From Longman Dictionary of Contemporary Englishshipmateship‧mate /ˈʃɪpmeɪt/ noun [countable] TTWWORKERa sailor’s shipmate is another sailor who is working on the same ship
Examples from the Corpus
shipmate• Hal could do this when necessary, but most of his communication with his shipmates was by means of the spoken word.• The crew were all old shipmates of previous cruises.• And Charlie Mallender is exactly that: an old shipmate.• Naval husbands, she said, were loyal to their shipmates ahead of kith, kin or country. 