18th century longboat by michaelpsutton2 - Model Shipways

[michaelpsutton2]

Ok so I measured the sheer on the plane a 23' radius and figured that the plank would spring back some when released so I bent a 21'

[Cathead]

Michael,

 

The curve of the sheer comes fairly naturally to the planks; I didn't pre-bend my sheer plank. I've no doubt that what you've done there will help, but you'll find that the real edge-bending you'll need comes at the bow. The planks are going to want to wrap up and over the one above them as they curve up the bow; you end up needing to put a "downward" bend in each one to accommodate this. If you can't envision it, try holding a few layers of planking parallel to each other amidships, and trying to keep them parallel as they run forward. This won't happen to the first one or two, but will rapidly start to be an issue as you work your way further down. The geometry of hull planking can be really counter-intuitive, at least it was (and somewhat still is) to me.