Yachtie: Anyone who wears white pants anywhere near the boat. (For women: Or high heels.)
Cruiser: Someone who lives aboard and travels and doesn't spend much money
in the places they visit. (AKA "Cruiser Trash" which is, mindboggingly, not an insult.)
Boater: One who boats. Day-tripper, out for a day of fun, not a lifestyle.
Sailor: Two possibilities: 1. Sailboat racer
. 2. Someone who wants to be associated with "sailing" and therefore owns a sailboat, but doesn't actually get the sails
up. May never actually get the sailboat off the dock
(FD: None of these are mine, "I'm just the messenger".)