[RogerBW]

All the standard Crewman skills have shown up on characters in various games I've run. The generic merchant-ship crewman in Last Days of Atlantis, several of the British secret agents in Irresponsible and Right, and of course the Age of Sail Pirate Crew. Spacer in the various space games, of course. Airshipman in Crimson Skies, but more in The Riddle of the Hills, my Edwardian steampunk one-shot. And Submariner with two separate sets of agents who ended up spending time aboard the things (the WWII spies of I&R, and the robot-fighters in Reign of Steel).

All that said, I don't think I've called for rolls against them very often. It's more a case of having spent a point in the skill meaning you can live a reasonably normal life on board the vessel in question; you don't need a crewman looking over your shoulder to keep you safe, and you don't need to stay in the passenger areas.