This is the layer below the top board, or deck, of the new ama. It and the next layer down will get hollowed out something like this:
Since I made those cut-outs, John convinced me to make the sides of the boat thinner, so in the next photos they'll look different.
I don't plan to cut anything out of the bottom board, since I want the strength and also the ability to make it smaller if I want, for instance at the bow vee from the keel up to the chine.
The middle crosspiece in the above photo is part of a bulkhead that will hold the sides from oil-canning. The crosspieces closer to the ends are for strength where the akas will be attached.