Dave,

  In general, I wouldn't be against UMHW polyethylene sails like Spectra or Dyneema, which also float, particularly because they are so durable with respect to flogging and UV exposure.

  My doubts would center on stretching.  This is a very high-aspect 600 sf sail, roughly 9:1 or greater (estimate from the renderings), so there's going to be a huge amount of tension in it during gusts.  I have no experience with Spectra sails, but I've read that they have a tendency to stretch out of shape when pushed to their limit repeatedly, limiting their longevity as racing sails.

  I'm all for low-cost and simple, but that's going to be a very highly-stressed sail.  Do you think a PolySail would be able to handle the loads in a 55' x 11' unarig sail?

  Perhaps it could work on a sail with less tension like the swing-wing rig, or the softwing ( http://soft-wing.ch/ ).

        - Mike

 

I don't know what this fact might mean in the conversation about controlled self capsizing, but we've only recently discovered that the low-cost polyethylene laminate (polytarp) sails that we've been making and selling to DIY builders for the last 18 years are only 90% the density of water as opposed to Dacron sails which are between 130 and 140% as dense as water. For most small wooden mono-hull craft, at least, having a sail that floats can make a significant difference in whether the craft turtles or not. However, we have yet to do capsize tests on craft longer than 16.'  I suspect we would soon find out if the scow built by the Crystal River Boat Builders ever went over. That boat weighs roughly 10,000 lb., is 36' long, 12+' wide, and is powered by a 507 sq. ft. PolySail gaff main and a 135 sq. ft. PolySail jib. She recently did 8 knots on a return trip from Cedar Key. Crystal River Boat Builders sailing the scow "Spirit".  I think that they have additional video of that ocean voyage on Facebook or youtube if members might be interested.