Ran a charter boat service for 10 years.I had to get a Coast Guard inspection every year. First boat was a 32' then a 37. both were F/B Sedans and I ran a six pack license. I did inquire about upping the passenger capacity to 12 people, but the regulations required would not make it cost effective for me. Seeing you are rebuilding from the ground up

now would be the time to up grade the licence.

I remember that a lot of it had to do with rail heights. I did get all the drawings from John Althouse owner of Marinette. He was a very nice person easy to talk with.These were needed for the up grade in capacity for the Coast Guard.
I meet with John at my boat and got a price for a radar arch for the fly bridge. This was a few years before he had a stroke.
God luck with your project.
bill