The 19' shown in my book is a completely different design from the Guillemot although the 17' boat is based on the 19' boat. There are differences other than length. With my software I can create all the forms I need so I don't bother adding/subtracting or changing form spacing. I just make a new design.

However, if you want to modify the 17' foot boat to make it 18', I would just change the form spacing. You will need to stretch the end forms somewhat. Adding a form will make a flat spot. This would not be a big deal, but better to just stretch the boat.

> I want to build an 18' Guillemot for a little extra space for camping. I
> live in BC and Vancouver Island has amazing 1-3 week routes (check out
> Tofino area sometime). I have only just begun lofting the forms and my
> wood won't arrive until mid December. In Nick's book he has a 19' version
> which I assume he added an extra form. I think that I should be OK by just
> increasing the spacing of the forms to acheive an overall length of 18',
> if this is a plan that I'll later regret comments are welcome. The 19'
> Guillemot has the same width of 21" as the 17', so this looks to me
> that stretching it out to 18' will not effect the Kayaks handling.