If you've ever read a campaign history of the Falklands War, then you know that the tradition of warrior-mariner was still alive and well in the 1980's, and many of them made the ultimate sacrifice in that short but bloody war. Most of the transports and oilers of the British task force were either units of the Royal Naval Auxiliary or STUFT ("ships taken up from trade") -- most notably the QE II. They were manned by merchant marines. It makes for some fascinating and inspiring reading.

Incidentally, one of the finest Coast Guard officers I ever knew was a graduate of the California Maritime Academy -- a merchant marine school.