These pirates certainly knew how to make a girl perform!

Only the pirates themselves knew the latest details, and they weren't giving out that information to the Navy.

"I imagine that if the pirates knew where my ship was, they'd have attacked me by now."

We have to assume, worst case, that the pirates do know.

The fact that the place was locked up indicated the pirates knew the value of their treasure.

The pirates over there don't know about your impersonation of me.

The pirates, of course, knew this trick as well, and were quite prepared for it.

The pirates didn't know what to make of the dog, even speculating that he was perhaps food.

The pirates know everything that's going on up here.