To actually try and be helpful, there is an outfit down in southampton who used to make hovercraft skirts and who still make things like flexible water tanks for boats. Pretty tough as you can imagine with maybe half a tonne of water sloshing around at sea. Try googling for them _ I'm damned if I can remember the name. The old info I have says Hovercraft Consultants and the contact is Ian Mitchell 023 80871188,