place. They should be about l / 2 the width of the sheerstrake, and from 0.5 inch thick in 16-foot boats to about 1 .5 inches in 30-foot and 35-foot boats. They are bolted through every rib, the same bolt fastening lower edge of sheerstrake.
The breast-hooks are of oak, with the grain running crosswise, and rest on top of the clamps. Bolt and screw them in as shown in illustration. Make them thick enough that they will dress down even with the sheerstrake so that the deck will lie flat on top of them. Place breast-hook in stern also of compromise launches.
Have your floor timbers level so that keelson will lie flat on top of them. A % piece about the width of keel should be used. Fasten securely at stem-knee and stern, and to every floor timber, as this is the main strength of the boat. A keel and keelson construction such as this is immeasurably stronger than a solid keel piece such as some builders use, and absolutely prevents vibration.

Decks

But one deck-beam pattern is given, as this is sufficient. Cut deck beams to required length and get the shape from this pattern, since the curve will of course be the same in each beam. Deck beams are nailed on top of clamps and along side of a rib where a secure fastening may be made. Before nailing them in be sure the boat is spread out to proper width, according to forward mold which you have removed. Nail deck knees in a little high and then shape down even with deck beams so that decks and covering board lie level. It is best for the amateur to cut a true circle for the coaming, as the coaming will then go in much easier. A few trials with a pencil and string, will get the proper center. Strike the circle to come exactly tang-ent to the covering board, for if there is a short jog here the coaming cannot be brought up to fit.

Place the deck beams from about 6 inches apart in smaller boats to about 10 inches in larger ones. The distance apart of deck beams may depend also on thickness of decking used. Decking should be from 12 to 34 inch.
Put on partner piece first, then covering boards. Put little blocks of proper height on the clamp along the sides to hold the covering board.

If you wish you may make the partner piece from 3-16 to ]/4 of an inch thicker than the rest of the deck, letting it project above the rest of the deck this much. Cut the covering boards to shape. Xail the short pieces marked between the deck beams, and flush with them to hold the ends of the decking. Begin to put the decking on at the partner piece, and fill out to the covering board. This deck should be calked. Hence, leave seams op k en about 1-16 inch at the top and close them tight at the bottom. Calk with a cotton cord. Be careful to get these seams all true and even. Set the nails. Plane the deck smooth and scrape it before putting on coaming. Careful work is necessary for a good job on this deck, but it can be done by anyone who will take plenty of time and care to it. The seams are then puttied over the calking, either with putty to match the rest of the finish in color, or of another color that will give a pleasing contrast.
Method of making a canvas-covered deck. This makes a very serviceable deck, and is easily put on. Matched pine flooring is good stuff for the decking, or waste material from the planking may be used. Xo partner piece or cut out covering boards are used. Xail stuff on and then cut out for coaming circle, and trim off edge flush with sheerstrake. Paste canvas down with a paste made of rye flour. (Stir up flour with cold water and cook till it thickens.) Draw it tight as possible and tack over the edges where fender strake and coaming will hide the tacks. Paint canvas with several coats of thin paint. Green is a good color.
Strike a semicircle on the floor somewhat smaller than the circle cut in the deck, to allow for the coaming springing out a little after taking it off the bending form. Cut out some wood brackets and nail them firmly to the floor on this semicircle. Bend the coaming around the brackets’ as shown. When cool remove it and screw it into place, and then dress it down to the proper height. Plug the screw heads for a good appearance. Use butt blocks 7 to 8 inches long to put pieces of coaming together, and put them on the outside.

Interior Arrangement and Finish.

There is ample choice of a number of seating arrangements. The builder may suit himself in this matter, though the style with seats running all around cockpit is recommended as the best for boats under 22 feet in length, while any of the styles are suitable for larger boats.
Put in the floor beams so that the floor will come about at the bend of the ribs. To get them all level put in a beam at each end first and be sure that they are at right angles with the perpendicular of the boat, so that the floor will be level as the boat sets in the water. Also place them at such heights that the floor will be level fore and aft. Then stretch two lines connecting the ends of these beams and fit in the remaining beams so that they just come up to these lines at each end. Then lay the floor on these beams and it will be level.
A good interior finish is made by ceiling the cockpit with narrow strips of ceiling about iy 2 to 2 inches in width. This is put in lengthwise, starting at the coaming, and is easily sprung into place. If you wish to make lockefs under the seats ceil up with the same stuff, running the strips up and down. This when filled and varnished makes a very nice-looking interior.
If you want an extra fine job, panel the interior in the manner shown in Figs. 9 and 10. Get your stuff out from l/4 inch to 8 inch thick. Put in the tuning pieces, reaching from the top of the rib to the floor, of oak or any timber that will hold a nail well. Use small brads and countersink them with a small nail set. Nail the panels on first and put the stiles on afterward. Put the lengthwise stiles on first and put in the up and down pieces afterward. This takes some careful fitting to make a good job,, but anyone can do it if he is willing to take the time, and will throw aside a piece if it does not fit and make a new one. Paint the backs of the panels before putting them on. Panels of this make are just as durable as the tongue-and-groove panel, and are lighter and much more easily made. Make the width of the panel from 2.5 to 3 times the width of the stile, and make the panel from 2 to 3 times as long as it is wide. In paneling the side of a cockpit, for example, where the panels must be wider at one end than at the other, make the stiles the same width on the whole job and vary the width of the panel only. In paneling a cockpit use from 2 to 3 panels up the sides and 1 or 2 deep around the lockers. The builder may have ideas of his own for an artistic arrangement of the panels, as there is no set rule to follow.

Calking.

Use a small calking iron and a mallet. Calk the butts first and where plank joins stems. Use calking cotton if the seams are uneven, that is, wider in some places than in others. Do not put it in in long straight strands, but drive it in in little tucks or loops first. Go over about a foot or two of the seam in this way first, and then go back over it and drive it in solid. Be sure to get enough cotton in the first time, as it is a poor plan to put more in the seam after it has been once gone over. It is apt to work out if you do. Fill the seam about half full.
If the seams are fairly even you can do a much easier and perhaps better job of calking with a soft cotton cord instead of the calking cotton. Do not tuck this in, but run it in straight, and drive it down tight with a calking iron. Use only a single strand. If you have carelessly left a seam too tight to get the calking in, open it up first by driving the calking iron along it.
When the calking is done paint the seam with thick paint, being careful to touch all the cotton. This will keep it from coming out.
Calk before the boat is painted. After first coat of paint, putty the seams and nail heads.
The cross pieces must fit down to the planking and be nailed fast. Nail from the outside of the boat. Bolt the cross piece through the keel. Put the ‘bolt head outside and sink it flush in the keel. Fit a block .between the keel and keelson where the bolt goes through so that the bolt will not bend them together. Fasten the motor to the lengthwise pieces with bolts or lag screws. Dotted line shows position of motor. Of course this bed must be just the proper height and pitch to bring your engine in line with the shaft. Stretch a line through the shaft hole to the point where the forward end of engine shaft will come, and make the top of the bed come level with this line. As DeFoe motors have the flange pieces for fastening to the bed on a line with center line of the shaft, the engine will then be in line when it is placed on the bed. As the line must be taken down before the engine is placed, mark the points, by nailing pieces up to the line from the keelson where each end of the engine shaft should come in order to be in exact line with the stern bearing. Of course the engine shaft should lie exactly where the line was. This will bring it if you are careful. Measure the engine shaft and get the two points just this distance apart. The lag screws that fasten the fore and aft pieces to the forward cross piece will in most cases fasten the engine down also. The dotted line shows the position of the engine on the bed.

.

Use a piece of gas pipe for the port, thread it on one end and screw it into the wood. Make the rudder of common sheet steel about inch thick, and make the rudder post and lower bearing of round iron about inch in diameter in smaller boats to 1-4 inches in larger ones. Square the upper end of rudder post to fit the tiller. Split the lower end to straddle the rudder, and rivet it on securely. Attach the lower bearing, Fig. 3 (a), in the same way, where a shoe is used, and make the shoe of iron. Turn the end of the shoe over as shown and put a key in the end of the bearing to keep rudder from jumping out.
The stuffing-box may be put either inside or outside better outside on small boats at least, as it needs no Moreover, if it is properly packed it will not need further lubrication there, and if it should need repacking it would be no great task to raise the boat up to reach it attention for a season at least.
Use cotton sash cord to connect tiller with steering wheel. The best arrangement is to keep the tiller below the deck, and run the cords around just below the coaming on each side to the steering wheel. Use blocks at the four corners where there is a quick turn, and small screw eyes under the coaming. Some prefer to have the tiller and ropes above the deck. In this case use four small cheek blocks and small brass eyelets to carry the cord. It will be necessary to bore holes in the coaming forward to get the ropes to the steering wheel if they are put above deck.

.

Use a common laundry room boiler, or a good sized kettle or pail will do for a small box: Make the box of 8 inch boards. Nail it solidly and make the joints very tight to hold the steam. Leave the ends open. A seven-foot box that will take a 12 inch board is large enough for most purposes. Cut a cover for the boiler from a 8 inch board and make it just large enough to slip into the boiler and fit snug. Nail the cover to the bottom of the box. Put two or three inches of water in the boiler and set the whole thing on the stove. If you have no stove handy set it over a fire built out of doors. Get it as hot as possible.
Put the material to be steamed in the box and plug up the ends tightly with rags. If you are steaming a long piece, such as a coaming, let the ends stick out of the box and pack around them with rags to keep the steam in. The amateur may work out a scheme of his own that will answer equally well; but this box, though crude in appearance, will answer all purposes.
By far the best way to treat the ribs for bending is to procure a metal trough that is long enough to hold them, and boil them in it for a half hour or so. Put a cover on the trough and boil them hard, and they can be made very pliable. The steam box will answer, however, unless ribs are of poor stuff.

Shop, Tools, Etc.

If you have a shop and a full set of tools, so much the better, though the ordinary tools to be found in most every household with very few additions will be sufficient. A hammer, handsaw, ripsaw, screwdriver, jackplane, smooth plane, a chisel or two, a brace and a few sizes of bits, about a half dozen clamps from 4 inches to , 8 inches and a draw-knife. If you haven’t all of them borrow them of your neighbor and give him a ride in the boat when it is finished. Keep your tools sharp.
A light, warm shop is of course the most desirable place in which to build your boat. But if you haven’t such, fit up the basement, the woodshed, or the barn. Put a bench along one side about 14 feet long. Use planks for the top, and it should be about the height of the builder’s hip joint. Have a vise at the left hand end. Of course the more convenient the shop, and the better the tools, the more pleasant will be the work, and naturally the better will be the results.

Painting, Varnishing and Finishing.

Use white lead and oil mixed very thin for a priming coat of paint. Next putty all nail heads and seams. A good boat putty is made by mixing whitening with white lead, (not the dry lead, but the ordinary kind which is ground in oil) until it is the proper consistency. Add about a teaspoon of Japan dryer to every pound of it before mixing. A quick drying and very durable putty is made by mixing equal parts by bulk of whitening and dry white lead with varnish. Any varnish will do; some old stuff, perhaps, that you may have around the house. This putty is sticky and hard to apply smooth, but will dry hard in three or four days. Sand the hull down perfectly after puttying, and apply at least two or more coats, sanding between coats. Be sure that each coat is thoroughly dry before you apply the succeeding one.
For a varnished finish proceed as follows: All screw heads, bolt heads, and the like, should be plugged with wood plugs. These plugs can be purchased at most hardware stores, or you can purchase a plug cutter, a cheap tool, and cut them yourself. They should be of the same wood as the remainder of your work and should be put in so that the grain runs in the same direction. Dip them in shellac and drive them into the hole and they will stay. When dry dress them off with a plane or a chisel. Then scrape and. sandpaper the wood to a perfect surface, as any little blemish will show up badly after the finish is on.
Next apply the filler. If you are building only one boat, it will be better to use prepared stains and fillers; and if you tell your dealer what results you want, light oak finish, dark oak, mahogany, cherry, or whatever it may be, he will furnish you with the proper materials. The boat and frame builders also carry these things in stock and will make immediate shipment if you order from them. Directions will usually be found on the package for applying the filler. A rub filler is recommended as giving the best results, and a water stain. There are many good fillers, but be careful if you use a stain, for they are apt to raise the grain of your wood or fade out in time unless they are exactly what they ought to be.
Sand the filler with fine sand paper, putty all nail heads, seams, etc., and when dry apply a coat of spar varnish, (get the best putty and use no other varnish than spar) and sand carefully, rubbing lengthwise of the grain only. Follow with a second coat in the same way, and finish with the third coat. Three coats of any good spar varnish are sufficient. Let the filler and .each coat of varnish dry thoroughly before the succeeding coat is put on. Otherwise it will check and may peel.
An excellent rub filler is made by mixing equal parts of whitening and cornstarch and adding turpentine until it becomes the consistency of paste. This will give a colorless filler and when applied will leave the wood its natural color and appearance. However, fillers are generally colored. In using a coloring matter, either dry or in oil, always dissolve it in turpentine before adding it to your filler or paint.
There are a variety of shades of finish for golden oak, mahogany, cherry, etc., and the best way to proceed is to purchase a few dry colors of brown, pink and red, and a little experimenting will produce a color that will suit your individual taste.
To apply the filler thin it with turpentine (use also about 4 teaspoonfuls of paint oil and a spoonful of Japan dryer to a quart of turpentine), and apply it with a brush, like paint, putting it on about as thick as paint. In from one to five minutes you will notice that dry spots will begin to show in the filler. Then take a handful of waste or an old cloth and rub off all the surplus filler, rubbing always across the grain of the wood in order to fill the pores. Finally use a clean cloth and rub off all the filler that will come off. The filler should then dry about 12 hours before the varnish is applied.
If you want a decided color, such as a very dark oak or a dark mahogany, use a stain first. You can make this yourself by simply mixing your dry powders with water and applying them to the wood with a cloth. Care must be taken not to leave the wood looking streaked. Apply the filler after the stain is on.

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Nail planking on with clout nails. Bore through or nearly through the part to be fastened, and have the nail long enough to reach away through and clinch over about 6 or 8. of an inch. Hold an iron against the spot and nail through against it to clinch or double the point of the nail over.
Always bore for a nail where there is any likelihood of splitting. Bore the hole about two-thirds the size of the nail.
Always bore for a screw full depth, with a bit slightly smaller than the screw, and countersink for the head of the screw.
White oak bends with steaming better than any other timber. For this reason it is often used for garboards (the plank next to keel) that are difficult to put on. For this reason also, and by reason of its toughness and durability, it is used almost entirely for frames. Dry timber bends better with steaming than wet timber.
Clamp the whole sheerstrake on before you fasten any part except to the stem and stern. You can better line it up in this way.
In using a bolt always put a washer under the nut.
Special Building Instructions for an 18-foot Standard Stern Launch.
In setting up the frame, keel sh’ould run straight from stem to fore end of skeg. Then raise the aft end of keel 3y 2 in. above this straight line. Do not let the keel curve down between the stem and skeg.

Carbureters

13 Oct 2011 at 22:17

captain

How to build a boat

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Gasolene vapor being explosive only when mixed with air in approximately such proportions that each molecule of vapor finds a certain quota of oxygen, a mechanical device to secure the proper mixture is an essential part of a gasolene engine. Mixtures, which are either too “rich” or too “lean” that is, those in which there is too great or too small a proportion of gasolene vapor are not explosive, and are ignited with difficulty, thereby interfering with the proper running of the engine.
The carbureter is the device usually employed to feed the gasolene to an air stream in suitable proportions to form an explosive mixture. In the commonest form of this device, a stream of air is drawn at high velocity past a nozzle, from which the gasolene is sucked and broken into spray, the gasolene entering the carbureter by gravity from the supply tank, a means of control being duly provided.
Numerous forms of carbureters are employed with gasolene engines, but the type almost universal on motor-boats is the spray carbureter. In this, the gasolene is drawn through a nozzle or jet by the engine, and as it leaves the jet in the form of spray, it mixes with air which is sucked into the engine at the same time.

The Float-Feed Principle.

Now, as the air must be charged with a certain proportion of gasolene vapor in order to obtain the best results, it will be apparent that the form and dimensions of the carbureter must be carefully designed, and that the flow of gasolene must be properly regulated. To accomplish the second object, a float valve is employed. Instead of being led directly to the nozzle the gasolene is fed through a pipe into a chamber in which is a float; nearly filling the same.
In some carbureters the floats are principally made of cork, but they are generally constructed of thin metal.

Pivoted to the top and bottom of the chamber of a typical carbureter are two weighted levers. The outer ends of these levers bear against the float; the inner ends engage in a grooved collar fixed to a wire or needle. This needle has a conical point adapted to fit into a corresponding conical seating at the point where the gasolene enters the chamber. As the gasolene gets deeper in the chamber it raises the float, the outer ends of the lever rise, the inner ends are forced down, and the pointed end of the needle is thrust farther and farther into the seating, so that when the gasolene has reached the desired height in the chamber the supply is cut off.
There is a small passage communicating between the float chamber and the nozzle, consequently the gasolene will stand at the same height in the nozzle as in the chamber. Usually the float valve device is arranged to keep the gasolene at about one-sixteenth inch below the level of the top of the jet.
More gasolene vapor being sucked into the engine when it is running at high speed, a proper air supply is important to maintain a mixture of the same proportions at high and low speeds. To meet this requirement numerous forms of automatic carbureters have been devised, most of which admit additional air at high speeds by a light valve opening against a spring. This is usually called an auxiliary air valve and the air thus automatically admitted at high speeds, reduces the richness of the mixture to the proper point.

Regulation of .

The flow of gasolene through the spray orifice is controlled either by an adjustable needle valve or by regulating the opening of the air intake. Reducing the size of this intake increases the suction and therefore the richness of the mixture, unless the auxiliary intake is separate, in which case reducing the primary intake weakens the mixture after the auxiliary valve is open. Changing either the needle valve or the primary air intake will increase or diminish the gasolene supply at all speeds, It is customary in adjusting a carbureter to begin by setting the needle valve or the primary air intake to give a good mixture when the engine is running on a low throttle with little or no opening of the auxiliary air valve. This insures easy starting and good control at low speeds. For medium and high speeds the auxiliary air valve is adjusted by regulating its spring tension and its maximum opening at high speed.

The Mixing Valve or Vaporizer.

If a marine engine is to be run at approximately one speed all the time, a simple mixing valve is often found to give good results. With this device, however, the mixture must be regulated by hand. This was the original method of mixing gasolene vapor and air in due proportions for combustion and the device is variously called a mixing valve, generator or vaporizer. It consists chiefly of an air chamber or passage in which a needle valve is situated. This valve is practically the same as the needle valve on the common gasolene stove in that- it sprays the gasolene into the burner. The burner in the stove would represent the mixing chamber. In connection with this passage or mixing chamber with its gasolene valve is a check or disk valve which operates in holding the vaporous gases in the motor as they pass from the mixer. At every up stroke of the engine piston, with the two-cycle motor, the partial vacuum or suction in the crank-case causes an influx of air through the mixing valve. The force of the incoming air lifts the check valve. This valve when it lifts, uncovers a small gasolene port, allowing it to spray the liquid into the air chamber, and become mixed with the inrushing air. When the engine piston starts downward, compressing the charge in the base, the check valve closes, holding the charge and also closing the gasolene port until the next similar operation.
This type of generator works very successfully but lacks the feature of a steady constant feed of gasolene where the gravity flow varies, as it does with a full or nearly empty gasolene tank. Again the varying speeds of the motor will affect the feed of gasolene into the mixing chamber. In both these cases it requires an adjustment of the needle valve, by the operator. This feature of constant care with the generator valve is often a worry to the operator under the conditions mentioned.
The improved float-feed type of carbureter is designed to obviate the difficulty of maintaining a constant flow of gasolene under all circumstances.

The “Puddle” Type.

In a new form of carburetors known as the puddle type, a float maintains the gasolene nozzle at such a level that it forms a small puddle in the bottom of a “shaped mix” tube. The inflow of gasolene to this puddle is controlled by a needle valve- and this adjustment, in connection with the depth of the puddle itself, determines the ipiality of the’ mixture. This carbureter does not act by spraying except at high speeds. At all lower speeds the gasolene is simply swept along the walls of the intake pipe and evaporated, The essential difference between the puddle and the spraying types is that in the former the gasolene feeds itself to the 1 air at low speeds, instead of requiring; a certain minimum decree of suction for that purpose. It will therefore make a mixture’ at lower speeds than the ordinary spraying carbureter. It has, however, certain peculiarities in operation, and very accurate adjustment of the float is necessary to prevent over richness of the “mixture”.

The Schebler float-feed carbureter in use on many motor-boats is known as Model and is illustrated herewith. It is manufactured by heeler Schebler, of Indianapolis, and is made in four pipe sizes, from one to two inches. It has been improved recently by the addition of a butterfly shutter placed in the air intake. This should be attached to a wire, running to some convenient place near the starting crank. When cranking, pull the shutter closed. This draws a rich mixture into the cylinders, causing the motor to start on the first or second turn of the crank.

Another improvement has been made on the air valve adjusting screw. A strong friction spring is placed around the adjusting screw between the lock nut and air valve casting, preventing the lock nut from jarring loose and thus allowing the air adjustment to change.

Cooling Systems

13 Oct 2011 at 22:17

captain

How to build a boat

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A high degree of heat being developed in the cylinder of a gasolene engine by the combustion of the fuel mixture lubrication is not sufficient to prevent the walls of the cylinder from becoming overheated. Unless this tendency is counteracted, the result will be the cutting and scoring of the piston and cylinder walls where they come into contact. Hence, it is absolutely necessary to remove excessive heat in the metal. There are two methods commonly used for this purpose, both being in successful operation at the present time. In the first and most common, water is used for cooling the cylinder, while in the second a current of air exerts the cooling influence.

The Water Cooling Method.

The water method consists essentially of a pump and a jacket around the cylinder, usually cast integral with it. This jacket forms a hollow pocket around the cylinder, through .which the water is forced and kept in constant circulation, thus carrying off the excess heat in the metal.

In the best modern practice the engine design is such as to allow for independent expansion between the cylinder and its jacket, so that the cylinder may expand and contract without reference to the jacket or barrel.

The pump to supply the cooling water, by means of a cold water intake and seacock, may be either a reciprocating plunger operated by an eccentric on the crank-shaft, or, in the case of a four-cycle engine, the valve camshaft. Rotary pumps are also sometimes used.

A certain amount of heat is required for the successful operation of an internal combustion engine and care must be taken by the engine designer that the cooling system does not remove too much heat from the cylinder. If the cylinder becomes overheated, there is danger of injury to both piston and cylinder, but on the other hand, if too much heat is removed, the efficiency of the engine will be lessened. The gasolene engine is essentially a heat engine and in the cooling system a happy medium is the object to be desired.

The Air Cooling Method.

The air method of cooling an internal combustion engine consists of a series of ribs or fins arranged around the cylinder, thus presenting a large radiating surface over which is usually blown a constant stream of air by employing a rotary fan similar in design to the ordinary electric fan. For marine work, where water is at hand, it is far more practical and convenient to employ it as a means of cooling the cylinder than air. The air-cooled cylinder is more liable to become overheated, unless some further means is employed to increase the circulation of air.

It was realized long ago by the foremost engine builders that the cooling problem of the gasolene engine must receive careful study or power and efficiency would be sacrificed, to say nothing of money for needless repairs. Hence the former idea that any sort of water cooling arrangement would suffice so long as it provided water in contact with the exterior walls of the cylinder, is fast passing away. In the best modern engines the proper degree of efficiency is secured in the water system in the simplest and most direct way, the cooling water pursuing in its course clean-cut straight lines, free from air pockets.

The coolest water in the cylinder jackets is near the bottom. The hottest part of the cool part of the jacket is where the exhaust comes from the engine. At that point the cold water supplied by the pump enters, in a typical modern system, and passing up and around between the walls of the cylinder and jacket, discharges at the extreme top of the cylinder. A generous sized concealed trunk main delivers the water to the cylinder, and a similar concealed duct receives the discharge from the cylinder jacket and carries it to the exhaust condenser, which leads the exhaust noiselessly to the side of the boat or through the bottom.

In frosty or freezing weather particular attention must be given to the draining of all water jackets and channels. This can be done, in the representative system referred to above, by simply removing the water drain plug at the end of the water channel under the crank-case and loosening the vent plug in top of the cylinder. If desirable for greater convenience, a pet cock may be inserted by the owner in place of the channel plug.

Pumps.

The pump is a very important part of the motor and should be specially designed to supply water to the cylinder jacket, in as steady proportion as the speed of the motor may require. It is sometimes a slighted feature of marine motors, its importance not being always properly recognized, but the tendency of modern construction is towards perfection of this feature of the engine, and very satisfactory pumps are furnished by some of the leading engine-builders.

The illustration shows the course of water circulation in the Ferro engine, which is equipped with a patent circulating pump. The latter consists of a small barrel with stuffing-box, in which a hollow piston works, driven by an eccentric, whose strap is pivoted to the piston by a pin. The eccentric is bolted to the crankshaft by a screw. The suction nipple is connected by a hose with seacock and intake passing through the bottom of boat, by which means the water is admitted to the valve chamber.
The stem of the suction valve slides in the discharge valve. Both valves drop into the valve chamber and make tight, easy fits on their respective seats. The bonnet which closes the valve chamber permits of instant inspection. The pump discharges into a concealed feed main, where it bolts by a flange to the engine frame, A try-cock drains the entire pump. If grit should cut the valve seats, it is a simple operation to grind them in by applying a little emery and oil on the valve seats and turning both valves in place by the wings on top of the discharge valve.

The action of the pump may be facilitated in drawing the water from the seacock or intake, by placing a scoop over the opening of the intake pipe. This scoop is a crown-shaped disk with two long openings on the side that catch the water when the boat is moving forward.

Don’ts For Motor Boatmen

13 Oct 2011 at 22:16

captain

How to build a boat

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Don’t fill gasolene tank by artificial light.
Don’t put gasolene in tank without straining.

Don’t try to run engine without gasolene in tank.

Don’t try to start the engine with gasolene valve closed.
Don’t try to start engine with worn out batteries.
Don’t try to run engine with soot fouled spark plugs.
Don’t go without tools in the boat.
Don’t cast off until engine is started.
Don’t start without lubricating oil.
Don’t neglect opening lubricators.
Don’t allow base of motor to get out of oil.

Don’t put too much oil in base.
Don’t fail to observe if water pump works.
Don’t neglect to oil clutch.
Don’t adjust clutch unless it needs it

Don’t let batteries get wet.
Don’t let wires run through bilge water.
Don’t let wire connections get loose.
Don’t stop motor until boat reaches mooring.
Don’t stop motor and leave charging switch in contact.
Don’t forget to close lubricator and gasolene valves when motor is stopped.

Don’t hesitate to write or ask for needed information.
Don’t use lighted match to examine contents of gasolene tank.

Don’t pack stern stuffing box with asbestos.
Don’t let bare wires come in contact with the motor.
Don’t let wire connections and terminals get loose.
Don’t blame the manufacturer or the motor for every little thing that happens.
Don’t forget that you are a factor in the successful running of the motor.
Don’t get nervous or excited sit down and think a minute.
Don’t forget that the builders are as much interested in the performance of the motor as you are.
Don’t forget that eighty-five per cent of motor failure can be traced to electric trouble; either in the battery or the coil or the wiring or the plugs.
Don’t try to start the motor with any “lead” on.
Don’t run at too high speed just to show off, as you might burn out bearings.
Don’t fool with adjustment of spark coil. The vibrator is properly adjusted at factory and seldom needs readjustment.
Don’t take engine apart unless absolutely necessary and if you have to do so to get at inside of crank-case, simply tip cylinder over, not removing piston.
Don’t expect to get best results from an engine working on a shaky foundation.
Don’t forget to turn down grease cups every hour or so, forcing grease upon your bearings. Be sure there is plenty of grease in the cups.
Don’t forget that extra can of oil if you are going on a long trip.
Don’t try to start engine with the draining plug out of the bottom of crank-case or with drain cock open.
Don’t try to use batteries after they are played out; it is a good plan to purchase an extra set of batteries after the ones you are using have been in service about two months. We have seen batteries that will run for six months and still be in good condition; but we have also seen them played out in a few weeks.
Don’t forget to open sea-cock to pump, if you have one.
Don’t try to start without first making sure that the spark lever, timer or commutator is retarded.
Don’t try to start without the switch turned on.
Don’t try to start an engine which has a reverse gear or clutch, without making sure the lever is set neutral.
Don’t screw the spark plug in too tightly but only just enough to prevent leakage and hold firmly. You may want to take it out again.
Don’t put your wrench on upper nut on spark plug when plug is in cylinder. You may destroy it.
Don’t use other than the best gas engine oil. The best steam engine oil will not do.

Don’t think that because too much oil is bad that too little is better.
Don’t forget to throw out the switch or pull the button, and put in your pocket when not running.

Don’t run engine unless the pump is working.

Don’t expect engine to run if wire connections get loose, batteries weak, spark plug dirty or wire poorly insulated.
Don’t put your face close to an opening in gas engine when switch is on, or to see the spark take place.
Don’t run an engine if a hammering or knocking noise is heard; find the trouble.

Don’t forget to turn on gasolene cocks both at tank and engine before starting.
Don’t think it waste of time to clean off ignition points occasionally.
Don’t wear yourself out cranking an engine; if it does not start after three or four turns after priming something is wrong.
Don’t think that a thump, pound or thud about your engine is always due to some trouble in the cylinder or connecting rod.
Don’t put a check valve between carbureter or vaporizer on a three-port engine.

Don’t use 90-degree els, when possible to use two 45-degree, especially on exhaust pipe.
Don’t forget that a union on each pipe as near to end as possible is good practice.
Don’t try to start with carbureter throttle entirely closed or entirely open.
Don’t adjust the carbureter as soon as the engine works badly; it may be poor ignition, poorly seated valves, poor water circulation, etc.
Don’t expect gasolene to run up-hill.

Don’t expect an engine installed below the water line with underwater exhaust to run, unless the exhaust pipe is carried above the water line, before entering the water line, and an air valve or relief cock placed at highest point.
Don’t think a dirty, rusty engine will run as well or last as long as a well-kept one.
Don’t forget that success or failure depends upon yourself.

Don’t forget to turn off the gasolene cock when not running.

Don’t forget to fill gasolene tank.

Don’t forget to draw water out of cylinder in cold weather.
Don’t wipe engine while running.
Don’t use too much gasolene; more power is developed with smokeless mixture.
Don’t pile anything on batteries.
Don’t be afraid to fix your engine.

Don’t get excited, but go carefully.

Don’t trust wire screen strainer, but use chamois skin, and save trouble. If chamois skin is not handy, use handkerchief.
Don’t look for the opening in your gasolene tank or a leak with a match.
Don’t reduce the size of pipe after leaving the engine.
Don’t have any more turns in exhaust pipe than possible.
Don’t see how close you can run to another boat.

Don’t cut in ahead of a ferry boat or any other boat just because you have the right of way. They may not respect any rule except the rule of might.
Don’t forget that all sail craft, big or sjnall, have right of way over power craft.
Don’t forget to offer assistance to a boat in distress, and always ask it or accept it when offered when in distress yourself.

Engine Troubles And Remedies

13 Oct 2011 at 22:16

captain

How to build a boat

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A thorough understanding of the engine will often enable the owner to prevent trouble. Most engines have their own peculiar idiosyncrasies and the conscientious owner will carefully study his motor and ascertain the conditions necessary for its operation. When he is thoroughly familiar with it, if he cannot always prevent trouble he will be better able to detect and rectify it.
Engine faults, causing deficiency of power or inability to start, may be divided into three classes: Mechanical troubles, ignition troubles and carbureter troubles, or those due to faulty mixture.

Mechanical troubles include those that may be included under the heads of Poor Compression, Weak or Broken Valve Springs, Valve Timing and Pipe Obstructions and Leaks.
The great majority of engine troubles may be charged up to ignition. Ignition troubles are easily distinguished from those due to imperfect mixture. If the spark fails or is very weak, the charge is not ignited at all. If the sparks are regular, too much or too little gasolene in the mixture will make the engine run weak, but there will be no misfiring unless the mixture is very bad indeed. If the explosions which occur are reasonably strong, the cause of misfiring is to be looked for in the ignition.

If the engine owner or operator has familiarized himself with the principles and adjustment of his carbureter, or mixing valve, he will soon learn what to do in case of trouble with the engine when the symptoms indicate defective mixture.

The most common engine troubles and their symptoms, may be very briefly summed up as follows:

Failure to Start.

Too much or no gasolene, or no spark at the plug.

.

Not enough gasolene; or too late a spark.

Pounding.

Generally a loose flywheel, or too early a spark.

Failure to Reverse.

Probably too much gasolene turned on, speed not caught right, or weak batteries.

.

Defective spark plug, water in cylinder, poor contact at cam, weak batteries, too much gasolene, or vibrator of coil sticking.

How to Remedy Troubles.

In the following pages the symptoms of and remedies for all the troubles likely to be experienced in operating a marine gasolene engine are clearly indicated.

Leaks.

See that gasket is sound and no leakage from crankcase.
See that spark plug is screwed in tight, so there is no leakage around threads.
See that valves in carbureter seat properly.

Stops.

Regulate flow of fuel so there is no flooding or starving.

See that commutator is in tune with fuel supply.
See that spark is healthy, causing regular explosions.
See that cylinder is perfectly lubricated.

Failure in Starting.

If the engine refuses to start the following causes are possible:
1. Switch not closed.
2. Gasolene shut off; too much or not enough gasolene.
3. Broken wire.
4. Water on spark plugs.
5. Dead battery.

6. Grounded low tension igniter.
7. Carbureter primed too little or too much.
8. Water in carbureter.
9. Stale gasolene.
10. Weak spark or no spark at the plug.

If high tension ignition is used, turn the crank slowly and note if the coil tremblers buzz. If not, look for broken primary wire or dead battery. If ignition is by make-and-break, short circuit one of the igniters by snapping a wire or screwdriver from the outside connection to the engine, and see if a spark results. If the engine has only one or two cylinders, short circuit the (high tension) spark plugs to test the spark. To do this, touch a screwdriver to the cylinder, then approach it to the spark plug binding post. By doing this you will avoid a shock. The foregoing tests will indicate whether or not the ignition is at fault. If it is not, look for mixture troubles.

If the engine fails to start after several trials, too much gasolene may be feeding, which can be determined by opening the air-cocks and turning the flywheel around slowly with the switch on until an explosion takes place through the air-cocks, then close them and start as before.
It very frequently happens that an engine becomes flooded with gasolene by allowing it to stand with the gasolene valves open, so the gasolene can work in and lie in the base of the engine. It will then be difficult to start on account of the excess of gas which is formed. To determine this, open the cock at the bottom of the engine and turn the flywheel around until an explosion occurs.

Missing Explosions.

Defective or dirty spark plug, water in cylinder, poor contact at cam, loose connections or weak batteries, sticky vibrator on the spark coil. Sometimes caused by feeding too much gasolene. Occasionally the timer may give a poor contact and cause missing, which can be easily remedied by. putting in new contact pieces or stiffer springs.

Base Explosions.

Not enough gasolene. Turn on more gasolene and set the spark a little earlier.

Sudden Loss of Power.

If the carbureter has been giving good service and the mixture suddenly goes wrong, do not attempt to correct matters by changing the carbureter adjustment. Look instead for stale gasolene, for a sticking auxiliary air valve in the carbureter, or for dirt or water in the gasolene. If the carbureter has a wire gauze intake screen it may be choked with dust. If the carbureter floods, the float, if of metal, may be punctured, or if cork, it may have absorbed gasolene ; or the float valve may leak and cause dripping. If the weather has suddenly turned cold and the engine will not start, probably a little hot water poured over the carbureter will evaporate the gasolene and start the engine off as well as ever.

Loss of Compression.

Failure to hold compression may be due to leaky exhaust valves, leaky gaskets or leaky piston rings. An extra dose of oil on the piston head will make the rings temporarily tight in case they leak, and oil squirted on the gaskets or around the spark plugs will betray leaks at those points. The seat of a leaky exhaust valve will be pitted and burnt, and will show by its appearance that it seats on one side only.

The compression may become weak for lack of sufficient lubrication. When this trouble occurs it is a good idea to pour a little cylinder oil through the spark plug hole, then see that the oil cups are feeding properly. In old engines the compression may become weak from the wear of the piston rings. New rings should then be fitted, which, after a little running, should wear to a good fit and give better compression. The flywheel should spring back after being pulled up against the compression.

Pounding.

When a pounding noise is heard the cause is most generally a loose flywheel key. Sometimes pounding is caused by early ignition, due to hot spark plug or sticking of the piston. If a hot spark plug is the cause the engine will run after the switch is thrown off. If caused by a sticking piston the latter will stick tight after a little running under full load and stop the engine. Plenty of oil fed to the cylinder will overcome the sticking of the piston. If any pounding is heard stop the engine at once and locate the cause of the trouble immediately, as above.

Deficient Power.

Occasionally, deficient power in one cylinder may be traced to the valve spring being too weak or too stiff, or a broken spring will cause a particular cylinder to act badly. If the springs are too weak the engine will be noisy and weak except at low speeds.
A possible cause of deficient power is small or crooked piping, inlet or exhaust. Pipe elbows should never be used; all bends should be of easy radius, and the intake piping should be smooth internally.

Gasolene Feed.

It is very important to feed the proper amount of gasolene at all times. If too little is fed base explosions will occur, and if too much is supplied the engine will slow down. The best way to regulate the gasolene is to open up the throttle wide, put in the clutch (where a clutch is used) to give the engine a full load, then adjust the gasolene by gradually closing it off until the highest speed is reached; then close it still further until the engine commences to slow down or miss fire. Then opening the needle valve a little should give the proper mixture. A little practice will enable one to determine the proper point at which to set the needle valve, which, when once set, should seldom require further adjusting, but it is well to try it occasionally to see if the engine will not operate on less gasolene.
Troubles are sometimes experienced by not getting enough gasolene through the pipes, caused by the pipes being partially stopped up or the tank too low, which can be easily remedied.

Spark Coil.

The only delicate part of the spark coil is the contact points on the vibrator. These points are liable to become burned and stick, causing misfires. These can be examined occasionally, and if they show rough surfaces they can be smoothed up with fine emery cloth or a fine file. The vibrator can be adjusted by the thumb-screw so it will give a good spark. It is best to screw it down as far as possible, but with weak batteries it will have to be screwed back to give less tension to the spring.

Make-and-Break System.

The procedure in tracing an ignition fault, says Mr. Herbert L. Towle, C. E., will depend somewhat on whether the low tension or the jump spark system is used. If the former, the first step is to test the adequacy of the spark. Disconnect all the igniters (by opening the cut-outs, if there are any) and touch one end of the wire from the coil to the cylinder. If there are cut-outs, touch a screwdriver to the cylinder and to the bus bar connecting all the igniters. If no spark results, the trouble is in the batteries or in the wiring. Test the batteries with an ammeter or voltmeter. Dry cells should test 5 amperes or more on short circuit. Storage cells should test 1.8 volts each or more, on open circuit. Never test storage cells with an ammeter. If the batteries show proper strength, hunt for broken wires or loose connections. Possibly the wire from the coil may be grounded on the engine.

Sooted Igniters.

If a good spark is obtained on test, it is still possible that the igniters may be partly grounded by soot. If the igniter plates have two lava bushings, one of them may be cracked, or soot may have accumulated in the air space between them. With mica insulation, soot gradually collects between the mica leaves. A ground in any individual igniter will have the effect of grounding all the others, and the engine will not run at all. A partial ground due to soot in one igniter will cause missing in all the cylinders. To locate a partial ground, cut out all the igniters except one and run the engine on one cylinder at a time with reduced throttle. If several igniters are slightly sooted, missing will be produced as though one igniter was considerably sooted, but each cylinder when running separately will run all right. The only remedy is to take the igniters out and clean them thoroughly. To locate a completely grounded igniter, connect one igniter at a time, taking care that it is not making contact at the spark point, and short circuit it with a screwdriver. If no spark is produced it is grounded. Another symptom will be a spark between the wire to the coil and the igniter binding post when the igniter points are not making contact.

Jump Spark System.

If high tension ignition is used, first note by the sound of the engine whether missing appears to be confined to certain cylinders. If so, the cylinders at fault are quickly located by holding down with the fingers the tremblers of one or more of the spark coils. If all but one are held down the ‘engine will stop, if the last cylinder is not working. When the faulty cylinder has been traced, first note whether the trembler gives a clear buzz. This can be done by opening the pet cocks, retarding the spark, and turning the engine slowly by hand until the desired trembler buzzes. If the sound is not clear and steady, adjust the contact screw by turning slightly. If the spark is much feebler than that given by the other coils, but there is no arcing at the contacts and the trembler is adjusted as well as possible, the coil is probably short circuited and must be sent to the factory.

Sooted Plugs.

If the trembler and coil are all right, the spark plug is probably sooted. With some engines and some spark plugs, this is a very common occurrence, and the plug is the first thing to be examined. If the plug is clean, it is still possible that the porcelain is cracked internally. Try a new plug or exchange with the plug from some other cylinder. If the same cylinder still misses, investigate the cable for leaks due to water or to defective insulation.

.

If “synchronized” jump spark ignition is used i. e., a single coil and a high tension distributer the symptoms of different possible troubles will be substantially as above, with the exception that local misfiring can only be due to leakage in the spark plugs or spark plug cables, or to defective insulation in the distributer itself. The latter may be due to water or dirt or to metal particles, and should not appear if the distributer is kept clean. The trembler for such a system does duty for all the cylinders instead of only one, and its contact points therefore require frequent attention.

.

If the engine stops suddenly without warning, the cause is probably a broken battery wire. If it gives a few weak explosions before stopping, the cause may be a suddenly slipped timer, or the gasolene may have given out. Water in the gasolene will stop the engine very abruptly, but there are usually a few spasmodic explosions before it ceases entirely. If the explosions grow weaker for some moments before the engine stops, and if on priming the carbureter and cranking, the engine starts again but presently stops, the flow of gasolene to the carbureter is probably obstructed by dirt or fluff, which may be in the gasolene pipe, in the carbureter intake, or in the gasolene filter (if the carbureter has one). See if the gasolene runs down freely when the float is depressed. If it does not, disconnect the gasolene pipe at the carbureter. Most carbureters have a draining connection or petcock, where the gasolene enters, and by opening this, the accumulated dirt or water may be flushed out.

Preignition.

Occasionally, the explosions in one or more cylinders will produce a sharp metallic knocking quite unlike the muffled thump due to loose bearings. This noise is due to spontaneous ignition of the charge before the spark occurs, and is caused usually by incandescent particles of carbon on the piston head. This carbon accumulates gradually as a residue of the cylinder oil and requires to be scraped out once or twice in a season.

Dirt in the Carbureter.

When you have tried all other things and failed to remedy the trouble, look for obstructions or dirt in the carbureter or gasolene pipe. Do not say, “Oh, I know they are all right,” for you do not know until you examine them. A piece of waste, cork, chip, dirt, accumulations of paraffin or glue from gasolene barrels may work through the pipe connected to the carbureter, and while not stopping the entire supply will often cut down the supply, causing slowing down and back-firing, often stopping the engine, gradually filtering through and allowing the engine to start, but later giving the same trouble.

Test for Preignition.

On throwing off the switch, if engine continues to run the cause is preignition.

Removing Carbon.

Avoid trouble by using a good grade of gas engine cylinder oil. A good plan is to put about two or three tablespoonfuls of turpentine in each cylinder, and run the engine the same as you would when using kerosene to clean out the carbonization on piston cylinder and rings; do it after running, say, 200 miles or more, or at any time cylinders have heated or become carbonized. Kerosene is mostly used to clean out cylinder; either kerosene or turpentine will do.

Flooding Carbureter.

Flooding at the carbureter may be caused by dirt under the needle valve and sometimes can be removed by jarring the carbureter or pressing the float spindle against its seat and revolving, otherwise it will be necessary to remove the cover on the float chamber and lift the float out; the needle valve can then be inserted and moved around on its seat, thus removing the dirt. Be sure that the carbureter stands plumb.

A carbureter which drips continually when the engine is not running is hard to start, owing to over-richness of the mixture, especially if the engine has been shut down for a few minutes without closing the gasolene valve. If the gasolene level is more than 1/16 or l /% inch below the spray orifice it will not be as easy as it should be to run the engine slowly.

Carbureter Adjustment.

Irregular explosions may be caused from either improper mixture, or defective spark. The mixture can be adjusted by the needle valve at the bottom of carbureter. If the gasolene is turned off too much it may cause back firing, or base explosions, and therefore must be opened up again slightly. This rule should be borne well in mind. After the carbureter is properly adjusted it seldom requires any changing. Any defect in spark will be located in the coil, plug, battery, or timing mechanism.

Installation Of Engines

13 Oct 2011 at 22:15

captain

How to build a boat

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As a rule, it may be said, the installation of a marine gasolene engine is a comparatively easy matter. By reference to the diagrams and instructions presented in the following pages, which apply to well known engines of typical make, the amateur will be able to install an engine properly in a canoe, rowboat, launch, flat-bottom boat, sailboat or yacht without special tools or expert experience. These instructions or those furnished by the engine builders in the case of engines not referred to here should be read with care, and each part of the work should be done in the order named. After each part has been done the work should be examined to see that it has been done properly before taking up the next part.

In selecting practical instructions for installing a, few well-known engines, the object has been, not to show any discrimination in favor of the engines mentioned, but to cover by actual illustration all the points likely to arise in installing an engine of any make. There are many good, reliable engines in the market besides those named^ in these pages and the power boatman has a wide range of choice. No matter what engine he may select, how- ever, he will find among the instructions given below many general points applicable to all engines alike and these are the points most essential to observe. The installation features peculiar to any particular engine are always clearly indicated by the manufacturer or sales agent.

It is impossible to get satisfactory results from your engine unless the foundation is right and the engine is properly installed. The foundation should be so constructed as to take up the thrust and distribute the engine vibration over a large part of the bottom of the boat. The following is a foundition recommended for the Ferro engine. It is simple and easily installed and yet fulfills all the essentials of a good foundation:

It is assumed at the outset that the skeg or shaft-log is in place ready to receive the propeller shaft. Stretch a string so that it passes exactly through the center of the shaft hole and fasten it in this position, having the forward end a little in front of where you plan to place your engine.

This string will be about s/g inch higher than the level of the top of the engine bed (the thickness of the crank-case flange). Another method is to place a piece of gaspipe in the shaft hole, making it long enough to reach forward of the engine bed. When this pipe is leveled up it will give you almost exactly the level of the engine bed.
Get out two fore-and-aft pieces (AA) first. All the foundation timbers should be of oak if possible, or other hard wood if dak, is not obtainable. For engines below about 15 H. P. two-inch stock can be used, but pieces three inches thick should be used for engines over 15 H. P. Lay off on the bottom of the boat the position of the fore and aft logs, having the inside width between them about an inch less than the width between the crank-case holes as shown on the engine dimension sheet.

The bottom of these timbers should of course be shaped to conform to the bottom of the boat in the position laid off. They should be laid on top of the ribs and not notched out to receive them. The height of these fore-and-aft timbers can of course be determined by leveling up a straight-edge on top of the string or pipe and measuring the height from this to the boat ribs, allowing about 2 inch in using the wire and the thickness of the pipe in using that.

The distance L-M, the engine bed proper, is of course determined by the length of the crank-case, and must be increased when using the reverse gear, as shown in an illustration, but how long the after-end of the log (M-N) should be must be determined by circumstances. It is a good plan to make it nearly or quite as long as the forward distance (L-M) and in case of a single-cylinder engine it will do no harm to have it even longer, provided you place your engine in such a position as to make this possible.
Remember a single-cylinder engine requires a heavier bed proportionately than a multiple cylinder engine.

Notch out underneath the forward ends of the fore-and-aft timbers about two-thirds of their height to receive the forward crosspiece (B) as shown in the diagram. This crosspiece should be cut to extend the extreme width of the boat and should be carefully shaped to fit the bottom of the boat at this point.

Reverse Gear on Engine Bed.

Another crosspiece (D) ties together the after ends of the fore-and-aft timbers, being notched out at both ends to receive them. This piece can run the whole width of the boat and should be full height and shaped to conform to the bottom of the boat. In installing engines of 15 H. P. or over, it is also well to add a crossbrace between the fore-and-aft timbers just forward of the pump and of as great height as possible and yet give plenty of clearance. Crosspieces should be about l/2 inches thick for the smaller engines and 2 inches for the larger ones.
After all the timbers are got out they should be nailed down temporarily and the engine and shaft put in place to test the foundation and see if it is of the proper height and slant so the shaft will be in line when the engine is in place. If ribs do not come under the engine bolt holes, put in extra ones that will, so you can bolt through them. If this test shows the foundation to be right or nearly so, the logs may >be bolted down as shown in the diagram. Note that all crosspieces are bolted through the keel and the fore and aft pieces bolted through rib and planking at intervals of every other rib. In no case should bolts be fastened through the planking only, as this will work the planking loose. Put good-sized washers coated with white lead under the bolt-heads on the bottom of the boat so as to prevent possibility of leakage. Note that the crosspiece is lagged to the fore and aft pieces in front and the middle cross-brace lagged through them from each side.

With the foundation thus fastened in place, the engine is now ready to be installed. The final lining up should be done when the boat is in the water, for then it changes its alignment somewhat. If your boat has no skeg, but an outboard bearing, place your inboard stuffing-box on the shaft, but don’t fasten it in place until you have lined up your engine and shaft. But if your boat has a skeg, put your stuffing-box outside in place first and see whether the shaft turns freely before it is fastened to the engine. If not loosen the box and pack around it until the shaft turns freely, then screw the box in place. The hole in the shaft log should be 4 mcn larger than the diameter of the shaft. Fill with white lead between the stuffing-box and its seat.
After putting the engine in place fasten half of the flange coupling to the propeller shaft and hold this up against the flange coupling on the end of the engine crankshaft. Note whether the two halves come together evenly all the way around. If not, move the engine side- ways or pack up, or cut away under one end as the case may be until four strips of paper placed between the two parts of the coupling on opposite sides are held with even tension as the coupling is pressed together. Now bolt down the engine in the four corners and try the strips of paper again. If all are held evenly, bolt the engine down permanently; if not change the position of the engine as before until the right position is found.

This done, take the spark plugs out of the cylinders and note how much force is required to turn the engine over. Then bolt the coupling together and again try turning the engine over. It should turn as freely as before. This is important. The engine must turn as freely when coupled to the propeller shaft as when uncoupled.

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If it does not, something is out of line and must be changed or serious loss of power and perhaps worse trouble will result. Unbolt your coupling and go carefully over your alignment again as described above. Pack the stuffing-box between the nut and body with hemp or candle wicking soaked in grease and screw up just tight enough to stop water leak but not enough to bind the shaft.
To Install a Reversible Propeller Before connecting shaft to engine coupling locate the lever, quadrant, thrust and clamp collars and inside stuffing-box. Place quad- rant with pin towards the engine. Allow space between fork and stern bearings for moving the lever forward to unlock the header when pin is removed from the forward end of quadrant. On long shafts place bearings every five feet along the tubing. Be sure the shaft does not bind in any way. Use grease between shaft and sleeve and in blade joints. Place the reverse lever in a vertical position with tips of blades square with shaft.

Then securely bolt clamp collars against center thrust collar. The blades will then have the same pitch whether full lead ahead or reverse. To remove the blades, take out the pin in the forward end of the quadrant, moving lever forward until the blades are unlocked from fork, then un- screw the blades from the hub.

Bore the hole for your water intake in such a place that the piping between the pump connection and intake will have no sharp turn in it, and never reduce size of this pipe. A short piece of hose can be used as a joint for flexibility, but we would caution you against making this hose connection too long, as you will have leaks and pump trouble. As good an intake connection as any is to take a short piece of gas pipe threaded to take a lock nut on the inside and one on outside of planking. Pack the lock nuts inside and out with two or three turns of candle wick soaked in white lead. It is well to connect a cut-out valve to the intake connection. Outside this in-take connection fasten the scoop, putting the fine wire screen inside and turning the scoop opening forward in fastening it to the bottom of the boat.

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The following instructions for installing the well known Lamb engines, built by the Lamb Boat & Engine Company, of Clinton, Iowa, are remarkable for clearness and conciseness and contain many excellent hints applicable to the installation of engines in general:
Keelson and Bilge Keelsons

In constructing a power boat, a keelson is usually notched over the ribs and bolted to the keel. In addition to this, bilge keelsons or stringers are recommended, one on either side, and running nearly parallel to the keelson.

These keelsons also should be notched to fit over and securely fastened to the ribs and planking. The keelsons, coming under the motor foundation timbers and over a number of ribs, distribute the strain over a large area and contribute largely to the stiffness of the structure.
Shaft Hole The shaft hole should be bored the size given in table of motor dimensions in the catalogue, taking care that it is of such a pitch or angle that the propeller will be entirely submerged, and that no part of motor bed or flywheel will come in contact or touch the inside of boat aside from the foundation timbers.

With properly constructed deadwood, there is no shaft hole lining needed except where the stuffing-box is placed on the inside of the boat. With the last named arrangement a brass or iron tube may be used, the stuffing-box fastened to the inboard end and the stern bearing to the outboard end.

The shaft hole being bored, stretch a fine line through the center of it; fasten the outboard end to a stick nailed to the stern of the boat; make the other end fast inside of boat; go over the line carefully and see that it is in the exact center of hole throughout its length, and if the shaft hole has been properly bored, a plumb-bob held beside the line should point to the center of the keelson, provided the boat sits level.

The face of the stern-post must be absolutely smooth and at exactly right-angles with the line which has been stretched where the center of the shaft should be.

Foundation

In the table of motor dimensions in the catalogue sees distance from the center of the shaft to the bottom of floor flanges. This distance being known, the foundation timbers, which should be of good sound oak, should be securely fastened to keelsons at the given distance from the line, and at the same pitch or angle as the line.
These foundation timbers may run either athwart ship or fore and aft; in either case they must be securely fastened to every timber and plank over which they pass. The table of motor dimensions gives all necessary measurements, but it is well to check your measurements over when you receive the motor.

Placing Motor

Place the motor on the foundation at the proper position fore and aft, and in line with the center of the shaft. The shaft now being in place, compare the faces of flange couplings and see that their faces come together fairly. The least variation at this point, if allowed to remain, will cause undue friction and heating.
With motor securely bolted down and faces of flanges on the couplings coming up perfectly fair, you may feel reasonably sure your motor and shaft are in line. This is important.

Stern Bearing and Stuffing Box

Bolt the stern-bearing to stern-post with a film of white lead between. See that the shaft turns perfectly free after the stern-bearing is fastened to place. If it binds the shaft, it would indicate that the face of the stern-post is not exactly at right- angles on the shaft and must be dressed off until the shaft works free.

If a log is used, the inside stuffing-box is bolted to the inboard end, after having squared the end the same as described for the stern-post. If no log is used, insert a sleeve, one end of which screws into the stern-bearing, the sleeve being long enough to extend into the boat far enough to admit of the stuffing-box being screwed on the inboard end.

Piping

Use care in cutting threads on all pipes so that they will make up tight, using white lead on all joints of water pipe and soap on all gasolene connections.
Make all pipe runs as direct as possible, avoiding elbows and bends. Water pipes should be all brass where the boat is used in salt water, but for fresh water, common iron pipe will answer.
For the sea-cock or intake to the pump, the pipe should have long running thread cut on the end intended to go through the planking. The hole should be bored through the bottom of the boat small enough so that the pipe will screw tight into planking. Have a lock-nut both inside and out after the pipe is screwed through the planking far enough to admit of a full tread on the lock-nut outside. Put a few turns of white-leaded candle wicking under the lock-nuts and screw down firmly, tacking a dish screen over the end of pipe to keep all foreign matter out of the check valves.
A stop-cock should be placed just inside of the boat that the flow of water may be regulated to suit conditions. It is also advisable to place a tee just above the stop-cock, taking the water from the side of the same with a plug in the end. In case of pipe getting clogged, the plug may be removed and a small rod of wire used to clean same.

The discharge from the water-jacket overboard should be above the water line if possible and should be fastened as described above for the sea-cock pipe; all water pipe to be no smaller than the openings in or out of the motor for same, and larger will do no harm.
pipe should be of copper, tin, brass or lead, never iron, and should be run from the tank to the carbureter as directly as possible along the keelson.
See that the gasolene pipe is thoroughly cleaned before making up, as a very small amount of dirt or scale will clog the carbureter.

Gasolene Tank The gasolene tank should be placed as high up in the bow of the boat as possible so that the gasolene will have sufficient head to flow to the carbureter good and strong.
The gasolene tank should have a strainer over the out- let opening, inside of the tank. A hole should be cut through the deck to correspond to the filling plug in the tank and the gasolene should be thoroughly strained when filling the tank. Chamois skin makes the best strainer as no water will pass through it. The tank must be securely fastened in the boat to avoid straining of joints in the gasolene pipe, should the tank shift.

Exhaust Pipe

Either of two styles of mufflers is furnished with Lamb engines. The one most to be desired is of the automobile type, and can only be used on boats with a fixed roof. The mufflers are light and are securely fastened to the roof, the exhaust pipe from the motor running up through the roof to the muffler, with sheet-iron hood running from the motor to and through the roof, covered by a cone to shed water. This hood should be two inches larger than the exhaust pipe, thereby furnishing a one-inch air space around the exhaust pipe, which is sufficient to carry off the heat from the exhaust pipe.

The other style is the stern muffler, to go under the stern deck, with outlet from muffler running out from either side of the stern. This style of muffler necessitates the running of the exhaust pipe under the floor of the boat to the stern, connecting to the muffler and then out as previously described.

Where this type of muffler is used it is advisable to admit a small amount of the discharge water from the water-jacket into the exhaust pipe to keep it cool. There should be a valve placed in the water pipe to the exhaust pipe that the amount may be regulated, as too great an amount of water in the exhaust pipe tends to choke same and to check the speed of the motor.

Batteries

Lamb motors are regularly furnished with two sets of dry-cell batteries. These should be placed in a dry place in the boat and connected as shown by the wiring chart accompanying each motor. Where dynamos or magnetos are used, one set of batteries are cut out and the generator wired in their place. A dynamo or generator will give much better satisfaction if used in connection with a storage battery.

Wiring

If there is one thing more important than another in motor installation, it is the wiring, which should be done carefully and well. All wires should be visible and above floor if possible; for instance: We will explain the method of wiring the Lamb 4-cylinder 4-cycle motor. The wiring chart fully describes or shows the manner of connecting batteries to the spark coil and from the spark coil to the motor; the circuit-breaker or timer has four binding posts marked 1, 2, 3, 4. These indicate the post to run the primary wires to for each cylinder, for instance : Taking one end of the coil as No. 1, run the primary wire from this end coil to the binding post marked (1), also secondary wire from same coil to the spark plug on the top of No. 1 cylinder on the motor.
Run wires on numbers 2, 3, and 4 cylinders in the same manner. Having completed the wiring as described, remove spark plugs from the cylinder heads and lay them on top of the cylinder, so that they make contact the same as if they were in place. Now beginning with No. 1 cylinder, place piston on the upper center after having completed the compression stroke. Be sure it is the compression stroke.

Now set your timer to spark at this point and you should have spark on No. 1 spark plug. Then try the next cylinder, which should be No. 3; be governed by the numbers stamped on the timer for the sequence in firing.
After timing each cylinder perfectly your motor should start readily.

Installing a .

If the motor is to set in a boat, allow at least three inches under the rim of flywheel so as to give the hand plenty of clearance in starting. If possible set the motor so that there will not be over one and one-half inches pitch to foot of propeller shaft. After the motor is set turn the carbureter connections so that it will stand plumb, otherwise the valves may not work freely. All circulating pipes for salt water should be of brass. The gasolene feed pipe should be of brass or copper. Great care should be exercised in making up the connections for the gasolene supply, so that there will be no possibility of a leak. Make up all threaded joints with shellac or common bar soap and solder. Exhaust pipe is usually of galvanized iron. Avoid placing the exhaust pipe nearer than one inch to any woodwork two inches would be better. Cover if possible with asbestos. Set the gasolene tank above the level of the carbureter; three or four inches is enough. In a boat the tank is nearly always in the bow, as tnat is the highest point. For auxiliary installation we would recommend placing the tanks aft on deck under the lockers or seats if possible; this will avoid the necessity of running the gasolene pipes through the cabin or other inclosed parts of the boat. In connecting the gasolene supply use two stop-cocks, one at the tank and one at the engine, also use two unions in the same way; then either tank or motor may be removed without removing the other. All air must be forced out of the gasolene pipe before motor can be started. All water connections should have stop-cocks or seacock with aircock to drain all piping. Be sure that the inlet has a suitable screen to cover the opening to keep out dirt and other foreign matter. Water jacket and pipes must be kept drained in cold weather when not in use.

Exhaust Devices

13 Oct 2011 at 22:14

captain

How to build a boat

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The noise and odor of the exhaust gases escaping from a gasolene motor being continuous and objectionable, some device is necessary to deaden them. The device in universal use on land for this purpose is an air muffler and for marine gasolene engines the air muffler is also often used. It is usually made in the form of a cylindrical chamber attachable to the exhaust pipe. It is fitted inside with baffle plates, against which the exhaust gases expand and then escape into the air at the open end by the way of an attached pipe leading through the side of the boat at a point above the water line.

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The air muffler serves best, however, on land, for automobiles, etc. In boats, different conditions exist. On account of the well known condensing action of water and consequent reduction in pressure where cool water is mingled with the exhaust gases, it is possible to both silence the noise and increase the power developed by the engine. Besides, as the water is being pumped through the cylinder jacket constantly”, an automatic feed to the exhaust pipes may be had, keeping them almost cool to the touch. The first form of muffler consisted of a water jacket around an air muffler through which the waste, cooling water was led and then piped overboard. Then another method was tried, namely, running some of the water directly into the exhaust pipe, between the engine and the muffler. In this case it was necessary to make the muffler water-tight, while the air muffler is not water-tight. The immediate result was a great reduction of noise and pressure in the exhaust. It required careful regulation of the water, also a drain for deposited water in the muffler.

The Under-Water Exhaust.

The under-water or submerged exhaust is an effective way of muffling the exhaust noises, but it must be installed properly to be a success.

A submerged exhaust should never be put in a boat without a relief valve leading to a free opening, so that when starting, or at any time that it may be necessary, the exhaust may be turned out into the open air.

The depth below the water and the location of the outlet on the bottom of the hull are dependent greatly upon the general lines of the boat.

Choice of .

All boat owners are interested in the question, what method of discharging the exhaust in motor-boats is most efficient in reducing the noise and odor without impairing the power of the engine or interfering with the interior arrangement of the boat?

This question was asked of its readers recently by the popular magazine, , and the prize-winning answer by Mr. L. Kromholz, of New York City, was as follows:

The choice of a muffler must be made from a study of the circumstances governing each case. That an arrangement of apparatus gives complete satisfaction on one boat does not necessarily mean that it will be equally successful on another.

For open launches an expansion chamber and a large pipe leading aft to the stern and out under water is a good and simple method. The difficulty of water getting back into the pipe and filling the cylinders, can be overcome by running the exhaust pipe in a straight line (under the side seats) from the motor to the outboard fitting. This will be well above the waterline and have enough pitch so as to drain easily. A relief cock should be fitted to assist in starting the motor. The loss of power, if any, will be slight, in fact in some cases .it is claimed more power can be obtained with the submerged exhaust than without it.

On high speed runabouts all of the cooling water from the motor can be let through the muffler, but the piping must be in a straight line without any quick bends where the water is likely to collect and choke the exhaust. A completely water-jacketed exhaust from the motor to the outlet at the stern is an efficient device. The straight lead aft to the stern will cause but little back pressure if the pipe is of good size.

A water-jacketed muffler or one with the cooling water running through it with the exhaust outlet under water and near the engine, is a good arrangement for cabin cruisers. Another way would be to wrap asbestos around the exhaust pipe and lead it under the seats or berths in the cabin, under the flooring in the cockpit to the muffler in the stern and out. In this way the piping would have a fairly straight lead with no sharp turns and would not interfere with the accommodations to any extent. Letting the exhaust out at the stern is good practice, as there is hardly a chance of the odor being blown over the occupants of the cockpit.

On the larger motor boats or yachts the best and most popular way is through water-jacketed mufflers in a false funnel or stack. But while a stack will improve the appearance of many yachts it cannot always be made a thing of beauty.

Sharp turns; bends or ells in the exhaust pipe should strictly be avoided as they decrease the speed of the boat a great deal.

Another experienced boatman, Mr. J. B. Sadler, of the , Norfolk, Va., also writing in Motor Boating, advocated the under-water method of muffling as follows:

For reducing the noise and odor of the exhaust in motor-boats and at the same time increasing the efficiency of the motor, the submerged exhaust system is without an equal.

By this system the exhaust is conducted from the motor to the expansion chamber, which must be located above the load waterline of the boat and from thence to a special fitting or nozzle, located in the bottom or side of the boat below the waterline.

As it is desirable that the flow of the exhaust through the exhaust nozzle be continuous, the expansion chamber must be placed between the motor and the nozzle, and should have at least six times the cubic capacity of the motor cylinder.

Before the exhaust passes overboard it must be cooled and contracted to its original volume, otherwise the contraction will take place beneath the boat and result in an annoying jar to the hull. To accomplish this, the general practice is to lead a part of the circulating water into the top of the expansion chamber or the exhaust pipe leading to it, but as the circulating water is somewhat heated, it is better to pump cold water direct.

The pipe leading from the expansion chamber to the exhaust nozzle should be larger than the exhaust pipe, and the exhaust nozzle should have the same area as the enlarged pipe.
The exhaust nozzle should point aft and be located away from the propeller, for if located in front, it tends to slacken the speed of the boat.

To facilitate starting the motor and prevent water being drawn into the engine cylinder in case of back- fire, a three way cock should be placed in the exhaust line. This cock should be so arranged as to have the exhaust opened to the atmosphere and closed to the sea when starting the motor. The pull exerted on the exhaust of a boat equipped with the submerged exhaust system, has the effect of increasing the speed of the engine. In some cases this increase has been as much as 50 revolutions per minute.

Form and Strength of Hull

13 Oct 2011 at 22:14

captain

How to build a boat

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The general principles underlying the work of the boat-builder and the methods whereby these principles arc carried into effect, are not difficult to comprehend.
The main objects of the builder are to realize the desired form and to provide the necessary staunchness and stability in his craft. In other words, form and strength are the main objects to be attained.

The form of the boat is a matter of design and involves geometrical principles and the study of such matters as utility, safety, appearance and air resistance. The amateur who builds his boat from patterns already prepared for him has little or nothing to do with the matter of design, since that was settled for him when he chose his model and bought his patterns. To realize the desired form, he has simply to follow the patterns.

The provision of the necessary strength in a boat is, however, a matter of mechanics and involves not only the selection of proper materials and the use of good workmanship, but the observance of sound mechanical principles to overcome the strains and stresses to which the beat structure will be subjected.

There are secondary matters, of course, to be considered before the boat is completed for use, but these relate mostly to the boat user’s convenience or comfort and depend a good deal on personal taste. It is unnecessary to dwell on these secondary matters, which may be left to the individual boat-builder, and we can therefore confine ourselves here to the realization of the form desired for the boat and the provision of the strength required.

It should be clearly understood that while these main objects are separate and distinct, they must be regarded together in the attainment of the result desired, which is to realize both objects with the same set of structural members.

Compromise Stern Motor-Boat.

The actual form of the surface of the hull depends entirely upon the outer planking or skin. To assemble this planking in the form desired an inner frame of some kind is necessary, over which the planking may be bent and secured in shape, also some form of internal stiffening to assist the planking in preserving the desired shape.

Thus, we must have these three factors in boat construction:
(1) An internal straightening framework.
(2) Frames or molds over which the planking is bent to the desired form.
(3) The outer skin or planking.

In practical boat-building two different methods of construction are employed. The first is a common method of building small craft, such as rowboats and the smaller motor-boats and launches. In this method the frames over which the planking is bent are temporary wooden molds and their object is fulfilled when the planking is put together in the proper form for the outer skin of the boat.

In the second method, used for the larger motor-boats, a framework composed of various members, including frames and cross ties or deck beams, is first constructed and set up to form a sort of skeleton of the boat model desired. The planking is then bent over and secured to this framework to form the outer skin and the framework thereupon becomes an integral part of the boat.
In building a boat from knock-down frames, as described elsewhere, these frames when set up constitute the permanent framework referred to above and it is no inconsiderable part of the entire construction of the boat. In other words, the use of knock-down frames saves the amateur builder most of the heavy carpenter work, besides assuring him of securing the form desired.
We may call the first method of boat-building the mold method and the second the frame method, it being clearly understood that molds are for temporary use only, to determine the form of the planking, while frames form a permanent part of the boat structure.

Provision of .

In providing the necessary strength for the boat hull, it is well to remember that strength is required in three different respects, namely, Longitudinally, transversely and locally.
Longitudinal strength may be defined as the capacity to resist bending along the fore and aft lines of the boat, such as hogging or sagging of the hull as a whole.

Transverse strength is the ability of the structure to resist bending or distortion to right or left with reference to the fore and aft axis, in other words, to resist transverse strain or the strain produced in the planking or other member by a force operating at right angles to its length.

Local strength is the capacity of the various members of the hull to resist stress exerted at any particular point; that .is, such a stress as might injure the hull at that point, but might not produce any distortion of its general lines.

In a boat without permanent frames or internal bracing, the planking is the principal factor which secures longitudinal strength. Various supplementary factors are required, however, to secure the necessary stiffness of the hull as a whole and these may include the combination of the keel and keelson, the sheer strake, stringers, clamps, and fender pieces or strips. The various positions in which these appear are illustrated. They are not usually all found in any one boat, though some are common to all designs.

In the provision of transverse strength the planking with its internal framing forms the principal factor, thus serving a double purpose, namely, determining the form or shape of the boat and providing a good deal of the strength required in the structure. The top sides of the boat, which are the weakest parts of the hull, may be strengthened by the use of deck beams or stringers, which prevent the sides from opening outward or collapsing inward, either of which by changing the form of the boat would destroy its general effectiveness. Where deck planking is used this adds to the transverse strength as opposed to inward strain. Though this planking is not often relied upon for the purpose, it likewise adds to the longitudinal strength of the boat and may be regarded, therefore, as one of the factors, though not an important one, contributing to the general stiffness of the decked hull. The flooring laid in the boat likewise contributes its share to the transverse strength, giving additional stiffness along the keel and bottom of the boat and forming a support for the lower members when these are subjected to transverse stress.

Turbine Boat Shallow Draft.

As far as local strength of the various members of the hull is concerned, but little special attention is usually required apart from the use of good materials, especially sound timber. Near the bow, however, where the sides of the boat may come in contact with the dock or other craft, also beneath the engine and at the stern where the propeller shaft requires support, special construction is needed to secure local strength at these points.

At the bow of the boat and in other points local strength is usually secured by means of chock or angle pieces, as will be seen in our illustrations showing longitudinal sections of motor boats. The sides of the boat may be strengthened by means of special fender pieces or strips. The part of the boat beneath the engine is strengthened to perform its duty usually by a special foundation of longitudinal timbers or of steel, attached to the structure of the boat in such away as to distribute through the hull the local stresses occurring through the running of the engine. The methods in use for this purpose are clearly indicated in the chapter devoted to the installation of engines. Generally speaking, it may be said here that the engine foundation should be long and large enough not only to provide the local strength required, but also to distribute the stresses properly.

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