been made available for engineering applications and the hardware is minimized if the first or but are not all described in detail in this article. minimal non-zero coefficient irreducible poly­ The format of the burst correction tables facilitates nomial in Marsh's or Peterson's tables is used. the selection of a particular code or the evaluation A special-purpose computer has been developed of several codes in that codes are listed in increasing at the Applied Physics Laboratory to perform order of burst correction capability, increasing multiplication and division of polynomials in the order of the irreducible polynomial exponent, and binary number system and in the required algebra increasing magnitude of the check symbols. The when it is desirable to use a shortened code, thus capabilities of very long codes are retained or even eliminating the need for hand computation of increased after shortening the codes to mechanize residues. The same device doubles as an encoder them. This property should be noted. A simple or decoder simulator for generator polynomials mechanization is available if shift registers are used of degree 36 and less.

Ways and J. R. Apel Means of

The two most beautiful forms in To those who know and under­ the emphasis on speed boats and creation belong to a well-designed stand them, there is real beauty in hydroplanes; and an examination, in sailboat and a well-shaped woman. the lines of a or the set of the a bit of detail, will be maeole of a A categorical statement such as this rigging of a boat, be it an 8-foot 150-mph Gold Cup h ydroplane. The would ordinarily bring a flood of dinghy or an 80-foot diesel yacht. presentation of this article will be abuse upon the person who made it, To those who are untrained in things given from the standpoint of one but among judges of boats and nautical but who respond keenly whose vocation (in more fortunate women, the statement goes virtually to the visual arts, it is apparent that times, perhaps) encompassed much uncontested. Though both subjects ships and boats have a high degree of this subject matter, but who is would make an interesting discussion, of functional styling about them. It now reduced to boating and boat this paper will concern itself only takes only a bit of study and ob­ design as an avocation only. So this with boats. servation by the novice to become will be a "hobby" article. educated to some of the niceties of Few of the technicalities of the the business and to become convinced trade will be presented and virtually J. R . Apel, a physiqst in the Plasma that the old saw about boats being no connection will be made with its Dynamics Group, co-authored a paper called "she" has more truth to it mother-science, . This entitled " Beam-Plasma Interactions" than would appear at first glance. is because first, the technicalities are in the May-June 1964 Diges t. Com­ This article will discuss the de­ not too interesting and second, yacht ing from a boatbuilding family, Mr. sign of pleasure boats and the de­ design is much more nearly an art Apel studied boat design at the signers; it will also discuss the con­ than a science. With the exception vVestlawn School of Yacht Design siderations that enter· into designing of a few craft such as the 12-meter and practic.ed this profession for different types of boats. Examples racing sailboats of recent years, several years. of a few designs will be shown with orderly research effort in pleasure

18 APL Technical Digest boat design (such as aircraft are sub­ boats. They may calculate their load jected to) has not been great. waterline on the hull using Simp­ son's rule (but not know integral calculus from vichyssoise) or they Naval Architecture may take the experimental approach The fundamental problem in naval and paint the waterline on the fin­ architecture is to design a boat or ished boat only after floating it in ship that is seaworthy, safe, and grimy water and letting the line de­ speedy, and that serves some spe­ fine itself in dirt on the hull. Either cialized purpose-cargo carrying, fish­ way is workable and, for boats the ing, racing and so forth. The success size of many pleasure craft, entails with which the problem is solved for comparable amounts of effort and small craft is chiefly a function of expense. One might not trust the the skill and experience of the archi­ practitioner of the second method tect, since the analytical rules of the with any design more complex than game are few and flexible. One re­ a coal barge, but he will make a liv­ sult of this lack of hard criteria is ing nevertheless. that the small boat designer is usu­ ally trained less formally and more Four Pleasure Boats practically than his colleague who designs ships. If properly under­ As an example of the end products taken, the practical training is often of a designer's efforts, four distinct as good or better for the purposes types of pleasure boats are discussed at hand, again because of the large in the following paragraphs. They empirical factor involved. are graduated according to hull type, However, anyone, trained or not, starting with a pure displacement can produce a workable boat. In fact, hull wherein virtually all the lifting with no other type of vehicle does force derives from Archimedes' an­ one find so many nonprofessionals cient law, and ending with a racing audacious enough to design and hydroplane that planes on the sur­ build their own platform and cour­ face and is nearly airborne at top ageous enough to set foot in the speed. thing when it is done. Witness the native with his log dugout canoe, the A Sailboat coastal fisherman with his ungainly Fig. I-Model of a 43-foot sloop designed but stout 50-foot vessel built without Let us return to the statement at for racing in shoal waters. Note the long, benefit of a single blueprint, and the beginning of this article. What graceful lines of the hull and the height of the . the basement builder struggling to is it that makes the sailboat hull such loft, or layout full size, the lines of an object of beauty? It is functional­ his 16-foot outboard from plans ism , a design perfectly attuned to the sail under 45° heel, perhaps, with a bought for $5.00 from the hobby element in which it must live. In large reserve righting moment re­ magazine. These people are some­ a sailboat, the requirement of har­ maining for safety's sake. Its masts times indecently successful. Witness mony has ideally resulted in an and rigging must take the strain of a also the degree of refinement ex­ object of sweeping, graceful lines that spread of canvas whose area amounts hibited by Messrs. Sparkman and cases the water around it with min­ to several times the lateral area of Stevens in the design and testing of imal effort, that reacts to heavy seas the hull supporting them. It must their exquisite series of 12-meter with rapidly increasing buoyancy as remain watertight, buoyant, and America's Cup defenders, or the engi­ it plunges in, and that sails almost amenable to control under these con­ neering and skill displayed by an air­ as well halfway over on its side as it ditions and preserve some degree of craft designer, Ted Jones, in concoct­ does upright. In many respects, the creature comfort at the same time. ing the first 200-mph hydroplane, problems facing the sailboat designer H is easy, for example, to design Slo-Mo-Shun IV. These latter are in providing for these ideals are ample righting moment into a boat professionals, of course, and special­ more complex than in any other and make her almost impossible to ized ones at that. Amateurs embark­ marine design task. His product must capsize; without care, however, the re­ ing on this level of activity are likely make efficient use of wind with a sultant response will be so quick that to meet with disaster. speed varying from dead calm to under the influence of a rolling sea For the most part, the boats one greater than whole gale and whose she will pitch crew and crockery sees in the magazines are direction will range from some 30 to athwartships with such force that the designed by people who have learned 40° off the bow to dead astern, using a breakage factor for both will be in­ their trade by observing boats, build­ sail that acts much like a very limber tolerable. That all these require­ ing boats, running boats, and loving . It will be required to ments are not always met is obvious

November-December 1965 19 enough and the result is sometimes A Power Cruiser the typical cruiser will serve as fish­ less than pleasant for boat and crew. ing boat, a 2-week vacation retreat, During the long evolution of sail­ Proceeding on from sailboats, the a floating cocktail lounge, and an im­ ing vessels, the shapes of hulls and next hull type on our list is the semi­ portant part of the customer-rela­ rigs have been developed to displacement power cruiser, probably tions department of the owner's busi­ a high state of refinement and they the most familiar species of pleasure ness. She does all these things well. are still evolving. There is a con­ boat. This hull partially lifts itself In addition, she must be a seagoer, sensus that the general type of ar­ out of the water as its speed increases for ocean sport fishing beckons. The rangement exhibited by the sailing hut in the main remains buoyed kind of vehicle that results may look sloop of Fig. 1 is one of the m ost statically rather than supported dy­ much like the yacht shown in Fig. 2. efficient devised to date for smaller namically. This is a highly seaworthy, 35-foot seagoing boats, say less than 65 feet It is here that the feminine in­ round-bottom Jersey that the overall. The illustration shows a fluence on yacht design has made author has skippered, built for break­ model of a 43-foot fast racing sloop itself felt most strongly, for while a ing the rough shoal inlets found designed by the author, but never sailboat is pretty much what her along the Eastern seaboard. Her built (fortunately, perhaps, since sail­ environment demands she be, the cabin lines are somewhat severe and boat design is not his forte). She is power cruiser in the last few years her grace is not increased by the rather keen, her beam being only has become more what the skipper's fl ying bridge used for control while 8-1/2 feet, and of somewhat shallow wife demands it be, at least from the sports fishing. This type of boat tends to have a narrow , and the has a fair amount of rocker, or f9re-and-aft curvature, to allow the seas to slip under her. They are usually clinker-built, with one plank overlapping another, but this one is smooth-planked. She is extremely able as cruisers go; twin l25-hp en­ gines make her very maneuverable and permit a normal operating speed of about 12 knots. Sleeping accom­ modations are for six and she is equipped for extended cruising. She was designed and built by Van Sant in Atlantic City, where she summers; winters are spent in Florida in the company of her better-looking sisters built by Chris-Craft, Owens, or the like. Fig. 2-A 35-foot Jersey sea skiff, Cap's Baby. This cruising boat is comfortable and All in all, the design of a power stable, though not as highly styled as some. cruiser is a much simpler under­ taking than is the design of a sail­ draft for a boat of her size-5 feet. standpoint of styling and cabin ap­ boat of similar size, and the conse­ Her large Marconi-rigged mainsail pointments. Fortunately, hulls suffer quences of mistakes are not so drastic. and jib present about 900 square feet little in this process- although there of area to the wind and are counter­ is the story about the yacht designer An Outboard Speedboat balanced by some 8500 pounds of who gave his wife free rein in the lead on her keel. The hull cross­ interior arrangement of his personal My own speciality has been the sections are of the typical wine-glass high-speed planing cruiser. Such design of speedboats and hydro­ shape. She is designed for racing hulls are very sensitive to weight­ planes. These terms are used in the in rather shoal waters like the Chesa­ and the inclusion of items like plate generic sense since a hydroplane is peake Bay; as such, she is rather glass mirrors in the owner's quarters a speedboat, by necessity. "Speed­ specialized, in somewhat the same and an organ in the main salon boat" or "runabout" is usually re­ sense as an Indianapolis racing car proved more than the good boat served for the nautical equivalent is specialized. Although beautifully could bear. She failed to plane be­ of a sports car; that is, a peppy, open shaped, the boat would probably not cause of the extra weight and it cost boat that planes on top of the be too comfortable for long cruises the designer the price of two larger water, is capable of speeds between 25 since her fine lines do not yield the engines and a major reworking of and 45 mph, is safe for skimming interior space or easy motion that the hull to correct it. around in protected waters, skiing, cruising comfort demands. On the The important considerations in a fishing, and general waterborne ran­ whole, it is a boat for a racing owner cruiser are seaworthiness, comfort, dom motion. and not general purpose usage. and maneuverability. In normal use, With the advent of high-power,

20 APL Technical Digest reliable outboard engines, the small free of bumps and hollows and are drag, of course. If improperly de­ outboard speedboat has come into self-consistent from one view in the signed, the hull does not . effi­ its own. It has been an appreciable drawing to the other. ciently; a large wave is generated factor in making pleasure boating the There are good reasons for the astern from the downward velocity over-two-billion-dollars-a-year busi­ hull shape shown in the drawing. imparted to the water and a for­ ness it has become in recent years. For example, the large amount of vee ward "" occurs under the hull It is a boat that even families of bottom up forward acts as a wedge where it first contacts the surface. modest income can aspire to and it that enters the water and cushions All this costs in power. A more can be trailed behind the car to a the shock of traversing waves at high proper design minimizes these effects; variety of watering places, thus cir­ speed. Also, vee in the aft sections its propriety will become apparent cumventing dockage fees and adding causes the boat to bank in a turn, from the small wake left in the water variety to the owner's boating vistas. thus providing a centripetal force and the increased boat speed. A boat An example of the hull design of a and improved turning. However, a having the weight and surface area runabout is shown in Fig. 3. This is flat bottom is the most desirable of the boat in Fig. 3 should plane a set of line drawings arranged in configuration for efficient planing at speeds above 25 mph. the traditional fashion of naval and hence the bottom lines must The remaining hull characteristics architects, and shows the top and transform from vee forward to flat are chiefly determined by considera-

CHIN E LWL BUTTOCK D

BUTTOCK C

BUTTOCK B

BUTTOCK A

~~==±=====~=====±======~====±=====~====~==~~~~~---- ~

SH EER DEC K ~ \; y /' / / / 1 WL IV; \ 10 ~ V7 WL III ; - '--- ~ // 12 D 14 Vc Vs V ST EM WL \ -- ~ 16 RABB ET T K ~E L CHINE ~ ~ L ~/ LWL \ \ ~ ~-l----" BASELINE 16 14 12 10

Fig. 3-A typical lines drawing showing a 171h-foot, wood runabout suitable for either outboard or inboard-outboard engines.

side views (plan and profile) plus aft where the boat actually planes on tions of seakeeping. Breadth, or transverse sections, of a 17-1 / 2-foot the water. This evolution is dis­ beam, is required for stability; free­ vee-bottom boat designed by the au­ played graphically by the buttock board or height above the water is thor for personal use. The welter of lines. In addition, the keel line has needed to keep water out of the boat; lines becomes clearer when we ex­ rocker, or curvature, so as to minim­ similarly, the flare to the sides in the amine them one-by-one. The sheer is ize the amount of nonlifting bottom forward sections is to provide for in­ the line where the side and deck sur­ in contact with the water, by elevat­ creased buoyancy as the boat plunges faces meet; the chine results from ing the forward part above the flow. into large waves, as well as to throw side and bottom intersections; the As with a wing, the hull's angle of spray away from its occupants. The rabbet is where the bottom and side attack is determined by a balance inward curvature of the sides at the planking terminate and butt into the between weight and the normal com­ after end is termed tumble-home, its stem and keel. The remaining lines ponent of dynamic pressure inte­ origin probably being the need for are waterlines, buttocks, and sections, grated over the area in contact with the captain of a large sailing vessel all of which result from intersections the water, at a given speed. Usually to have a clear view upwards from of various sets of orthogonal planes this angle turns out to be about the windows of his quarters at the with the hull. These lines are useful 3-1 / 2° as measured with respect to the stern of the ship. Tradition has re­ in fairin[! the hull, that is. in making straight buttock lines. The tangen­ tained it in small boats. sure the various complex ,curves are tial component of pressure leads- to All in all, the craft in Fig. 3 should

November - December 1965 21 Fig. 4-Model of the 1940 three-point suspension hydroplane My Sin. A Gold Cup class boat, she exceeded 100 mph. be a good-looking, dry, relatively to the smallest inboard with a 48- having 13 as a registry number. smooth-riding boat for family use, cubic-inch engine, up through the Figure 5 is a schematic view of a capable of some 28 to 30 mph with 266-cubic-inch displacement, loo-mph typical 28-foot Gold Cup boat of a 45-hp outboard. Her framework IS footers, to the imperious Allison­ 1960 vintage, capable of some ISO will be built of oak and sitka spruce, or Rolls-Royce-powered Gold Cup mph when powered by a 171O-cubic­ and planked with mahogany. The boats. The classes are usually built inch, 2000-hp Allison aircraft engine. bottom will be sheathed with fiber­ around a readily available engine The view is from the water level and glass cloth and resin. This construc­ type-expensive specific racing en­ shows the boat in planing position; tion, coupled with her size and gines being prohibited as beyond the the stern is ou t of the water by a power, will be enough to give some pocketbook of most owners. The good fraction of a foot, lifting sup­ comfort to her owner if he should be Gold Cup-Unlimited classes are the port being derived from the propel­ caught in the short, steep seas that most interesting of all and we shall ler, of which only one blade at a the wind raises in a shallow body of concentrate on them for the re­ time is su bmerged . The engine water. I consider her a happy com­ mainde'r of the article. turns the propeller near 9000 rpm promise between speed and sea­ Almost to a boat, the big machines through a step-up gear box whose worthiness and hope to demonstrate are three-point suspension hydro­ ratio varies from perhaps 2.8 to 3.2 this when she is completed next sum­ planes, which means they ride skim­ to one. The propeller pitch and mer, provided I can get her out of ming across the water on two for­ diameter are both about 24 inches, my basement. ward protruding surfaces called spon­ and the boat makes good a distance sons or stabilizers, and on their . of about 80 % of this per propeller This type of hull was invented in the revolution. Supercharging is used A Hydroplane earl y 1930 's and was used in the firs t on the engines; often the "straight­ At the opposite end of the spec­ boat to achieve a mile-a-minute way" boats-ones attempting speed trum from blue- water sailboats are speed. By 1940, the design had pro­ records on a straight course -burn racing hydroplanes. These craft are gressed to the state shown in Fig. 4; alcohol for increased power. It was more nearly aircraft than boats, and this photograph illustrates a model under these conditions that Slo-Mo­ if the American Power Boat Asso­ of the My Sin, later to become Guy Shun, a Seattle boat, exceeded 200 ciation rules did not require that Lombardo's Tempo VI. Only 24 feet mph average speed on Lake Wash­ they derive their thrust from action long, she was not designed for the ington in a two-way run over a upon the water, or prohibit movable horsepower installed in her after measured mile; it took several times control surfaces acting against the World War II and she flipped at 105 this distance to accelerate and de­ airflow, Gold Cup and Unlimited mph while racing in the Detroit celerate, 6f course. hydroplanes would surely be jet­ River, breaking Lombardo's arm in The characteristic roos tertail thrown powered low-flying by now. the process. The sponsons are prom­ by the propeller flies some 60 to These are class boats, each class inent in the photograph and carry 80 feet into the air as shown in being determined by engine and boat the identification "G-13." One famil­ Fig. 6, and this jet of water is size, among other things. They range iar with all the superstitions in rac­ often responsible for wetting down from tiny outboards with 9-foot'hulls ing might wonder at the wisdom of and drowning out any boat foolish

22 APL Technical Digest STEER ING WINDSHIELD COWLING

SURFACE OF W ATER

Fig. 5-Schematic of an Allison-powered, ISO-mph hydroplane in running position, as seen from the water level. Only the edges of the sponsons and one blade of the propeller are in the water when proceeding at this speed.

enough to follow in the wake of the monsters is a thrilling experience, negotiating the racecourse is partly a first within a few hundred feet. This especially because speed in a boat is matter of pointing it in the general last photograph shows the two-seat magnified by the action and the very direction and hoping. Over 100 mph, hydroplane Dee-Jay IV underway at closeness of the water and spray. They the driver is buffeted by hard, sharp about 125 mph in slightly choppy are steered from the stern cockpit, accelerations from wave impact and water. Light is clearly visible under the seat being located behind the reaction to the movement. the hull and often the boat is com­ engine and the twin 6-inch exhaust The boat is permeated by exhaust pletely out of the water. Her general pipes. At the beginning, the starter noise, gearbox scream, and high-fre­ configuration is quite similar to that is wound up, engaged, and the big quency vibration from the propeller. shown in Fig. 5 and her riding posi­ engine catches and bleats loudly. One .\t 150 mph, one's senses are nearly tion is about the same. She was one is set back in the seat from the ac­ saturated, the remaining contact with of several big racers that the author celeration, for there is no flywheel, externals being barely sufficient to assisted in designing, building, and no clutch, no gears to ease the jolt. warn that the course markers' have testing-in this case not an altogether Underway at 60 mph, the boat is flashed by and deceleration must satisfactory experience, since the boat riding well up on the water's surface begin, gently now, to avoid pitching never overcame her bad luck and and the wind brings tears unless stern-over-bow because the foot came troubles. That amount of bad luck goggles are used. At speeds between off the throttle too fast. i8 unusual, however, and she was 80 and 90 mph, the stern lifts free even an exception to the rule-of­ under the influence of the propeller, In competition, with several other thumb that it takes a new hydro­ the roostertail develops, and the boat similar rigs adding to the conges­ plane at least two racing seasons walks crab-like to starboard from the tion, and turns to negotiate and before she begins to appear on the torque at an alarming rate. One roostertails to avoid, the situation winner's list in the regatta circuit. realizes that steering the thing is becomes even more confused ; and it The initial ride in one of these only an approximate maneuver and is time for the designer to abandon driving to the race driver and to sit on the shore, palms sweating, hoping his man can extract from his boat all that had been put into it, and worrying lest the 20 pounds weight saved hy shaving the thickness of the main trusswork might cost a broken boat or worse yet, a broken driver. If she takes the heat, or better, the race, the inevitable pride of having created a winner is the reward; if not; more art work may be needed, and musings about bal­ Fig. 6--A Gold Cup hydroplane underway at 125 mph. Light may be seen under the ance, trim, power, and the like take hull. The propeller throws a roostertail 60 feet in the air and several hundred feet behind the boat. over.

November-December 1965 23