one for each end and a center post?
I will chime in and say that plywood boats are built with strips of plywood in an X pattern.
Ahhhh,.... No. That is not how a hot molded boat (like this) is build.
The only plywood used in the construction of this boat is for the transom. The rest of the boat is built of solid dimensional lumber, (though thin lumber "veneer" for the hull). The net result of the process is effectively "plywood" for the hull, but plywood is not used to build it.
This might help.
https://m.youtube.com/watch?v=X6hgRQuvg60
Same video you sent Sam and he linked in post #18.
loved the video