: I don't know anything about boat design but.

: I would make sure you can roll the boat or perform some other form of self rescue and handle the boat according to the conditions you expect. If you can rent a boat and then build a similiar one..

: I might lean towards adding depth rather than length - it might make turning easier.

Hi Grorge,
My original thought was towards depth rather than length. However, the lines looked rather 'plump' to be kind. I wanted a shallow draft as the area I use most sometimes only has a depth in places of about 8" to 1'.
I have designed in a little more rocker than would be normal practice and that should help with turning. There is no point in hiring a long kayak here as my ex Cape Charles is the longest in the country and is now owned by the only hire company.
They for the most part run Prion (?sic) and Roamer Rand kayaks.
Thanks for the comments

Rob