I thought I'd join the crowd and give SUP a go.
Tried a few boards and decided I needed something 8'10" X 30" X 4" and about 145 litres.
My mal is 8' X 24" , does everything I want, so will use that template stretched out to 8' 10".
Bought a block of EPS foam and away we go.
Using the bottom curve and thickness template to cut the blank profile, one of these will be used as a stringer.