Read an Excerpt
How to Build Wooden Boats
With 16 Small-Boat Designs
By Edwin Monk
Dover Publications, Inc.Copyright © 1992 Dover Publications, Inc.
All rights reserved.
THERE IS A certain fascination about boatbuilding, in watching a boat gradually take shape, and this particularly so when the results are through your own efforts. I often wonder if the amateur builder does not derive as much pleasure in the construction of his craft as he does in the use of it. It is at any rate a good hobby or pastime, and the man who builds his boat doubtless gets a bigger "kick" out of boating or yachting than does his brother who pays someone to build it for him.
It is the purpose of this book to present to the amateur boatbuilder a wide variety of small-boat designs and a clear explanation of small-boat construction in general, with particular reference to the designs herein. There is a much better opportunity to explain construction methods and detail in a book of this sort than in magazine designs, where space is limited and construction methods are repeated with each design. Many of the published "how to builds" are excellent, and the methods described and illustrated here are applicable to all of them. These methods and details are not impractical or devised by a novice, but are backed by extensive first-hand experience in small-boat construction and design, and many of these methods are in every-day use in the boat yards of today.
In the plans herein the purpose has been to produce a nice-appearing design that in every way looks the part, but with simplicity of construction always kept in mind. No attempt has been made to cover such subjects as rules of the road, seamanship, etc., and many other things sometimes included in a book of this sort. Some of these are useful, but can be found in other sources.
Building from Other Plans
Probably the best procedure would be to select as a guide some design shown here that closely resembles the construction of the boat in mind. If the boat is best erected upside down, a set-up line will have to be established, as it is seldom shown on other plans. This is, however, a simple matter and probably the only conversion necessary.
The Round-Bottom Boat
This construction is considered a bit difficult for the amateur, although the professional boatbuilder generally considers the round-bottom construction as easier. This book is not primarily intended to cover this type of boat, but can be of much help, and a separate heading in last part of the text will show its applicability. The clinker or lap-strake boat had best be left to the professional small-boat builder.CHAPTER 2
EACH LOCALITY HAS its own boatbuilding woods, the choice of which is governed somewhat by proximity of supply. Oak is probably the only wood universally obtainable for small-boat construction. For this reason the builder should be allowed a great deal of latitude in his selection of materials, and to aid him in this as many timber varieties as possible have been touched in the following specification. In the accompanying plans a certain species has been specified for each particular place or member, but this is intended merely as a guide. Boat lumber may be roughly divided into two classifications, which are: framing lumber, including that suitable for keel and stem; and planking lumber, which should include gunwales, stringers, and clamps.
To be suitable for framing its first requirement, aside from strength, is ability to hold fastenings. Therefore it should possess a certain hardness and closeness of grain. As it is generally in narrow widths a tendency to twist or warp is not a serious defect. As small boats are well ventilated, having very few dead-air spaces in them, there is little danger of dry rot, provided a boat is given a reasonable amount of care.
For planking purposes the lumber should bend easily and stay put after fastening; that is, it should not have a tendency to warp or to curl up at the edges. For this reason vertical grain is always ordered for the top sides at least. Hardness or ability to hold fastenings is not required, as all fastenings are through fastenings.
Weight is often quite a factor in the choice of materials, particularly so if the boat is to be a racing hydroplane or outboard, and for purposes of comparison the weight per cubic foot of most boat woods is given in the following table:
The following is a general classification of boat woods as to purpose for which they are used in small-boat construction.
Keel.—Oak, mahogany, Douglas fir, yellow pine, teak, and Alaska cedar.
Stem.—Generally of hardwood, oak, mahogany, teak, and bagac.
Planking.—The cedars, white, Port Orford, Alaska and Western red; also cypress, mahogany and its sister wood, Spanish cedar; white pine, which is largely used for dories, and Western spruce. Teak is sometimes used, and aside from its weight is of course splendid.
All planking should be practically clear, also vertical grain if possible, particularly for the top sides where also wide planks should be avoided (except for skiffs and similar construction).
Framing.—Oak and mahogany are most widely used, but where lightness is a large factor spruce and the harder cedars also, as well as close-grained Douglas fir. These softer woods may be used in any sawed frame boat, but larger fastenings should compensate for the poorer holding power. Material for sawed-frames need not be clear, as knots (if not too many) may be easily avoided and a much cheaper grade of lumber used. Use bending oaks for bent frames.
Transom.—Being wide, it has a tendency to warp, which is one objection to oak; nevertheless oak should be included with mahogany, teak, and Spanish cedar. Among the soft woods the harder cedars, spruce, and Douglas fir; these should be vertical grain if possible.
Gunwales.—Any of the planking woods will do, but as subject to hard usage, oak or mahogany are better.
Seam Battens, Bilge Stringers, and Seat Risers.—Same as planking, but to include oak and yellow pine.
Seats and Floor Boards.—Generally are of soft woods, as lightness and weather resistance are most required. The cedars, spruce, Douglas fir, cypress, and white and yellow pine are used though mahogany and Spanish cedar are ideal. The navy often uses ash thwarts or seats.
Decking.—If canvas covered is always tongue-and-groove or matched and of cedar or white pine. If it is to be caulked, mahogany, teak, and Spanish cedar are generally used. Caulked decking should not be wider than 2½" and tongue-and-groove for canvas deck 3".
Deck Beams.—Douglas fir and yellow pine are commonly used; also oak and mahogany. Spruce is often chosen for its light weight, but does not hold deck fastenings well.
Cabin Trunks.—Mahogany, Spanish cedar, and teak are probably the most satisfactory if the trunk is to be varnished, in which case the whole exterior trim should be to match; any of the cedars are very good if to be painted.
Guards.—Oak, mahogany, bagac, and sometimes teak or almost any hardwood.
Masts and Spars.—Spruce is said to be the strongest wood for its weight in the Western Hemisphere and is almost universally used. Douglas fir, though excellent, is heavier.
Breast Hooks and Knees.—Oak, mahogany, or almost any hardwood.
Plywood.—Something should be said about plywood and the several patented composition boards. They are ideal for bulkheads, web frames, and stiffeners, and several stock-boat manufacturers are using them for planking in certain types of boats. The plywood must be put together with waterproof glue, otherwise it is absolutely useless. It should be well painted, especially the edges. Make sure that any of the above materials are guaranteed for the purpose by the manufacturer.
The Lumber Order
Most of the cedars and also the hardwoods are stocked in the rough and surfaced to order. Generally one quarter of an inch is allowed for surfacing two sides, but this depends on how closely the lumber has been sawed. It is sometimes possible to get 15/16" boards from 1" stock and it should not be necessary to lose more than 1/8" in the surfacing process. By this I mean that a 7/8" board surfaced on both sides should be obtained from 1" stock.
Douglas fir and several of the pines may be purchased and, in fact, are most frequently sold surfaced four sides or S. 4 S. Following are the standard Douglas fir or Oregon pine sizes and the rough stock they are each made from.
In ordering a 2 × 6 from the above you will, for example, receive a piece 1 5/8" × 5 5/8" unless you order net sizes, in which case you will get the exact size ordered. It is always cheaper to use stock materials, and the above sizes should be kept in mind when making out the lumber order. When ordering, include something for crossbands and other odds and ends used in setting up the boat.
Some explanation should be made of the lumber orders accompanying each of the plans in this book. The thickness is always net, but the width may be either net or the surfaced dimensions unless followed by the letter N. For example, if the order calls for one Pc. ¾" × 10", either ¾" x 9½" or ¾" × 10" will do. In case you can obtain planking or framing lumber S. 2 S. or S. 4 S. always choose the former as even this slight extra width may be useful. Following are some symbols used by the lumberman. S. 2 S. means surfaced two sides, S. 1 S. 1 E. is surfaced one side and one edge and so on, N. means net or exact size ordered, V. G. means vertical grain, B. M. means board measure.
Air-seasoned lumber is in every way superior to kilndried; particularly is this true of planking. With a little forethought the builder can often season the planking himself. Quite a bit of time usually elapses before he is ready to use it, and if piled with slats between or stuck and placed where air will circulate through the pile, it will soon dry out.
For boatbuilding purposes all fastenings must be either galvanized or of some corrosion-resisting metal, such as copper, brass, or bronze.
Nails are generally galvanized unless they are to be clinched or riveted, in which case they are copper. The square, cut, or boat nail is used for plank fastenings (see "Plank Fastenings"). The round or wire nail is used elsewhere about the boat and its rough, galvanized surface adds greatly to its holding power. In the dory lap, seam battens, or wherever a clinched fastening is required, the copper cut or boat nail is used. They should be driven against a hold-on as in Fig. 18, and not bent over after driving. Wire nails are ordered by "penny," boat nails by length, and the first table on page 4 shows lengths per "penny" and approximate number of nails to the pound.
Brass or composition screws are superior to the galvanized in that the threads are much sharper and clear cut. The screw must be galvanized after the thread is cut, and the zinc coating tends to fill in between the threads and destroys the clear-cut edges. Brass or bronze screws for this reason are always used for the smaller sizes, but from a number ten screw up the galvanized one does very well. The following is a useful table of screw sizes. The size of head is given as occasionally when the head is to be counterbored for and plugged, this dimension is of importance. The head is roughly twice the shank diameter.
Carriage bolts have largely replaced the old clinch bolt, and may be purchased in diameters from 3/16" up and in almost any length. If possible, purchase the cut thread and not the pressed thread bolt. As in screw sizes it is often desirous to know the diameter of the head, this is given in the following:
[ILLUSTRATION OMITTED]CHAPTER 3
Lofting or "Laying Down"
THIS CONSISTS IN enlarging to full size on the mould loft floor the lines of the boat. These consist of three views of the hull lines (see Fig. No. 1); one viewed from above is called the "half breadth," showing the shape of deck, and of horizontal sections through the hull, called water lines and abbreviated W. L. on the plans. In the lines of a round-bottom boat the diagonals would also be shown, but we are not concerned with them here. This plan is generally at the bottom. Above it is the profile or side view of the boat, showing height of deck or top of sheer strake, rabbet, keel bottom, etc., and often some vertical fore-and-aft sections called "buttocks." The last or body plan is a view from each end of the boat, showing vertical cross-sections of the hull, and as both sides are alike the shape of the forward end is shown one side and the aft end on the other side of a common centreline. In all the above plans the bow is shown to the right. The different lines drawings as designated above are also labelled in plans of Tern, an 18' runabout. Often the body plan is superimposed over the profile, as in many of the plans shown here.
I have endeavored to make it possible, with few exceptions, to construct each boat by laying out the body plan only (see Fig. No. 6), the keel, stem, etc., being shown in separate detail. There is something to be gained, however, in completely lofting almost any boat. A slight unfairness in a scale drawing is greatly magnified when enlarged to full size; these discrepancies can be eliminated in the mould loft and at the same time the amateur will gain valuable experience in the operation. There is no advantage in laying down the simple skills or punts, and the builder can follow his own inclination as to the others.
A clean, unpainted or freshly painted surface is the best loft floor, but light-colored building paper will do and has a certain advantage in that the lines may be stowed away for future use. Referring to Fig. No. 1, the first thing is the base line, then the centreline parallel to it, and the frame stations 1, 2, 3, etc., square off base and centreline. The boatbuilder makes one line do for horizontal centre, and base line, and superimposes the three lines drawings one over the other. You can do this if you wish, but try to keep the body plan separate. If possible, and it is not too large, put it on a sort of enlarged drawing board; you can then lift this on to the bench or some horses and assemble your frames there. For clarity, the frame outlines in Fig. No. 1 are shown at their respective stations instead of being all assembled in a body plan, as in Fig. No. 5, and the station line is in each case used as the vertical centreline. The waterlines are now drawn in on the profile and body plan, and the buttocks on the half-breadth and body plan all are straight lines so far.
All straight lines, including a body-plan centreline, being laid out, we may turn our attention to the offsets. These are applied first to the body plan and each frame is taken separately, the dimensions or offsets applied, and the frame drawn in lightly. To make this clear the offsets of Station No. 3 have been taken as an example. Refer from the offsets to the half-breadth and profile plans and you will see how each is applied (Fig. No. 1; also see Fig. No. 6). If you are laying out the body plan only, this plan (Figs. Nos. 5 and 6) will finish the operation of lofting, and any reference above to profile and half-breadth will be disregarded. The plank thickness must yet be taken off, however, at each frame.
It may seem strange that offsets are not given to inside of planking or actual frame shape instead of to outside of hull. This, however, is standard practice with all naval architects and boatbuilders and for practical reasons. Displacement and all calculations are made to the outside of plank and plank thickness can be deducted with greater accuracy in the mould loft than on small lines drawings; also the rabbet and bearding line would complicate offsets if to inside of plank. On small boats the thickness is simply deducted on the body plan and a new line drawn representing the actual frame, not, however, until the operation of lofting is completed.
Turning now to the fore-and-aft lines, the stem profile is laid out from the dimensions given (or by scaling the plan) and connected with keel bottom. From this point all lines are now obtained from the body plan in the process of fairing up. This consists of taking the half-breadths and heights from the body plan and transferring them to their separate stations on the half-breadth and profile. Take each line separately; for instance, take all the sheer heights and mark them on their respective stations and spring a batten through these spots. Fig. No. 1 shows how the endings of these lines at stem are obtained for the half-breadth plan by squaring them down from stem face on the profile. The sheer height and chine must be run in the profile before these lines can be ended in the half-breadth, and the process is reversed for the buttocks if shown, and if they intersect with chine this is squared up to chine in profile. A thin batten about the size of a yardstick is used in transferring all marks, which are transferred from body plan to stick and thence to the other plans much easier than could be done with a rule. Most of the above may be made clear by a study of Fig. No. 1 much better than it can be explained.
Excerpted from How to Build Wooden Boats by Edwin Monk. Copyright © 1992 Dover Publications, Inc.. Excerpted by permission of Dover Publications, Inc..
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