It seems like no matter what I do, I can't manage to capture enemy warships. If they surrender, they don't show up in the dialog under "captured" after the battle. I've tried to move in with much more powerful ships (with a least a 2-1 superiority in manpower) and capture by boarding, but while the two ships are grappled together, the enemy ship keeps firing into the hull of my ship even while they're being boarded, often times sinking it. I don't want to respond with my own cannon for fear of sinking the ship i'm trying to capture. Any advice?