Sea Battle strategy: hunting, targeting and hiding your fleet

Sea Battle looks like a game of luck: you can’t see the other fleet, so every shot is a guess. In practice, some guesses are much better than others. A player who fires at random needs close to the whole grid to find every ship, while a player with a plan usually finishes in well under half of it. This tutorial walks you through your first game and then the three skills that make the difference: hunting efficiently, targeting after a hit, and placing your own fleet so it is hard to find.

What you will learn

• How a turn works on this site, from placing your fleet to the last shot
• Why a checkerboard pattern finds every ship with half the shots
• How to finish a ship quickly once you have hit it
• How the no-touching rule gives you free information
• Where to hide your own ships, and where not to
• A short practice plan using the three computer levels

Your first game, step by step

1. Open Sea Battle, choose vs Computer and Easy, and press Start game.
2. Place your fleet. The Carrier is already selected in the dock under the board. Tap a cell to put it there; the cell you tap becomes its top or left end. Press Rotate to turn it down instead of across. The next ship is selected for you, so keep tapping until all five are on the grid. If a spot is not allowed, the game tells you why: ships may not overlap, and by default they may not touch.
3. Not sure where to put them? Press Random fleet. You can still move single ships afterwards: tap a ship to pick it up, then tap where it should go. Undo takes back your last placement.
4. Press Ready. The computer places its fleet, and the big grid becomes its water.
5. Fire. Tap a cell to aim and tap it again (or press Fire) to shoot. A dot is a miss; a cross on a red tile is a hit. With a mouse, one click fires.
6. Watch your own fleet in the small map beside the board. The computer’s shots appear there: dots in the water, crosses on your ships.
7. Keep going until one fleet is sunk. The roster next to your fleet strikes out each enemy ship as it sinks, so you always know what is left.

Hunting: the checkerboard pattern

At the start you know nothing, so you are hunting. The key fact is that the smallest ship covers two cells. Picture the grid as a chessboard. Any two cells side by side always have different colors, so every ship, whichever way it lies, covers at least one dark square. If you only fire at dark squares, you are guaranteed to hit every ship at least once, and there are only 50 dark squares instead of 100.

You don’t have to follow the pattern in strict order. Jump around: a few shots in the middle, then the corners, then the gaps between. Opponents who watch where you fire learn nothing useful, and you still never waste a shot on a light square while hunting.

The pattern can grow wider as ships sink. If the Patrol boat is gone, the shortest ship left has three cells, and firing at every third cell along each row (shifting by one each row) is enough. If only the Carrier is left, every fifth cell will do. Keep an eye on the roster.

Targeting: finishing a ship

As soon as you hit something, stop hunting and start targeting.

One hit. The ship continues in one of four directions. Fire at the cells directly above, below, left and right of the hit, one per turn. Skip any that are already misses or that run off the grid.

Two hits in a line. Now you know the direction. Keep firing along the line beyond the end of your hits. When you meet a miss or the edge of the grid, go back and fire beyond the other end.

Sunk. When the ship sinks, you are told its name, so you know its length. If your line of hits is longer than the ship that sank, another ship is lying right next to it, which can only happen with Ships may touch on. Keep targeting the leftover hits before you go back to hunting.

A common beginner mistake is to drift back to random shots after a single hit, or to give up on a line after one miss. Finish what you start: a half-found ship is the cheapest one to sink.

Free information: water around a sunk ship

With the default rule, ships may not touch, not even at a corner. That means every cell around a sunk ship is water. Don’t fire there. In a crowded corner of the grid, a single sinking can rule out eight or more cells at once.

The rule helps while targeting too. Ships are straight, so the cells diagonal to a hit can’t belong to the same ship, and with the no-touching rule they can’t belong to any other ship either. After a hit, the four diagonal neighbors are always water.

If you turn on Ships may touch, none of this applies: ships may sit side by side, and a sinking tells you only which ship went down.

Thinking in probabilities

Strong players go one step further than the checkerboard. For each cell they ask: in how many ways could one of the remaining ships cover it, given every hit and miss so far? Cells in the open middle of the grid can be covered in many ways; cells boxed in by misses and edges in very few. A gap of three empty cells between misses can’t hold the Carrier at all.

You don’t need to count exactly. Look for the biggest open areas of water you haven’t searched yet, and fire into their middle. This is roughly what the Hard computer does, with exact counts.

Hiding your own fleet

Good placement makes the other player spend shots. A few principles:

• Spread out. Ships clustered in one area are found together. The no-touching rule already keeps them apart; use the whole grid.
• Mix directions. If all your ships lie across, a player who finds one quickly learns how to search for the rest.
• Avoid patterns. Ships placed in a neat diagonal, along one edge, or one per row look clever but are easy to spot after two or three hits.
• Use the edges a little, not a lot. Edge cells are covered by fewer ship positions, so searchers often try them last. A ship or two along an edge can survive a long time, but a whole fleet on the border is quick to find.
• Don’t repeat yourself. Against a friend, change your layout every game. People remember where your Carrier was last time.
• Random fleet is fine. If you are not sure, random placement is never a bad choice. It has no habits a human opponent can learn.

Common beginner mistakes

• Firing at cells next to misses while hunting, instead of keeping the checkerboard pattern.
• Leaving a hit unfinished and going back to hunting.
• Firing around a sunk ship when ships may not touch.
• Placing every ship in a straight row, or every ship in the same corner.
• Forgetting which ships are still afloat. The roster beside the board is there to help.

A practice plan

1. Play two or three games against Easy and concentrate on one thing: never fire on a light square while hunting.
2. Move up to Medium. It uses the same checkerboard search and finishes ships properly, so you need to do the same to keep up. Count how many shots you need and try to beat that number next time.
3. Try Hard. It counts possible ship positions exactly, so your placement matters as much as your shooting. Experiment with spreading your fleet out and mixing directions.
4. Play a friend with the pass screen on the same device, and try the Extra shot after a hit option for a faster, wilder game.

For the complete rules, including the variants many families play, see the Sea Battle rules guide. When you are ready, start a game.