Hello Robert,

I am also building a racing displacement hull SUP that if all goes well will be marketed in kit form.

One thing I did wrong- in order to save weight I put the forms 12" on center. The deck was too flimsy. I had to open it up and put ribs in every 6". I used Paulownia for the deck, and maybe a stronger wood would have been less flimsy, but still 6" rib centers for a SUP and even less where you stand is good.

I say that because the glassing schedule depends on your rib spacing. Tight rib spacing and you can get away with 4 ounce glass. The ribs provide the support. Wider spacing and you need to do 6 or more ounces on the deck. I usually use two layers of 3.25 ounce (Raka) on the deck for SUP's and then only one layer on the hull. All you need on the hull is waterproofing. You don't abuse the hull as much as you do in a kayak because you don't land the board on the beach while you are still on it like you do with a kayak. You can jump off the board and pick it up. If you expect to have more abraision you can go two layers on the hull just like the deck.

Back to the SUP I designed, when I discovered that the deck was too flimsy I first tried adding more layers of glass. Glass doesn't really help much with flex. I added two more layers of glass and only got a slight more stiffness to the deck. So going light is no issue. You just want enough to hold it all together. If you are using a deck pad, even better because that prevents deck abrasion.

Forgot to mention, I do overlap the hull and deck layers on the corners because you will bang the paddle against the rails so you want an extra layer or two there.

Looks good! keep us posted.