Neil,
always a pleasure to impart information and to one as knowlegeable as youself too.
Lifeboat sails are hard beasties, my attempts to get any drwaings for them proved fruitless when I approached HQ and Adrian Clutterbuck. Now there are very few people who remember them, we should record their memories before all are lost.
They were very heavily made too, as they were going to be used in extreme weather. Our retired mechanic remembers them on the Liverpool we had, though they were never used in anger, he said that the nearest he could describe them to me was "like being made as the old canvas drogue (which was on Oakleys and Rothers) with metal hawser, rope bound, reinforcing the clew, tack and head. It was almost that they were solid, the brown coating on them making them stiff as a board." "And heavy, you'd not want to handle them once wet!"
I've just registered with that other place, so will follow your build there as well.
Aye, Kim