I'll admit I know next to nothing about boat design and there is a need to keep the higher parts of the boat as light as possible, but I am concerned that there are no longitudinal ribs or carlins at the mid-point of the cabin roof (deck). No need to add anything at the companionway because the hatch sill will support that area, but I'll be walking on the plywood on the two sides and it is a fairly wide expanse of 1/4" plywood. I plan to walk near the edges, more or less on the toerails, but I'm afraid some doofus might jump right in the middle of the deck some day and do some real damage.
Has anyone felt the need to add ribs in line with the hatch sill and out to the hull sides? It would be pretty hard to fashion the templates and attach the ribs, but doable.