Overview
The game is a turn based two-player game where each player is represented by a fleet of submarines.

The setup phase
At the beginning of the game, each player will have to position his or her fleet of submarines on the board of 10 x 10 squares. Setting up takes place in the sides assigned to the players. Each player has his home in the board located directly above his tab.

The setup process can be dealt with manually, or the player can chose to let the game do the setting up automatically.

Automatic setup
The submarines will initially be positioned randomly on the board. At any time the player has the opportunity to repeat the automatic setup process by clicking the "SHUFFLE" button in the drop down panel. This action will simply result in a new randomly generated sub marine setup that ensures a legal board state.

Manual setup
If the player wishes to manually position the submarines, her or she can simply drag'n'drop the subs around the board, but only a single sub at a time. When the sub is being dragged around a marker sub will appear below the active sub, indicating exactly where the sub will be placed. The active sub will change color to indicate where it is legal (green) and where it is illegal (red) to drop the sub. If the sub is dropped in an illegal position, it will return to the previous position as indicated by the marker sub.

A selected sub can be rotated by clicking the "ROTATE" button in the drop down panel or by clicking the right mouse button while the cursor is over the sub.

Finishing the setup The setup phase must be ended within the time limit, which is the same as the turn time limit set in the game set-tings prior to game start.

When the board is ready to use, the user can click the "DONE" button in the drop down panel. This will end the setup phase and the game will wait for the opponent to finish his setup. If the player fails to finish the setup phase within the time limit, the game will automatically position the fleet, and to the game.

The game phase
In each move a player must place three targets before sending the move to the opponent (by clicking the "SEND MARKS" button in the drop down panel).

Placing shots takes place in the board located over the opponent's tab.

There are two different types of shots:

• Depth charge bombs
• Sonar pings

There are two way of setting targets: Either by dragging the targeting pieces to a square or by clicking on a square. The second way, however, only places depth charge bombs. To place sonar pings the player must drag them to the board. The player can move the targeting pieces around the board until he or she is satisfied with their position.

In each turn, the player has three deep charge bombs at his or her disposition, and throughout the entire game each player has three sonar pings at his or her disposition.

Deep charge bombs
These bombs will damage any sub intersecting with the square at which they were fired.

Sonar pings
A sonar ping reveals whether any of the opponent's subs intersect with the square in which it was fired and the 8 squares surrounding this target square. Dark gray squares indicate that no sub intersects with this square, while a red square indicates that a sub does indeed intersect with this square. It is important to note that a sonar ping does not damage opponent subs, but merely reveals their positions.

Sonar pings can optionally by disabled when setting up the game in the matchmaking lobby.

The control panel
During the game phase there will be three buttons in the control panel:

• UNDO MARKS: Used to undo the positioning of all marks this turn. Will be available when at least one shot has been positioned. To undo single marks, simply drag each mark back above the board
• SEND MARKS: Used to fire the shots at opponent's fleet. Will only be active when all three shots have been positioned or in the single case where no other pieces can be placed on the board.

 
The hit counters
Above each player's tab is a counter that will tell how many of the opponent's squares he or she has hit so far.

Winning the game
The game continues until one player has sunk the opponent's entire fleet by hitting every square of every sub (17 in total).

When the game ends, the positions of the opponent's subs will be revealed, and the players will have the option to play another game or return to the matchmaking lobby.