I am looking at buying one of the pirate ship sets, such as 6285-1: Black Seas Barracuda, however, I am concerned the parts in the set are too specialized, and could not be easily adapted to make custom creations. The three main parts are: the pieces of the ship's hull, the masts, and the sails. Are there any uses for these parts outside of making other pirate ships?
(promoting this from comment to answer, since it now has pictures)
In my experience, they're not that useful. I have a mast and rigging from 6270: Forbidden Island, and more rigging from 6261: Raft Raiders. The mast from 6261 is more useful (and has been in 20 sets) because it also has the two finger hinges, which make it a bit more versatile than the two mast pieces of 6270 (first part [8 sets], second part [3 sets]). The mast platform is quite reusable, given its generic shape.
All the pieces apart look like this:
And you can combine the small rigging and mast platform to make a rudimentary TIE Fighter:
ALL parts can be used for something other than the original theme.
There's also a rather humorous saying that goes: "All parts are space parts". It's equally applicable to any other theme.