Someone mentioned moving between ships at the same location before, well to extend this:
When two ships meet at sea you could use grappling hooks to attach one ship to another and stop it escaping, perhaps while grappled ships cannot move.
Then you could move between ships and attack the occupants.
To get away the occupants would have to remove the grapples: a project that works like picking a lock, or maybe like a normal project the progress representing untangling the grapple.
You could allso attack over a small distance using missile weapons to fire between ships.
The only troble with this is, in my opinion, that you can try and get rid of the grapple, working on the project, and fight at the same time, but in RL life fighting and trying to perform another task like that is next to impossible, so the solution I see is to make fighting a project where two combatants become engaged in a swirling melee. (finer points of how a system like that could work would probaly be best discussed elsewhere, in another thread)
(BTW, guess who saw "Pirates of the Carribean" last night
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