By Hal Kelly HIS STABLE little sailboat, with a bottom like a power cat, is fast, light, T easy to build and unsinkable. The con-
cave bottom gives her firm footing, a lot of load carrying ability and little tendency to heel in an average breeze. The superior flotation makes her float high enough so that, with her centerboard up, she can handle very shallow water while skimming along. Though 14' long and with a beam of 6', she weighs only about 200 pounds. This, and her safe non-sinking ability, are a result resu lt of planking plank ing with w ith 1/2"Rigicel Rigicell, l, a new foam-type material made by Shelton, Conn., branch of B. F. Goodrich Sponge Products. The stuff can be cut
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Unsinkable Uniboat
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HOMEMADE lamp of heating element in reflector is sufficient to set curve of bottom. 81
Unsinkable Uniboat
DECK is removed after fitting, propped up for taping of seams and glassing underside.
HULL is removed from jig and battens to support decking are installed and fastened.
BACK in shop, deck is refitted and fastened. Top surface is then fiberglassed.
DEPRESSIONS from nailing Rigicell are filled and finish coat of tinted resin applied.
and trim-fitted with a razor blade, and is held in place with toothpicks during construction. A final covering of fiberglass and resin inside and out gives it a strong hard surface. Construct the frame jig on which to build the craft from two 15' 2x4's on a level surface with 2x4 cross members positioned and fastened at each station. Ribs #3, #4, and #5 will have a 12° slant. Cut this same angle in the cross beams at the corresponding stations. Ribs are cut from a 4'x8' sheet of 1/4" exterior grade plywood. The transom plus ribs #3, #4, and #5 are the same size and can be temporarily fastened to-
gether and cut as a unit with a saber saw. The transom remains solid, but the ribs have lightening holes cut in them as shown in the plan. These, too, can be cut as one unit. Rib #2 is smaller but similar in shape. The bow piece is solid. Ribs, bow piece and transom are now positioned on the jig, clamped in place in the case of #3, #4, #5 and transom until the 12° slant is checked, and then temporarily nailed or screwed to the cross members. Battens are cut from three pieces of 1"xl2" cedar 14' long. All battens are 3/4" square except the center battens for [Continued on page 102]
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Unsinkable Uniboat 82] [Continued jrom page 82] the bottom and the deck. These are 3/4"x2". 3/4"x2". Where the batte bat tens ns fit fit into int o the t he slots in the ribs, glue and nail small blocks 3/4" square squ are and 1-1/2" long to the ribs. After the blocks have been faired off even with the edges of the slots, the battens can be fitted. Secure them to the ribs and blocks with Weldwood Plastic Resin glue and 1-1/4" #12 boat nails. Planking with Rigicell starts at the transom. Where the sheets butt, the edges can can be cut at a 45° 45° angle with wit h finetooth cross cut blade on a table saw, or even with a razor blade. These butt joints overlap 1/2"and are held in place with round toothpicks every three inches. Epoxy resin can be used to cement the joints. Two 4' wide sheets of Rigicell about 5' long are positioned across the hull for initial fitting. Once secured they can later be trimmed with a razor blade. Apply epoxy resin to ribs and battens before fastening the planking sheets. Nail them in place with 7/8" roofin roofing g nails. nai ls. The large heads will not pull through. The forward part of the bottom can be covered with two full length sheets 6' long by 3' wide. The bow section has a slight compound curve which is easily
COMPLETED hull minus decking shows interior structural members, curve of bottom. 102
handled by this material. Heat it before forming. A round heater element screwed into a light socket with a photo reflector can supply sufficient heat. The sides sides are ar e easily planked with 4'x6' sheets cut in half lengthwise. These are angle-butted and cemented with epoxy resin just as with the bottom. I experimented with small fin keels similar to leeboards at the bottom of each side. Though not really necessary, I found I could sail without using the centerboard unless I was beating to windward. After the edges of the bottom and side planking have been carefully trimmed, polyester resin is applied to the bottom and allowed to harden. Next, a length of 8 oz. fiberglass 38" wide is stretched down the center of the bottom. It will overlap each side about 6". Transom and bow are also covered by it and it is trimmed to fit. Remove the cloth, apply a coat of resin to the bottom with a brush, and then reposition the cloth in the wet resin. More resin is now squeegeed through the cloth and all air bubbles are worked out. Lengths of fiberglass cloth from a sheet cut in half are applied to each side in the same way. They will overlap the bottom fabric slightly. Now the hull is removed from the jig, after the fiberglass has cured and hardened, and positioned right side up on a level floor. Use shoring blocks beneath the bottom if you have added the keel fins so that they do not touch the floor. The inside of the boat is now fiberglassed as well, a somewhat messy job, since small pieces of fiberglass are pasted between the ribs and battens. Exact fit is not necessary, and the fabric should be allowed to extend up the ribs to integrate the planking with the ribs and battens and further strengthen the craft. A brush and squeegee can be used to push the fabric scraps into position. If washed with a strong detergent soap before the resin hardens, the brush and squeege can be salvaged for further use. Mast supports are next fastened in place, rudder and centerboard are cut from from 1/2" exteri ext erior or plywood plywood,, and the centerboard well is finished off at the deck. Since the centerboard will bear considerable strain, it is well to fiberglass this board as well as the centerboard trunk. M echanix Il Illustra ustrat ted
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CENTERBOARD well must be carefully made, all surfaces luted to prevent leaks.
To form the decking, 4'x6' planking sheets are laid across the hull. Since the craft is six feet wide, the sections fit without waste. Joints are butted as before, with toothpicks holding the angled overlap together until the epoxy hardens. Sections must be cut out, of course, for the cockpit, centerboard well and mast. A 3" wide glass cloth tape is applied with epoxy resin over all seams. When the epoxy has hardened, harde ned, lift lift the decking carefully and place it on a flat surface, propped up so that it can hold its slightly curved shape. Apply resin and fiberglass cloth to the underside of the deck. Once the deck undercoating has hardened, apply epoxy resin to all battens and ribs and replace the deck in position. Then nail it securely to all framing and battens. Glass cloth and polyester resin are applied over the complete decking. When it has hardened into place, the glass is carefully trimmed around the cockpit and edges. These edges are then bound with 3" glass cloth tape and epoxied completely around the edge of the deck and the cockpit. Color can be mixed in with the resin when the hull and decking are fiberMechanix Ill Illustr ustrated ated
glassed, or the boat may be painted after completion. I used Flexion, from Flexion Polymer Coatings, Ft. Pierce, Fla. This white paint requires universal pigment for colors but adheres well and requires no undercoating. Deck hardware is next installed as shown in the plans. All fittings, as well as the self-locking kick-up rudder hardware, are available through WilcoxCrittenden Crittend en outlets. Tiller handle handle.and .and the cockpit trim are cut from a 14' length of 1-1/8x3" cedar, the cockpit cockpit trim tri m installed and the tiller rounded. Spars consist of a wood mast and aluminum sail frame. Use 1-5/8" round oak for the mast. Fir is not strong enough. The aluminum 1" tubing is 14' long for the gaff and 13' for the boom. The sail as shown, and available from Hard Sails, Islip, New York, is the right size for beginners and will provide a good turn of speed. Expert sailors can increase this sail area by 50 percent because of the innate stability of the craft. Trailering the craft is easy. Add lifting handles bow and stern if the boat will be carried cartop. An outboard plank or bracket is also easy to install on the transom, and worthwhile. When the wind drops, a light 3-1/2 hp aircooled aircooled Chrysler outboard has been found to push her along at a respectable 8 miles an hour. •
