Mate

Does anybody know the origins of the naval word "First Mate" ?

The sea-dog who runs the ship be the cap'n - and he be surrounded by his 'mates'. As he needs a deputy when he is 3 sheets to the wind on grog - his best mate - his 'first mate' - is relied on. ye can also be having bosuns, cabin boys, powder monkeys and all kind of able seamen.

It could be that the 'first mate' is the one he turns to by preference on cold winter's nights far from land and the company of either women or skate.

weigh anchor & heave-ho me hearties!
Set sail for the six seas!
(there used to be seven, but we don't talk about the dead sea).

I can't tell you about First Mate. But...

MATE -- "A friendly word meaning two who break bread together, or more precisely meat -- two who share meat. From the old Teutonic word 'gamaton' -- 'ga' implying a conjunction, plus 'mat' for meat. Other people think it comes from the French 'matelot,' or sailor." From "Salty Dog Talk: The Nautical Origins of Everyday Expressions" by Bill Beavis and Richard G. McCloskey (Sheridan House, Dobbs Ferry, N.Y., 1995. First published in Great Britain, 1983).