Thanks Roger, very good suggestion.

I mould a piece of thick solder wire around the shape I want then place it on the ply and draw round it with a pencil. Works every time and is re useable

Roger
Kent

This may be silly but if you push the hull into sand to get the shape of the hull, you could then lay a plastic bag or polythene in the hole made by the shape of the hull, you could then pour in some plaster Paris (not sure of the spelling !!) or a fibreglass liquid to make a mould which you could keep.
I know silly idea%uD83D%uDE0A%uD83D%uDE0A
Steve.

Easy and cheep, us a cornflake type cardboard box, cut to the right shape with scissors then transfer to plywood to make the stand

Many thanks for the quick reply and tip. I have one of these that I had forgotten about. My hull is very large but I could do the section profile in stages using this tool.

There is a device that makes it simple

http://www.wilko.com/all-hand-tools/wilko-contour-gauge-5in/invt/0209036

one example there are others this allows you to copy the profile of your hull. This profile need not be a tight fit since its a good idea to have some form of padding ( draught excluder sponge strip etc. ) between the support and the hull to prevent scratching.