When Being Landlubber is (Quite) an Insult
For East Coast folks, there's a phrase "daghak mu" [or 'kamu (orang) darat' in standardspeak]. It means unsosphicated / uncultured which is quite fitting for a maritime community since being land-bound means you are not exposed to a lot of things.
Furthermore, in the olden days it will also imply that one had never been to another city since you need to sail to get anywhere.
Landlubber was also historically used with contempt so the best translation for "daghak mu!" in English would be "you landlubber!"