A Photo & Discussion Forum for Wharram Design Enthusiasts
The Melanesia plans call for the spars to be fitted to their jaws, then pinned and lashed together. No mention of epoxy is made, that I can see, but the recommended shape of the joint strongly resembles a scarf.
Can this be right? Are we really supposed to merely pin & lash the spars together, and expect that to hold up? Or is it take as a given that one should epoxy the joint, and also pin and lash it?
I suspect that I'm reading the plans correctly, and that my disbelief is a sign of my ingrained Western distrust of traditional construction techniques. But before I go trust the rig, I'd like to be certain that I'm not simply missing something obvious. Thanks,
lashing is incredibly strong, done correctly, and worth nothing if not. Having built a whole 25 foot boat out of lashed together sticks, i have some knowledge of this. And i sail with crab claw. All lashed together. Epoxy is cool too, but frequently not necessary. A good constrictor knot well applied in #72 nylon cord with 600+ pound breaking strength beats a screw on stainless hose clamp in every situation i have ever encountered. Best of luck to you. By the way, are you using a flying claw? or the pincher fixed at the base of the mast style?
Thanks, Clif. I've played with lashings a bit and have some respect for them, I'd just never asked one of my lashings to hold up to anything on this scale before. So, to clarify, you think I'm reading the plans correctly and that the joint is meant to be pinned and lashed only. Right? If the plans say it'll work that way, I'm game to try it out.
I'm afraid I don't understand your question there at the end about the flying claw -vs- the pincher style. I plan to step the upper spar on the beam, and the lower spar will mount on the upper, using natural jaws in both cases. Does that answer it?
no, sorry, the idea of the 'flying' crab is that the pincher comes forward of the mast, being hauled up to the bow, then on a tack is taken around the mast to the other side. This allows it to shift the center of effort as well as center of dynamic gravity as you may require. i guess not usually done that way on a wharram.
practice your lashing on a test bed of some sort until you get comfortable with the product. It will lower anxiety about it all.
You guys will like these photos of Glenn's rigging on Manurere' "foreclaw."
Here the spars are in action on a starboard tack. Of course, after the thousands of sea miles Manurere has seen over the past few years, Glenn may have tweaked the rigging! No pins or scarfs here. . .
actually it is the lower innu (innuit) tribes who used sleds. The word eskimo is offensive to innuit people as it is a statement of resource poverty as it means 'raw meat eaters (too poor to have fires)'.
These sleds are lashed, The lower lashings on the runners go through the wood. Almost all other lashings are into grooves or over deliberate bumps for holding. There is flex, but not much, and only in specific areas (in actual innuit handmade sleds) where bone is used as a shim/bearing surface.
my umiak is skin on frame boat (25 foot - 300 pounds naked = no amas or flooring et cetera) made in the style of the innuit 'womens' boats. All lashings, bent cedar in lieu of bones. But hell of a boat and never had a lash break, but i have broken ribs in my skin on frame kayak. Not the skin, and not any lashing, but wood will fail when smashed by south puget sound currents against rocks.
but yes, the innuit were master riggers. Had to be, had nothing else, much like the polynesian people to whom they are related in language and culture. The innuit had a saying that only one knot, and 3 turns to any join. The did allow 'set knots' where a constrictor knot (in leather) was 'staged' or prevented from shifting by a stop knot, usually a square.
i rode in 1958 in a sled that could carry over a ton of cariboo meat and me, and only occasionally groaned.
Kim & Hans, I'm especially appreciative for those photos. They really do help - if much larger boats like Manu Rere or Ontong Java can function with lashed spars, then it's a non-issue on my little toy boat. I'll start practicing, as Clif suggests.
(and what amazing bamboo Glenn is using for his spars!)