Designing a simple Battleship game in Python

I am trying to code Battleship. It should be a text one-player game against computer where computer and human player take turns in shooting at opponent's ships. I decided to start implementation with this part: A human types target coordinates and computer answers if a ship has been hit or even if it has been sunk. Ship positions are fixed (predefined in the program). For some time I wondered how to represent game plan and ships to get this working as smoothly as possible. This is what I have put together:

class GamePlan:

    DIMX = 10
    DIMY = 10

    SHIP_MISS = 0
    SHIP_HIT = 1
    SHIP_DEAD = 2

    SHIP_COUNTS = {
        2: 1,
        3: 1,
    }

    def __init__(self):
        self.ships = [
            [(1,1), (1,2)],
            [(5,6), (5,7), (5,8)],
        ]

    def hit(self, target):
        hit_ship = None
        hit_ship_index = None
        for i, ship in enumerate(self.ships):
            if target in ship:
                ship.pop(ship.index(target))
                hit_ship = ship
                hit_ship_index = i
        if hit_ship == []:
           self.ships.pop(hit_ship_index)
           return self.SHIP_DEAD
        if hit_ship:
            return self.SHIP_HIT
        return self.SHIP_MISS

def main():
    game_plan = GamePlan()

    while True:
        raw_coords = raw_input('Enter coords: ')
        str_coords = raw_coords.split()
        coords = tuple([int(c) for c in str_coords])
        if len(coords) != 2:
            print 'Bad input'
            continue

        result = game_plan.hit(coords)
        if result == GamePlan.SHIP_DEAD:
            print 'Ship dead'
        if result == GamePlan.SHIP_HIT:
            print 'Ship hit'
        if result == GamePlan.SHIP_MISS:
            print 'Missed'

if __name__ == "__main__":
    main()

EDIT: GamePlan should be probably called Board as answer of Janne Karila suggests. Just to clarify what I meant by that name with my flawed English.

There are a few things I a

Perhaps GamePlan would better be named eg. Board? English is not my mother tongue, but AFAIK game plan == strategy.

1,3,4: The ships are static, they just occupy some space on the board. However, a ship object would be aware which squares belong to the ship, and perhaps should be responsible to determine if it has been sunk.

2: hit is perfect; in OOP the object is often the object also in grammatical sense. Think of file.close().

5: If the player hits the same coordinates twice, you'll report a miss, which is wrong.

StackExchange Code Review Q#25541, answer score: 2