Early access to Blackwake is now available on Steam, offering a multiplayer FPS with a pirate theme. This trailer (NSFW) celebrates the news with a look at gameplay from the game, which was crowdfunded via Kickstarter. Here's a bit on what to expect:

Broadside or board enemy ships as a crew with intense FPS Naval Combat based in the Age of Sail
Man the cannons and fire off coordinated broadsides with other players to sink the opposing ship. You will fight as a crew of up to 16 real players on a ship led by another player that has been voted as captain. Modes can have up to 54 players in a battle!

Coordinate and cooperate to be efficient and be a devastating crew
If you're part of the crew, you may help the ship in any way you see fit without being forced to a role. You can be the part of the gunnery crew by loading cannons and firing at the enemy, or be the master of repairs and help keep the ship afloat by patching holes in the ship, repairing sails, or pumping out water. Help keep your ship's fire power up by running supplies for your fellow crewman, or even board an enemy ship and conquer it!