Two fleets hide on two grids. Take turns calling out squares to fire at, and be the first to sink the other side's ships. That's the core of it. The Campaign then bends the rules a little differently in every battle.
Each side has a 10×10 grid of water. You can see your own ships but not your opponent's. On your turn you pick one square on the enemy grid and fire. The game tells you whether it was a miss, a hit, or a hit that sank a ship. Then it's the other side's turn. A ship sinks once every square it covers has been hit.
It runs in any modern browser on a phone, tablet or computer, with nothing to download or install.
A full fleet has five ships:
| Ship | Squares |
|---|---|
| Carrier | 5 |
| Battleship | 4 |
| Destroyer | 3 |
| Submarine | 3 |
| Patrol Boat | 2 |
Some Campaign battles change the fleet. In one you're down to a single patrol boat, and in another you've lost your carrier.
Ships can sit side by side, but they can't overlap. When every ship is placed, confirm your fleet to start.
When it's your turn, tap any square on the enemy grid you haven't fired at yet. Hits and misses stay marked, so you can see the shape of the hunt. Normally turns alternate whether you hit or miss. The exceptions are explained in the battle descriptions below.
A six-battle story campaign against the computer. Each battle has its own goal and a twist on the rules, shown on a meter at the top of the screen (an oil price, a ship margin, a round count or an ammo supply). Your progress is saved in your browser, so you can come back to it.
Traditional rules, no story: five ships each, one shot per turn, and the first side to sink the other's whole fleet wins.
Play a real person using Classic Battle rules. Host a game and send a friend the room code, or use Find an Opponent to be matched with whoever else is looking. While you play you can trade messages over Comms, and when the game ends you can ask for a rematch. If nobody's around, you can keep playing the computer while the game keeps looking for an opponent for you.
A new puzzle every day. See below.
Oil starts at $104.90 a barrel. Every enemy ship you sink pushes the price down, and every ship you lose pushes it up. Each round is played until one fleet is sunk, and the price carries over to the next round. Drag it back to the pre-war $72.48 or lower to win.
Fought over a ship margin that starts at 0: enemy ships you sink raise it, and ships you lose lower it, and it carries over from round to round. Build it up to +4 to win; fall to −4 and you lose.
Each side has just one ship: a two-square spy boat. Whoever sinks the other's boat first wins the round. The first side to lead the round record by three wins the battle.
Your fleet sails without its carrier and is worn down. The ship margin loses a point or more at the end of every round, and the enemy keeps firing after each hit while you still alternate turns. Reach +4 before your fleet falls apart.
One hit sinks any ship outright, for both sides, so hiding your fleet well matters more than ever. Reach a ship margin of +8 to win.
Best of three rounds, with only 35 shots per round to sink the entire enemy fleet. Run out of ammo before the job is done and the enemy finishes off your fleet.
Everyone gets the same hidden enemy fleet each day. Your goal is to sink all of it in as few shots as possible. There's no opponent firing back, just you and the grid.