Interior design for a 23' tiller skiff

[Davesea]

I am new to the list. I am looking at a www.Calypsomarine.com 23' Pirogue (sold in the US as www.Caribiana.com which is not producing boats at the moment). I would like to design a simple interior for the calypso 23' tiller model which includes side seating for an open fore-aft deck, and floatation tanks for non-sinkablity. There are no offsets for the hull so I am trying to get some measurements.

Can anyone give me advice on how to take measurements of an existing hull and how I can plug these into a program to reverse engineer the a scaled hull shape so I can lay out the interior. I am reading "understanding boat design" but need some more practical advice on how I can assure my design will be reasonable.

Thanks
Dave