Funny story woody,
I offer an opinion that the Coast guard is not responsible for inspecting and verifying that every boat on the water meets some sort of structural or seakeeping requirements. They should make sure all boats are registered, lighted, and equipped with safety gear. (lifejackets, flares, horn, fire extinguisher) Failure in those areas makes them a danger to other out on the water.
The coast guard does offer to certify a boat or design. The designs can by certified by the Coast Guard Office of Design and Engineering Standards. Submit your design pay the fee and get your certification. If you want to take it to the next step you can certify the boats by allowing Coast Guard inspectors to inspect your facilities, manufacturing methods, quality methods, and the boat you want certified. Boats I had certified (lifeboats) then had to pass performance tests; as they should if you need a lifeboat the damn thing better work. All of the above adds cost to the boat and gets you a hull sticker, maybe some piece of mind. In my opinion, totally unnecessary for the recreational market.
A quality builder will design to pass the CG requirements just not pay the fee. If there is no certified design why bother with an inspection. If some puts crap out on the market well its buyer beware. Likewise is someone build their own boat you could buy a certified design, pay for the inspectors; and end up with a certified boat. Probably cost 5 times as much. Otherwise you could buy plans from a known designer (Farrier), build to the plans and have a nice boat for a lower cost than buying from a boat builder.
Well here in M’erica we can design and build our own boat. So long as we have the required safety gear we can use and enjoy our creation. Of course if I was to spend $30,000 on materials you think I’d spend $20 on book on yacht design.
Then I could put my $30k in materials together in a way that won't end up looking like tidal wave debris.