I just wanted to put this link up here because I ran across these stores that sell the kind of clothes you might need to buy if you just got a job on a cruise ship.
I remember when I got my job with Holland America they wanted me to wear white slacks and white shoes. White slacks were not TOO hard to find, though a little tricky in NYC in the 90s when the style as all grays, blacks and earthy reds & greens (blah). But they also wanted me to wear white dress shoes! fuggedaboutit - I couldn't find them anywhere.
Now, if you just got your first job on a ship, we don't recommend that you buy a lot of nautical-style clothes with epaulets, etc. But you may have some specs for clothes that are hard to find.
The shops below are in Ft Lauderdale, and they cater to yacht and ship crews. You just might find the hard-to-find items there:
Antibes Yachtwear : 1532 Cordova Rd., Ft. Lauderdale
Big Blue Yachtwear : 1344 S.E. 17th St. Ft Lauderdale 954-525-7840
Sebago Docksides (deck shoes): 1376 S.E. 17th st. 954-763-4057