According to Andrew Drake who founded Odysseus Software (original developer of Sink or Swim for Amiga) they never received any royalties for the game. Despite this fact he was offered the chance to port the game over to the PC but refused because he couldn't afford to buy one.
This game took 9 or 10 months of hard development.
Sink or Swim's main characters are Kevin Codner and the 'Dim Passengers'. Kevin Codner is an obvious Kevin Costner spoof, but 'Dim Passengers is a Kim Basinger pun which fails due to the actual pronunciation of Kim's name - 'Dim Pay-Singers' would be much closer to her real name - they could've set the game on a cruise ship to allow for that.