My 58' Hatteras was a 49-passenger inspected vessel at some point not long before I bought her. At first, I thought of it as an improvement, but as I got comfortable in the shoes of being the owner and caretaker, I quickly realized how bad it really was to have something that was refitted in that regard, post-manufacture. I would NEVER buy another one like that again, unless it had been built to be an inspected vessel from the get go.
The worst feature of the whole ordeal was what had to be done to the engine rooms for fire suppression purposes. An additional 4" was consumed from the space on every wall, including the ceiling, making access around the 92 Series Detroits in an already tight engine room (the 58 was originally designed for 71 Series and the 92s don't fit well in there) even less appealing and very difficult to access certain things. I don’t even have room to pass my knee through the doorway without having lift my leg over one of the cooling pipes. Anyway, inside that 4" space was rockwool insulation, and over that, they laid sheet metal. The sheet metal was laid in such a fashion that it was screwed and rivited in an overlapping fashion, beginning on one side of the ER, and wrapping around to the other. And guess what??? All of the hoses (and hose clamps!), electrical, plumbing, etc. was behind all that making routine maintenance impossible without disassembling the entire room. We couldn’t even get to the shaft hose clamps without hours of disassembling, and they were leaking badly. And all of this was done in the name of “safety.” Yeah right - I disagree right there! I found myself the nearest dumpster and loaded it up. And then I stopped the seawater from pouring in through the broken hose clamps at the shaft once I could get to them from behind all the rockwool and sheet metal. The unwanted byproduct of the certification is that the yacht had to be renovated in such a manner that critical maintenance could not be performed and critical elements could not monitored, but the USCG inspector got to check all the boxes on the list, and I suppose that was more important.
Five years later....I’m still pulling that crap out.