Clash Of The Titans Achievement
"Destroy 10 Rock ships using the Crystal Cruiser."

Unlocking Clash of the Titans requires the enemy Rock ships to be completely destroyed, so killing all the enemy crew, accepting surrender or letting the enemy ship flee the battle does not count as destroyed ships.

The phrase "Rock ships" refers to the ship's class, not to its crew. This means pirate ships that are Rock-type will be included in the total if they are destroyed.

All 10 ships must be destroyed in a single playthrough.