Mashup Trimaran (continued)

Big fork. I just joined the site and am keenly interested in your project and pulling for you to get it completed. I just took possession of a tornado 20 hull and two 5.5s and plan to build a tri this fall/winter. Please keep the updates coming and best of luck!

 

Big fork. When you floated your boat, what was your gut feel on the strength of your wooden cross beam? Adequate, stronger than necessary? I understand it hasn’t been tested under load but curious if you wished it was beefier or if it was overbuilt. Thanks!

 

Well well fine folks of the forum . I'm reviving this thread as it seems easier than a new one.

So I'm currently finishing the cradle that will hold the center hull on my trailer. I used the spare Hobie 18 float as a male mold. My next move is to think about the standing rig where I might go with Dyneema. I'm using a Hobie 18 mast/sail but need custom numbers for the stay lengths. I'll use the Hobie 10 hole shroud adjuster at each float so I have some "adjust ability" if my soft line measurements/fid work are not perfect. My finish line lengths will aim for the middle of the 10 hole shroud plate.

So...Thoughts on size of dyneema? 3/16"? 1/4"?. I just bought a fid kit and the Sampson splicing book to learn how to do an eye splice. I've done them before but it's been a while. And is Fisheries Supply the best source for 60' or so feet of Dyneema?

Lastly, I want to add a structural carbon (?) tube running between the fore and aft beams. The location of the tube stock would be between the float beam section just outboard of the hinge location. I want to eventually string a hammock style trampoline mesh or re-purpose some Hobie trampoline to run from the cockpit combing out to the carbon tube. Imagine sitting with arse on the trampoline, carbon tube behind one's back, cockpit combing beam behind/under the knees, legs extending into cockpit sole with feet braced on the far side. The distance from the aft to fore beams (same as length of cockpit) is about 7' (without looking at my notes). The trampoline may be trucker tarp...not sure if I'll aim for tight (Hobie tramp style) , or slack (hammock style). Either way, the tramp will slack-up when the floats fold up.

What diameter ID and OD carbon tube stock would work to span 7' between front and rear beams as a trampoline support? Expensive but strong for weight, is carbon tube stock the best thing to use here? The box beams are 4" tall (thick) where the tube stock would fillet/glass in. As so much of this is wood, I contemplated building another 4" box beam to run between the arms, but thought tube stock would be nice and easier to just install instead of create. A strong box beam here would carry walking weight but I'm not sure I need to move about on the boat this way. I can move fore and aft in cockpit or outboard down the float. (Thinking out loud here) but it just needs facilitate the seating position behind one's back or butt. In addition to sitting here, I would also like to use this area outboard of the cockpit to lay a sleeping bag. There would be two spots to lie down: one on the port and one on the starboard, boom tent over everything. I haven't given much thought to the potential for trapeze on this contraption but one could trap off the float or perhaps off the tube stock if it was strong enough.

Picture shows potential tube in red, trampoline material in green.

thanks forum folks!! I might actually get some trial sails in this summer The never-ending Covid project is still alive!!
bones.