Unable to stretch hypalon hull to fit wooden kayak frame

[Darianaden]

Recently purchased 20+ year old wooden klepper kayak with Hypalon rubber hull. Hull had been folded in storage for unknown number of years and now has contracted to the point where the wooden frame of the kayak will not fit inside. Need to stretch out hull another foot or so - what is the best way to do that? Tried laying it out in sun and applying hot water but only gained a couple of inches. Any ideas appreciated.

Best

[Pikey Dave]

Hypalon is pretty stable, the fibres don’t have much “give”. Are you sure it’s not the wooden frame that’s expanded with age/damp?