I’m desperately trying to find a fabric that has decent tensile strength and tear resistance and good hydrophobicity. Previously used Hypalon (which isn’t great, but was just about adequate for our purposes), but it’s like hen’s teeth now. Having exhausted all the normal channels I thought I’d give you lot a try. Any suggestions?

This?

Where are you sourcing your hypalon? Its used to make the collars on RIBs (Rigid Inflatable Boats) and is made by a company called Orca. There are various companies that use it in the UK, Henshaws, tidal.biz etc. An alternative is PVC wh. You used to be able to get both from here: http://www.ibs-boats.com/