I just built a 15' Prospector Ranger from Bear Mtn. I lofted all the dimensions out of the book "Canoe Craft" and there is some cheekiness in that area. If your building with staples it won't give you any problems holding it to the form. I did mine stapleless using the fishing line method (no holes) and it was sometimes a challenge to keep the strips tight to the forms. That's half the fun!