The S-42 is a small clone of the S-18, so uses all of the same files for the 3D artwork, and similar files for the upc and other text files, which some do have some minor alterations, but nothing that changes the overall operations of the boats in any appreciable amount, including dive time and depth, as well as speed and turning. They are almost identical in that regard, with about the only obvious difference being the conning towers used and when they appear... In real life, the S-42 "Class" was a bit newer than the S-18 Class, but not by more than 7 years, which when it comes to rust, can make a huge difference...
