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Boatbuilding Manual 5th Edition

By Robert M. Steward, Carl Cramer

The McGraw-Hill Companies, Inc.

Copyright ©2011 International Marine/The McGraw-Hill Companies
All rights reserved.
ISBN: 978-0-07-162834-1

Contents

PREFACE TO THE FIFTH EDITIONFOREWORD TO THE SECOND EDITIONPREFACE TO THE SECOND EDITIONPREFACE TO THE FIRST EDITION1 GENERAL2 PLANS3 TOOLS4 WOODS5 FIBERGLASS AND OTHER HULL MATERIALS6 FASTENINGS7 LINES AND LAYING DOWN8 MOLDS, TEMPLATES, AND THE BACKBONE9 SETTING UP10 FRAMING11 PLANKING12 DECK FRAMING13 DECKING14 DECK JOINERWORK15 INTERIOR JOINERWORK16 FINISHING17 SAILBOAT MISCELLANY18 STEERING19 TANKS, PLUMBING, ETC.20 MECHANICAL AND ELECTRICAL21 POTPOURRI22 SAFETYAPPENDICESINDEX

Excerpt

CHAPTER 1

GENERAL

DURING THE PAST SEVERAL DECADES, more and more people have learned how toskillfully use both hand and power tools for household chores and improvements,making furniture, outbuildings, and the like, and they often turn out verycreditable jobs. Such people are good candidates for boatbuilding. Yet many areintimidated by the thought of making something that is not all square corners;bending wood or other flat material to form curved shapes discourages them. Andwhen they look into boatbuilding and see that it usually starts with a linesplan and the attendant table of offsets that dimensions the curves—well,that’s that. But these people are unnecessarily depriving themselves ofa very fascinating and satisfying pastime. It is true that many types of craftdo require coping with the basics of traditional boatbuilding, but this can belearned to the necessary degree, and studying this book is a good start.

On the other hand, many people are happy with the kinds of boats that can bebuilt using waterproof marine plywood. Some of these are virtually frameless.But more about this when you dig into the following chapters.

Constructing the first boat, however small, is an unforgettable experience.Watching a hull grow from flat paper drawings and flat material into a shapelyform provides hours of fun and is excellent therapy after a stressful day. Whenthe job is done carefully, the finished vessel is a source of great pride to thebuilder. And unlike a piece of furniture, which is often put in a corner andsoon forgotten, a boat is used over and over for pleasure through the years.

A number of lucky people with the desire to learn boatbuilding have been able totake courses in various parts of the united States and the world. Currently,there are a number of good schools for boatbuilding in almost every country. Butthere will always be legions of aspiring boatbuilders who lack the money, thescheduling flexibility, or the proximity to attend one of these schools, whichmeans there will always be ample reason for books like this one.

The purpose of this book is to introduce boat Construction by explaining theelementary problems involved from starting the hull until water first laps atthe keel. I don’t purport to teach all the skills of an expert boatbuilder.

It is impossible to cover briefly all the information needed to build every typeof boat, especially in view of new methods being developed. If you are fortunateenough to live in a boatbuilding area, you can learn a great deal fromobservation. When it comes down to building the kind of boat you want, youshould bear in mind that a good set of plans is not only insurance againstdisappointment, but is also a source of Construction details. In this book, Iassume that you have acquired the ability to use ordinary carpentrytools—not much more is needed to build some boats—and, of equalimportance, that you know how to keep your tools sharp. Nothing is worse or morediscouraging than trying to make progress by hacking away with dull tools; thereis no excuse for doing so. If you are a victim of dull edges, better take a weekoff in order to learn how to sharpen tools. A great reference is SharpeningBasics, written by Patrick spielman. Another is Fine Woodworking onPlanes and Chisels. You’ll find complete publishing information on these andother books in the Appendix.

Along with the many modern products imported from Japan has come an increasingnumber of hand tools that are anything but modern, and made with steel thatreally sharpens well. In one mail-order catalog there is a story, told by anAmerican tool buyer, of a Japanese woodworking shop in which the apprentices donothing but sharpen tools for six months. So don’t fret when you have to spend afew minutes bringing the edge of a chisel up to grade. Incidentally, I canattest to the effectiveness of Japanese water stones for honing, but to each hisown.

The main thrust of this book is toward wooden Construction, but the basics alsoapply to the layout and building of molds and templates for non-wooden hulls andto the finishing off of boats with non-wooden hulls.

If the project is to build a boat of a material other than wood or fiberglass,then another field has always been open, namely the cutting, shaping, andwelding of metal. Builders of metal boats utilize many of the basic woodboatbuilding techniques, but for book-learning about metal hull Construction,refer to the Appendix.

A person considering the building of a boat very likely has been exposed toboats and boating, either for pleasure or for commercial purposes, and may havea pretty good idea of what he/she wants—sail, sail and power, oars orpaddles, or pure power. Yet I have received mail about boatbuilding over theyears from people with no boating experience and nothing more to go on than ahope of being waterborne in the future. Somewhere along the line they mustchoose a certain type of hull after deciding what their requirements are.

There are three basic hull types: flat-bottomed, v-bottomed, and round-bottomed.Sawn in two at mid-length, sections through these hulls appear as shown inFigure 1-1.

The flat-bottomed hull in cross section consists of straight lines runningacross from side to side. The bottom may also be a straight line when viewedfrom the side (such as in a scow or barge), or the profile of the bottom may becurved, or “rockered.” In any event, the flat-bottomed hull is the easiest tobuild, has a minimum of beveled or twisted parts, and, if properly designed, canbe a useful craft. Flat-bottomed skiffs are found the world over; flat-bottomeddories have a long heritage. Then there are pram dinghies, garveys, etc., whichall have their places. In general, though, boats with flat bottoms are best usedon sheltered waters. A lines drawing for a flat-bottomed skiff is shown inFigure 7-4 (page 145).

The arc-bottomed boat is a variation of the flat bottom and a close cousin tothe v-bottom. Probably the best known arc-bottomed design is the Star classsloop. These 22-footers are still sailed worldwide, though they were designed in1911. Both the flat and the arc-bottomed hulls require the minimum of layoutwork prior to building, as will be seen later.

The frames for a v-bottomed boat are made from a full-size drawing of the hullsections and then set up and left in the hull as permanent members of thestructure. While this involves less work and less money for materials thanframing a round-bottomed hull, it still calls for careful fitting. The chinepieces (corners in the sections of a v-bottomed hull) must be carefully workedto achieve bevels that continually change from bow to stern. The frames, too,are all beveled, and each is made up of as many as seven carefully fitted andsecurely fastened parts.

A round-bottomed hull has curved transverse frames that are sometimes calledribs. These are shaped by steaming or soaking them in boiling water until theyare supple enough to be bent either directly on the hull framework or over formsin the shop, and then located in the hull after they have cooled and set. Mostboats of the size a beginner would build have frames bent right in the hull; thebevel necessary to have them conform to the hull shape is twisted in during thebending process. Do not let this scare you. When working with relatively lightmaterial, the bending is not unduly difficult and can be mastered after a fewattempts. In fact it can be a great deal of fun. The process will be describedin more detail further along, during a discussion of framing.

An alternative to bending frames of one piece is laminating them of glued stripsthin enough to take the necessary bend without treatment.

Bending wood by steaming or boiling is not restricted to round-bottomedConstruction alone, as it is entirely possible that certain parts of v-bottomedboats, such as the forward ends of bottom planks, will not bend on the boat coldand must be made limber for them to fit the shape of the hull.

Figure 1-2 is a lines drawing for a small round-bottomed hull. Linesdrawings are discussed in detail in the chapter on lofting, which is the makingof full-size hull drawings and templates for the various parts.

The relative merits of the hull types are argued far and wide, but just abouteveryone will admit that there will never be a v-bottomed hull as handsome as awell-designed round-bottomed boat, especially for a sailing craft. I am probablyprejudiced, so argue away!

Figures 1-3 and 1-4 show the essential differences between theframing of flat-, v-, arc-, and round-bottomed hulls. Although the lower ends ofthe frames in the round-bottomed boat are shown butted against the keel, it issometimes possible, depending on the hull shape, to install them in one piece,extending from the deck on one side to the deck on the other side. In contrast,note the number of pieces that make up a frame for a v-bottomed boat. On theother hand, frames are spaced farther apart than in a round-bottomed boat, sothe frames are fewer in number.

Figure 1-5 is a section through a rather normal sailboat of the cruisingor classic ocean racing type. The Construction is typical of either the so-calleddeep-keel or combination keel-and-centerboard type boats, the latterbeing of moderately shallow draft, greater than an unballasted centerboarder butless than the deep-keel type. This type of boat is not recommended for theamateur’s first attempt at boatbuilding unless he/she has helped on a similarjob or has watched enough of this kind of Construction that he will not becomediscouraged when on his own. The framing is more difficult due to reverse (S)curves in many of the frames, the planking is a tougher job than on a simplerhull, and there is a lot of heavy work getting out the backbone and deadwood.

The time needed to build a hull can be reduced if the hull shape is such that itcan be covered with large pieces of flat material such as plywood. If a hullshape does not have compound curvature it is called “developable” and can beformed from flat sheets. There are ways of designing a hull with developablesurfaces, either graphically on the drawing board or with a computer program.The surfaces are cylindrical, conical, or a combination of both, and thedesigner must be content with the limitations of these curves, but there are agood number of choices. More about this in Chapter 7.

Figure 1-6 shows the lines for a 52-foot hull that was designed with the aidof a computer. This boat was built of large fiberglass sheets: one for eachside, one for each half of the bottom, one for the transom, and a number ofjoined strips for the wide chine surface on each side. To my knowledge, this wasan unusual method of Construction at the time (1969). On the other hand, the v-bottomedhull in Figure 1-7 cannot be built in this manner, for thereare concave sections in both the sides and the bottom. Flat sheets cannotsuccessfully be bent in two directions at the same time.

Most of the figures in this chapter have been labeled with the names of some ofthe principal hull lines, and the beginner must become familiar with thisnomenclature. For instance, the top edge of the hull viewed in profile is thesheerline, while the same line viewed in plan is the deck line, or deck at side.A chine is obviously the intersection between the side and bottom of a v-bottomed hull. Other lines in the surface of a hull will be explained later.Since both sides of a boat are usually the same, a designer draws the lines foronly one side of a hull.

For hundreds of years, wood was the primary material used for building hulls,but matters are different now. As this is written, boats of fiber-reinforcedplastic have been manufactured for more than 50 years; fiberglass boats dominatethe standardized boat market, with hulls and other parts produced in volume fromexpensive molds and tooling.

But research never stops; resins have been improved, and there is a largerchoice of reinforcements, some of them currently expensive but enormouslystrong. As of 2010, skilled amateurs as well as professional builders arebuilding fast, strong racing boats from foam and carbon fiber, but thistechnology is not yet sufficiently well-established or user-friendly to becovered in this book. Look for that to change in the future.

Nor is wood dead. Both pleasure and commercial boats are still built of wood.Wood is being used in hulls in the conventional manner, some are built withplywood planking, and other hulls are made with multiple layers of relativelythin wood glued together and then often covered with a resin reinforced with asynthetic fabric.

The techniques of wooden boatbuilding are extensively employed in theConstruction of tooling for fiberglass boats and parts. Wood is used for theinterior joinerwork in the better-quality fiberglass boats to avoid the cold,antiseptic appearance of the molded plastic and “mica” finishes that have becomea logical extension of molded fiberglass hulls and cabins.

When demand is limited, such as for yachts 65 feet and longer, cold-moldedcomposite (wood and epoxy) Construction has become increasingly popular. True,welded aluminum alloy Construction or a welded steel hull with superstructurebuilt of the light alloy is still the choice of many of the larger builders. Buthere again, wood is usually chosen for the finish in the quarters because itprovides a feeling of warmth that can never be achieved by the synthetics.

It is possible to gain an introduction to boatbuilding by purchasing andassembling a “kit” boat. There are a number of kits for v-bottomed motorboats,sailboats, canoes, and kayaks, usually with plywood planking. And there has beena proliferation of kayaks and canoes from a number of vendors. Most of thesekits are furnished with beveled parts that require only reasonable care to setup the frames accurately to form the hull. Then there are firms that supply abare fiberglass hull as part of a kit. Here is where an amateur must be carefulto be sure that guidance is provided or available to locate components such asengines and fuel and water tanks. The weights of such items can be quite large,and the amateur should not bite off more than he/she can chew.

Making a kit boat does not give the same sense of accomplishment as building aboat from scratch, but the scheme does make sense for those with limited sparetime or for those who want a particular model of boat that is available in kitform. And building a kit is a great introduction for the first-time boatbuilder.Shown here are photos of some of the many types of boats that can be built fromkits (see Appendix). Except as noted, all these boats were constructed entirelyfrom kits by amateur builders.

CHAPTER 2

PLANS

THERE ARE SEVERAL WAYS TO GO once you have decided to build a boat. You canbuild from scratch using plans from one of the many sources available nowadays,buy a boat kit, or buy full-size paper patterns for hull parts. Refer to acurrent boating magazine or use online search for plans.

The boat of your dreams may be a simple rowboat, a boat for both rowing andsailing, a daysailer or cruiser, a power craft for waterskiing or fishing orboth; or you may set your sights higher, and be satisfied only by a largerpowerboat for cruising. Whatever the type and size, take your time selectingplans. Remember, it takes only a second to decide to build your own boat, but itmight take years to complete it.

There is a wealth of plans for plywood composite Construction methods such asthe stitch-and-tape method, sometimes called stitch-and-glue or taped-seam. Thismethod is discussed in Chapter 11. Some designers offer full-sizepatterns for the hull parts to be made from flat sheets; others furnishthoroughly dimensioned scale drawings for the parts.

Lofting, discussed at length in Chapter 7, is the process of drawinghull lines full size, working from the designer’s scale drawing. Much, if notall, of this work is eliminated when building a hull by the stitch-and-tapemethod, but such hulls are limited to the shapes that can be formed from flatpanels.

There are also designs available for a number of other Construction techniquesincluding lapstrake plywood, strip Construction, and traditional woodenConstruction, as well as for other methods and materials covered by this book.

Regardless of their source, try to determine whether the plans that interest youare sufficiently detailed for you to completely understand the vessel’sConstruction. It cannot be emphasized too strongly that good plans are wellworth their price, because their cost is but a fraction of the total cost of theboat. The cost of the plans might be considered as insurance that the finishedboat will be a success. When designers do not draw the profusion of details thatthe novice builder would like to have, this book should be very helpful infilling in some of the missing information.

I would warn you against making changes in the hull lines, heights ofsuperstructures, or locations of major weights. Such procedures can result inunsatisfactory performance at the least, or even downright reduction ofseaworthiness. Consult the designer before making any major changes, and if headvises against them, you will be better off using plans that will give you whatyou want without departing from the drawings.

EXAMPLES OF PLANS

I am using plans I drew over the years as examples of adequately detaileddrawings. The Rudder magazine, which unfortunately disappeared manyyears ago, was once known far and wide for its down-to-earth practical contentand “how-to-build” small craft plans. I was fortunate enough to be selected todo a number of these. In fact, in 1950 The Rudder collected a series ofmy monthly boatbuilding articles and published them as Small BoatConstruction, which was actually the first edition of this book. Themajority of the illustrations from that first edition, drawn in 1949–1950,still appear in the edition of Boatbuilding Manual 5th Edition you are reading now.When it comes to building wooden boats, the old expression really is true: Themore things change, the more they stay the same.

Figures 2-2, 2-3, and 2-4 are plans for a 19-foot arc-bottomdaysailer I did in 1948 for The Rudder to the general specifications ofthe magazine’s editor. I named this boat “Triton” (a name I do not think hadbeen used for a class of boats at that time). Over the years I have heard goodthings about the design from as far away as England (where the builder obtainedthe framing lumber from an obsolete British army truck), Brazil, and Cuba, justprior to the Castro revolution.

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