One of the S-21 "Maria" submarines was sunk during a skirmish with separatists, suffering serious internal damage. However, a team of adventurers towed the wreckage to the Novy Petersburg shipyard and essentially reassembled the submarine's interior. The new version was named S-21R "Maeve."
Original submarine:
https://steamcommunity.com/sharedfiles/filedetails/?id=3651204916
