Well...I've been watching my DVD's, and I'm not altogether sure that the Black Rock is necessarily a pirate ship anymore.
Here comes my obsession with Patrick O'Brian novels now...
See, it LOOKS like a two-decker ship, and I counted at least 6 gunports on the parts that we saw, which is only about the back third or less lof the ship, and which would be matched on the opposing side.
If my estimate is correct, the Black Rock is at least the equivalent of a 5th rate ship of the line, with perhaps as many as 42 guns, not counting any stern chasers, and a minimum of 34 guns/cannons.
Pirates were rarely that big during the age of sail, because of the number of men required to CREW a ship that size--nearly 230 at full complement. Pirates tended to run cutters and smaller ships that were overgunned in order to keep the booty shares down.
So my guess is that this is a Royal Navy vessel that was sold out in ordinary and put to work as a transport or a merchant vessel. Merchant would make more sense given that there was dynamite--there's no reason for a transport to be carrying dynamite, much less a navy vessel, even one sailing under a letter of marque.
And merchants VERY often carried women aboard, whereas Navy ships didn't, which is critical.
If the Others are related to the Black Rock, they've been there for at least 100 years, perhaps as long as 180.
Unless of course, the set designer just though this was a cool looking ship, in which case NONE of this applies...
I'm SO Lost.