Running battens to figure out the placement of the longitudinals, which are 1/4" x 1 1/4" flat bar, notched and welded into the frames on about 12" centers. As the longitudinals progressed, they stiffened the hull enormously... at first I could stand at the scaffolding at the bow and give the stem a good hard shake and the whole thing would move like a slinky, but at the end of running the longitudinals I had a grid like, basket like structure which was very stiff. Next