December 1, 1998 Issue

Dreamboats... The Tri Blue Bird

By Richard Carsen

This is based on a model I found in a German Museum. What I have drawn is a flatbottomed boat, but in the model the three boats forming this tri had shallow V bottoms. This is a small semi-private mu-seum, which did have some very good stuff, I never saw elsewhere. It is on the Schwach-Hauser Hehr Strasse in Bremen next to, and on the grounds of, the apartments for (German) naval personnel's widows. The model was labelled as Hawai-ian.

Now, I have been told that king Kamehameha, after he had invaded and sub-jugated all the Hawaiian islands, planned to invade Tahiti and the surrounding islands. He thought that the existing double canoes which he had used for the local conquests, would be too small for such a long distance operation and he was experimenting with trimarans when death put a stop to his plans. It is my opinion that what we are looking at here, is one of those experiments, a central larger - and two smaller craft, modeled on the lifeboats of the visiting ships.

The forms were of the simplest: a double-ended craft, wall-sided, with a bot-tom sloping upwards from the keel, the plane of which was bounded by the straight keel below and the curving chine, ending at the bottoms of both stem and stern posts, that is the ends of the keel. As a kid, I had a sailing model with that shape. There is nothing wrong with it, simple to construct, and its sailing capability excellent.

I put a schooner rig on this contraption. Single outriggers sail in the Pacific with some kind of square sail that balances around a heavily sloping mast, which slopes toward the smaller hull. I saw this same sail, but reduced to a kind of sprit, in photos of a regatta at the eastern end of New Guinea, on a racing outrigger. Among the Pacific sailors anything goes.

When first sailing the Hoku'lea, the double canoe built for the centennial and sailed to Tahiti and back by Polynesian type navigation, they had it rigged with some kind of western rig. The rig was found to be highly dangerous as our rigs are not lifting but rather heeling rigs. With the exception of the Balinese triangular rig, however, all native rigs need a crew, at least one capable man or boy besides the skipper. Listening to the tales of the Hoku'lea under western sail, I knew what they were talking about. They were truly in danger.

So maybe, this tri should not have this kind of sail. Maybe it should be rigged the Hawaiian way with Hawaiian sails which will twist and turn before the wind and spill it; the sail I have shown is not excessive, but just the same. In the next issue I will show and explain this fascinating Hawaiian fan rig, along with another one, the balanced rig on the slanting mast mentioned before.

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December 15, 1998 Issue

Using Meranti Plywood and Fir Strapping for Small Boat Construction

By Bob Patterson

Two materials I have used to build small boats have been bargain priced 1/4" thick meranti (lanan) plywood and 3/4" fir strapping. Neither of these is the preferred material for boatbuilders, but are available at local home improvement centers for very reason-able prices. Bargain lauan plywood (1/4", 4'x8' sheet) goes for $6.50 to $12, while marine grade sapele or okume plywood is $30 to $45. Fir strapping costs a fraction of vertical "rained fir.

However, there is a quality difference. Bargain lauan plywood has a solid core of 80% of the total thickness, with very thin face plies, often having voids on one of the face plies. Fir strapping often includes the center of the log (avoid this) and is sometimes quite warped. To address these problems, select the stock carefully, fill any voids with thickened epoxy, and resew/laminate the strapping if necessary. On the plus side, most bargain lauan is made with good waterproof glues and the strapping is well dried.

Due to its configuration, bargain lanan should actually be treated as l/4" solid stock This means the builder must constantly he aware ot the grain orientation of the core ply. To join lengths of this material, use cross-cuts at 45 degrees and then join with butt blocks and epoxy. It is not advisable to try to scarf this material in a router/plane jig, as the thin-ness and splintery nature of the face plies pre-vents good cuts. I know, I tried.

A good technique for stack-laminating bargain lauan is to cut one layer 3/8" wider than the rest of the layers. Then glue and cure as normal, the wide layer flush to the stack on one side. Then put the protruding edge of the wide layer against a rip fence of a tablesaw and remove enough stock to create a smooth edge. Then flip the stock width-wise and cut to the finish width.

In a similar manner, to form curved shapes of stack-laminated bargain lauan, cut two patterns, Pattern A the exact size desired for the finished piece and Pattern B oversized by 1/4". Use Pattern B to cut and align pieces for laminating, and remember to stagger the joints. After gluing with epoxy and curing, tack, with aluminum push pins, Pattern A to the bottom of the stack. Then flip over and use a bottom bearing flushcut router bit to finish cut the final shape. Be careful that the guide bearing rides only on Pattern A and no drips of glue interfere with the smooth sliding of the router.

Where extra strength is needed, such as for bulkheads, a second thickness of bargain lauan can be laminated to the first, having been lightened by use of a 2-1/2" hole saw. I hope some of these ideas help some folks who are building away on their boats. Good luck.

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