Patrol Boat
The patrol boat is the smallest ship in the game, which inherently makes it the easiest to sink. That small size also makes it the hardest piece to find. It takes only two direct hits to sink the patrol boat.
Submarine and Destroyer
The destroyer and the submarine are the middle-range ships. It takes three shots to sink either one.
Battleship
The battleship is the namesake of the board game. Four direct hits will sink the battleship. This may be the most familiar ship since its name is in the title, and the TV commercials usually ended with one player proclaiming, "You sank my battleship."
Carrier
The aircraft carrier is the largest ship. It takes five direct hits to sink it.