sports boat, build a sleek

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sports boat Build a sleek sports boat By ARTHUR MIKESELL Designed by William D. Jackson, this sports sled has 50 sq. ft. of open cockpit and a rugged inverted-V hull. It'll seat six for fishing, yet is great for water skiing 2440

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Page 1: Sports Boat, Build a Sleek

sports boat

Builda sleeksports boatBy ARTHUR MIKESELL

Designed by William D. Jackson, this sportssled has 50 sq. ft. of open cockpit and a

rugged inverted-V hull. It'll seat six forfishing, yet is great for water skiing

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Page 2: Sports Boat, Build a Sleek

• DON'T BE FOOLED by the sleek, racy lines. Inspite of its high-style appearance, this soft-rid-ing inverted-V is a rugged, do-anything sportsboat that's fine for fishing, sensational for skiingand roomy enough to hold all your scuba gearwith plenty of space to spare. And it can takeanything you're likely to dish out.

To build it, follow these general rules:• Frame with the best stock lumber locally

available. Douglas fir, Philippine mahogany, yel-low pine or even the better grades of hemlockwill suffice, so long as the wood is reasonablyfree of knots. Lumber dimensions denote stocksizes, i.e., a 1 x 4 actually measures 13/16 x 3-5/8"• Use annular-ring boat nails (Stronghold An-chorfast or similar) and waterproof glue to se-cure the 3/8-in. plywood planking to the frame.Galvanized nails and screws are suitable if you

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Filler pieces mounted on the keelson are decreasing-angle wedges which give an inverted-V configurationto this member. The trial-and-error shaping of thesepieces to receive planking is part of fairing

Start planking at the transom and work forward. Thetwo 1/2-in. plywood butt straps at the planking jointsmust be cut to fit between the framing members. Sealall of these joints with fiberglass tape

plan to use the boat only in fresh water, butsubstitute silicon bronze if it will receive salt-water exposure.• Where necessary, make full-size paper patternsby using the grid system to enlarge the plan draw-ings. Transfer these patterns to the lumber orplywood with a dressmaker's toothed wheel.(You can make a suitable substitute by salvaginga gear from a discarded alarm clock and mount-ing it on a nail between the legs of a woodenclothespin.) Cut slightly oversize to allow for thefinal fitting.• Countersink all exterior fastenings slightly andplug holes with wood putty.• Fiberglassing is a matter of personal taste, buton this particular hull it is strongly recommendedthat you seal the below-waterline seams withfiberglass tape.

The first step is to cut and assemble all frames,Fig. 7. Fasten the side members to the bottomcrosspieces with glue and 1-1/2-in. No. 8 flatheadscrews, 3 per joint. Use the same size screws tomount the inner transom framing on the 3/4-in.plywood transom, spacing them about 3 in. apart.(The outer transom beam isn't installed untilafter the frame is planked.) Secure the 2 x 4transom beam by driving 2-in. No. 10 screwsfrom outside the plywood. And remember tocoat all contacting surfaces with glue.

When you have finished frames 2, 3 and 4,brace them with 1 x 1 tie bars as shown to pre-vent distortion during the rest of the buildingprocess. Note that frame 2 is braced with 1 x 2doubling pieces on each side of the bottomcrosspiece. Mount these with glue and 1-1/2in.

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sports boat

No. 8 screws. Don't forget to notch the upperbeam in frame 1 to hold the foredeck battens.

While the glue in the frames is hardening,turn your attention to the longitudinal framingpieces, Fig. 7. Saw all the keelsons, battens andmolds first, then set the blade at 30 deg. and ripthe chines, Fig. 5.

Because this boat actually has three stems—one on each side of the vee, plus a third runningdown the center of the tunnel—the framing maylook somewhat complicated when you first goover the plans. Once you get into it, however,you'll find that it's actually quite simple.

Begin with the stem assembly, which includesframes 1 and 2. These frames and the two outerkeelson-stem members should be assembled rightside up, clamping short legs to the stems to ele-vate them the proper distance above the baseline, Fig. 6. First, cut the stem plate from 3/4-in.plywood.

The next step is to cut and assemble the twoouter stem-keelson members, Fig. 1. After coat-ing all mating surfaces with glue, secure the two3/8-in. plywood gussets (per stem) with 1-1/4in.No. 8 nails, then drive three 3-in. No. 12 screws

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Page 6: Sports Boat, Build a Sleek

into the fore end as shown, one from above andtwo from below. These should be countersunkslightly to allow for fairing.

When the glue has hardened, join the 2 x 2outer keelson to the stem assembly with glue andtwo 3-in. No. 12 screws. Now notch frame 1 tofit the bottom stem member, and with legsclamped to the two outer stems, slip frame 1over them and check the fit. Next, position thestem plate, on these two stems and mark theirlocation on it. Then, if everything fits to yoursatisfaction, remove frame 1 and the stem plate,coat all adjoining surfaces with glue and returnthese parts to position, fastening frame 1 to theouter stems with two 2-in. No. 10 screws perjoint, Fig. 1, and the stem plate to the ends of theouter stems with two of the same size screwsper joint.

Before securing frame 2 to the outer keelsons,turn the assembly upside down. Coat all matingsurfaces with glue and drive one 2-in. No. 10screw through the frame into the after end ofeach stem assembly.

Next, add frames 3 and 4 using glue and one3-in. No. 12 screw per joint. Finally, secure the

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Page 7: Sports Boat, Build a Sleek

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transom to the outer keelsons with two knees,Fig. 2. Coat adjoining surfaces with glue and at-tach with three 3-in. No. 12 screws—one throughthe transom beam, one through the rear of thetransom and one through the outer keelson.Then secure the plywood gussets with glue andnails, clamp 1 x 2 legs to the transom and toe-nail these to the floor.

The next framing member to be added is thecenter keelson. At the transom, this is attached

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in the same way as the outer keelsons, Fig. 2.Secure it to each frame with glue and one 2-in.No. 10 screw. Bevel the end to fit flush againstthe stem plate, then coat mating surfaces withglue and fasten with two 1-1/2-in. No. 8 screws.

The precut chines go on next. Cut a 1-in.piece off the end to use as a pattern for the chinenotches in the frames and saw these square toeach frame; then, with chines in position, run ahand saw between chine and frame notch to in-sure perfect seating of the chine in the notch.Attach with glue and one 2-in. No. 10 screw perjoint. Don't secure the chines to the stems yet,however, because the stems must be beveledfirst. After completing this part of the fairingoperation, bevel the ends to fit against the stemsand fasten with glue and one 2-in. No. 10 screw.

Like the chines, the bottom battens arenotched all the way through the transom andfastened with one 2-in. No. 10 screw per joint.Position them midway between the center keel-son and outer keelsons. To simplify bending, slitabout 6 ft. of the forward end by running itthrough a table saw on edge. Then, after bevel-ing this split end to fit against the stem plate,apply glue to the slit portion and fasten withone 2-in. No. 10 screw.

Follow the same general procedure for mount-ing the sheer and side battens, but remember thatthe sheer battens, like the chine battens, shouldn'tbe secured to the stem until this member isbeveled.

Fairing the frame is undoubtedly one of themost difficult steps in the construction of thisboat, but if you exercise reasonable care anddon't attempt to hurry through this operation,you shouldn't run into any real difficulty. Prop-erly shaping the frame surfaces to insure perfectcontact between the plywood planking and theframe members will require the use of a coarsewood rasp and a jack plane.

If one is available, a Stanley Surform wood filewill speed up the job.

fair the hullFor those who aren't familiar with this opera-

tion, fairing involves laying a 1 x 1 batten acrossthe framing surfaces and removing enough woodfrom each member so that the batten contactseach one fully. Basically, it's a trial-and-errorprocess—put the batten in place, shave away alittle wood from the surface and check the fit.

It may be necessary to remove screws fromsome members to make possible adequate fairing.In such cases, simply redrill and refasten after

fairing. Filler pieces must be attached along thecenter keelson and on the stem plate betweenthe ends of the bottom framing members. Mountthese with glue and 1-in. wire nails when you aresatisfied with the fairing; however, during theactual fairing operation they will be easier toshape if you simply clamp them in place.

Planking the hull is simplicity itself. The buttjoints shown in the photos and in Fig. 2 shouldbe backed with 3/4 x 2-1/2in. plywood butt straps;fasten these to the planking with glue and 1-1/4in.No. 8 screws spaced 1-1/2in. apart. Use glue and1-1/4in. No. 13 ring nails to secure the plankingto the frame, spacing them 2-1/2in. apart along thetransom.

To avoid error, make a corrugated cardboardpattern of the planking sheets on either side ofthe center keelson in the forward tunnel portion.Then transfer the outline to the plywood.

Once the bottom and side planking has beeninstalled, you can mount the outer transombeam. Then, before turning the hull right side up,seal all seams (including planking butt joints)with 3-in. fiberglass tape and resin. When theresin has cured, you may sand and paint thebottom. However, for an extra-rugged hull whichwill be easier to maintain, it's recommended thatyou fiberglass the entire hull.

On the pilot model, we stretched a cottonmason's cord down the center of the tunnel overthe glass cloth and impregnated it heavily withresin to protect this joint. As you have probablyguessed, the tunnel joint takes the most stresson this type of hull.

turn hull right side upWith the hull turned right side up, you are

ready to install the interior framing.Note that the center keelson is braced with

short lengths of 2 x 4 cut to fit snugly betweenthe frames, Fig. 4. After installing these, coatthe contacting surface of the side molding andhull with glue, clamp these in place and securethem with 1-1/2in. No. 8 screws spaced 6 in. apart.

The motor well is next, Figs. 2 and 4. Afternotching the well beam for the deck battens, at-tach the gussets with glue and five l-1/2in. No. 8screws per gusset, then secure this assemblyinside the hull by driving three of the same sizescrews from the outside of the hull into the gus-sets on each side. Cut the two well sides from a4-ft. length of 1 x 12 and mount these betweenthe beam and the transom with 2-in. No. 10screws. To complete the well, cut out the 3/8-in.plywood bottom and fasten it to the transom

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beam, sides and well beam with 1-1/4in. nails andglue. Avoid leaks by sealing all well seams withfiberglass tape and resin.

The deck battens extend from the well beamto frame 1 and outline the cockpit. Attach themwith one 2-in. No. 10 screw per joint. The fore-deck battens are notched into the upper beamof frame 1 and beveled to fit against the stemplate and sheer battens. Use 1-1/2in. No. 8 screwsto secure them.

Fair the deck framing as you did the bottom,

and follow the same procedure for applying theplanking. The plywood floor panels, notched tofit around the side frames so as to reach all theway out to the inner surface of the side planking,must be supported by twq floor battens mountedover the two outer keelsons. These run betweenthe transom and frame 2.

Since the center keelson rises above the levelof the main floor between frames 1 and 2, thispart of the floor is elevated slightly to form astep, Figs. 2 and 4. To secure the 2 x 4 stepbeam, drive two 3-in. No. 12 screws through theside planking and into the end grain of this beam.The fore end of the step flooring rests on the1 x 2 doubler mounted on frame 2.

While it wasn't absolutely necessary, we added12 cu. ft. of foam-in-place urethane foam flota-tion under the floor and ahead of frame 1 toprovide additional structural strength. This in-creases the rigidity of the hull and its ability towithstand the tremendous pounding experiencedin extremely rough water.

now finish the hullOnce you have put down the cockpit floor, the

basic hull is complete and ready for finishing.The box-construction seats and console may beinstalled and finished later. We used a red-and-white color scheme and covered the foredeckwith a white marine vinyl (Nautolev, Du Pont orsimilar). For safety, we used a nonskid paint onthe cockpit floor.

The "trim" aspects of the boat are best leftto the taste of each builder. While you may wishto duplicate the original and add mahoganycoaming, 1/8-in. mahogany plywood cockpit lin-ing, etc., you can also substitute less expensivecoaming and line the cockpit with perforatedhardboard, or even skip the cockpit lining. How-ever, if you do line the cockpit, first install theseats and console, then make paper patterns ofthe lining to fit around these.

The seats and console, Figs. 2 and 3, aresimply boxes mounted inside the cockpit. Usecorner irons to assemble the 1 x 2 seat framing.The 14-1/2in. space between console and seat isan average measurement. Test this before secur-ing the console in place, and if more leg room isrequired, move it forward.

When you have completed the cockpit, installthe motor-well drains, hardware, motor and con-trols and you're ready for a season of watersports like you've never enjoyed before.

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