A Photo & Discussion Forum for Wharram Design Enthusiasts
hi everyone i have just read scott williams latest excellent blog and he suggests making tiki 30 beams for the tiki 26 as it is far less complicated to glass and all the structural bits are inside the beam itself.any help or suggestions would be appreciated as always.
The locating pads on the deck that the beams sit on are best made of serious stuff, imho. Vaea's were scary looking! They had been made up to height with 3/4" (19mm) and 1/4" (6mm) ply of some sort. With all that end grain, they sucked up water like a sponge! When I glassed the forward beam, I discovered they were really ugly: I smacked them hard with a hammer and popped them right off! The 1/4" piece was still epoxied to the deck, but the 3/4" piece was totally wet and going rotten.
On Vaea, the locating pads are all teak now. . .
Good point, Kim. I made all mine somewhat oversized and out of solid teak. Well worth it.
Multihulls are like backpacks. You take care of the ounces and the pounds take care of themselves. I'm a decentant of the Piver designs, and weight will ruin the boat. If you over engineer the beams, perhaps building the hulls from 9mm instead of 6mm would be a good idea in case you get rammed by a horny humpback. Where would it stop?
As for the spliced plywood for the web on the beams: Its acting mostly in shear not bending. it's there to keep the top and bottom chords apart and from moving independantly.
As for the the triangular shape: That really sucks, there's got to be a better way. A larger top chord would be a great addtion to sit on.
Well, Thomas, you bring up an interesting alternative. But I might suggest a W18x100 for the savings in weight and the lower windage. And I do believe with either of these solutions the dolphin striker could be eliminated. And, of course the cockpit depth could be increased by a like amount, but the additional submersion of the hulls might require a redesign of the motor mount and an extra short shaft (XSS) outboard. I would still recommend glassing and epoxy coating the surface of the beams for salt water resistance, unless they were either corten steel or asphalt coated.
I'm working on the flexible hull to bean connections now. I believe if they are lubricated with relative bearing grease and lashed on with fallopian tubes the whole structure will work nicely.