Didn't realize they'd designed them as well as built them. One of those mini jets is my next boat project, well after I do some maintenance and mods to the ocean boat.
They saw multiple builds with issues due to all transverse stringers and virtually nothing longitudinal... they made everything longitudinal relying on the engine room bulkhead and enclosed bow to give them lateral rigidity. It works better...
They mocked-up quite a few different plywood versions before they built...
