The mod's documentation has all of that, but that is a bit of a jungle...
- suffice to say that the Cachalot is from Hitman, and is basically a shrunken Porpoise boat with a few additional cosmetic changes. So it is a "kit-bash" if you will. The Argonaut is the TMO pseudo-Narwal boat, which is basically another "kit-bash", but using the Sargo boat as its base model. It is NOT historically accurate, being too short and having after torpedo tubes, in addition to a myriad of other issues, but it "performs" like an Argonaut with slower dive times, and it has dual deck guns, though those are fake also, being copies of the 4 inch gun, renamed... the Nautilus is a "clone" of the Narwhal, which is the Bonus Mod Narwhal, used with exclusive permission in FotRSU. It was constructed by a contest team years ago, and is another "kit-bash" submarine, made from parts of others. However, one thing to remember about SH4, is that ALL of the boats are basically Type VII boats from SH3... no splitting of the prop rotations, only two non-independent engines and motors, no donkey motor, etc. It is all an illusion, in fact, it is
THE Grand Illusion!
Definitely unique boats that do not look like a Gato... well, at least, not to their mothers...
