This sub is very well built with most every thing bolted on in a way you can get to what ever area you need to for maintenance. Mostly stainless steel fasteners are used and 3/8" plus thick fiber glass top deck fairing's make it feel really robust. The top deck has a very aggressive type of texture I have not seen before, for walking traction in salt water. You can see a couple pics of the stainless steel exhaust valve used for the diesel engines, and the heavy duty lifting brackets that look much like the ones Paul used on Alicia. Also the S1 01 has a bolt together rear hull section for easier access to replace and/or work on the engine, like Paul used in Alicia and Carsten used on his Euronaut, except this one has the nuts, bolts, and flange on the inside of the hull since there is no side fiberglass fairing's.
I wanted to see this ship mostly to see how Paul designed and build the top conning tower, with it's section of a tube of acrylic. I know he had several rods holding it down tight on the seals but I didn't know much else. A couple of years ago I had a design for a hyperbaric fish tank and or medical hyperbaric chamber for pet birds with this basic design. I want to see how strong the supports behind the tube section area was to help support the acrylic in case of hitting a boat or log with the conning tower. I still think I would have a couple of stainless steel bars arching up to the top of the conning tower from the top of the main deck in front of the conning tower. The black tube section above the acrylic is steel and the back area of the conning tower is fiberglass. Paul is known for making his hatches pretty light so you don't really need a lift spring.
Both the front view port and the conning tower acrylic have a little bit of localized crazing, so they might need to be replaced in the future. I don't know if they can be re-annealed or not or how much strength is lost when there is crazing, but I'll read up on it in the near future.
I have more pictures then are on the Frapper site and better quality ones of the ones I have on Frapper, so if anyone wants them I'll do what I can with my slow dial-up internet connection. There is what looks like a iron ball in the most rear area of the stern that I'm guessing is for helping balance the sub for a better center of gravity.
For the top bearing of the rudder there is what looks like four half inch thick by perhaps 3" X 3" pieces of marine plywood or some sort of composite sandwiched together that has a vertical hole drilled in them to receive the top rod of the rudder, sorta like a bearing. I should of gotten a pic of that. From what I under stand there is a large sorta hard ballast tank inside the hull just behind the conning tower pilots seat. I'd like to know better how that ballast tank works. There is at least two drop weights on the keel and lots of zinc blocks. The fifth wheel trailer wheels have sealed bearing protectors for backing into water.