Well, I have no experience with the gold edition, but in vanilla Settlers II there was a very obvious map called 'four islands' or something. A large map of one big island and a lot of smaller ones.
That said the 4th or 5th scenario of the normal campaign introduces ships and such. That scenario's called 'the High Seas' or something, iirc. Of course, that's not unlimited play... Well, it is, but you can't change settings :P
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