Fastening System

The start of the fastening system is 15 gauge stainless (316) steel staples. The planking has to be held in place while the epoxy drys, and these do a great job. I tested stainless nails, but they did not have the holding power that these narrow crown staples have, in the sense that the 3/8 ply would pull right by the nails.
Remember, this hull will have two layers of 3/8" doug fir marine plywood, the main reason being that I can lift a 4x8 sheet comfortably. Scarfs are also easier. So the first layer is epoxied to the frames, and must be held in place while it drys. But you want to minimize the fastener impact because the second layer will get screws that go through both layers. Hence the light gauge stainless stables. The fact that they are stainless assure that they will not become a rusting problem later on.
SO, THE BOTTOM LINE, IS THAT THE STAPLES HAVE GOOD HOLDING POWER. BUT NOT MUCH "PULLING UP" POWER. So if you push the plywood up tight to the frame it will probably hold with the staples, but the staples will not pull the plywood up tight on their own. For the aft quarter, at the very bottom corner by the transom, I had to pull that plywood in with a screw (with washers to form a clamp) , but once in I shot a couple of staples and it held fine, even when I immediately took the screw out. So I did some pragmatic testing today. In the photo is the $24 dollar Harbor Freight pneumatic stapler, and a few staples into the bulwark. These would not come out when I pulled the test plywood back off. UPDATE - I SCRAPPED THE STAPLES - USED SCREWS WITH WASHERS BECAUSE I COULD COUNT ON THEM PULLING UP THE PANEL - SEE PANEL PHOTO.