I jumped to the conclusion about it being a pump boat, since That sky periscope tube was way up front and high; when I built my 32nd P boat in 1990, that's where my "pickup tube" for my pump was located. Only after I saw your WTC photos did I realize you were going to be using soem sort of compressed air/gas system.
OK- here's what I mean about the pressure hull and casing. If you look at your hull, you'll notice the the casing that was added over the pressure hull (what actually becomes the forward hull- I'm speaking of the U shaped area in front of the saddle tanks) on the 32nd P hull shows the pressure hull being "higher" in profile than the forward casing/hull. In other words, that gentle hump is reversed on this hull...the outer casing was added OVER the pressure hull- the pressure hull should not be higher than the casing. It's somewhat subtle, I'll admit. But I point it out because if you are going to add rivets and weld lines, you may as well fix this problem. I would do as John Schagane did, and build up the forward casing with a mask, and then add some putty/paint to make it higher than the pressure hull. I hope this explanation helps.
what were once vices are now habits