As colourful and far more entertaining as the other suggestions are, I am afraid a Salty Dog, in all the contexts I have heard or read it in, is nothing more than a sailor(more often "Salty Sea Dog"). See RLS' Treasure Island. UNLESS as a youth I totally misconstrued Long John Silver's meaning when he said he was going below decks to slap a Salty Dog ..... which rather changes the flavour of the book.

Thank you to BSEED for the insight.