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Hidden Fleet Tips: Finding the Hidden Fleet Against the Clock

Updated October 2026

Hidden Fleet is a logic puzzle with a stopwatch attached. A fleet of straight ships is hidden in a square grid, the numbers along the edges tell you how many ship cells each row and column holds, and you have a fixed amount of time to solve as many grids as you can. Good puzzle technique is only half the game; the other half is knowing how this particular version builds and checks its grids, because that tells you what every grid guarantees and where to look when you stall. This guide covers both.

The clock, the grids and the fleets

A run lasts 150 seconds in total. The clock starts when you press Start, not when the page loads, and there is no time bonus for solving, so every grid you finish simply adds one to your score. The timer is tied to real elapsed time, which means switching away from the game does not pause it. The time display changes to a warning state in the last 20 seconds.

Grids get bigger as your score rises, and each size has a fixed fleet:

The fleet for the current grid is drawn under the board as a row of small ship shapes. It does not tick off the ships you have placed, so keep your own count.

What the hint cells tell you

Each grid opens with a few cells already revealed and outlined in gold. These are locked; tapping them does nothing. The game picks about 9 percent of the cells at random as hints, which comes to three on a 6×6 grid, four on a 7×7 and six on an 8×8, occasionally fewer because two picks can land on the same cell. In our simulation of several hundred generated grids, roughly one hint in four was a ship cell and the rest were water.

A revealed ship cell is drawn with its true shape. A round piece is a whole single-cell submarine, so every cell around it is water. A piece rounded on one side only is the end of a ship, and the ship runs away from the rounded side, so the cell beyond the rounded end is water and the cell on the flat side is ship. A square piece is a middle segment: the ship continues on two opposite sides, and the line it lies in is decided by the counts and the space around it. Read the shape before anything else, because an end or middle hint often places two or three ship cells at once.

How a solution is checked

You never press a "check" button. After every tap the game tests your ship cells, and the moment they satisfy all the rules, the grid flashes and the next one appears about half a second later. The rules it checks are:

Water marks are ignored by the checker. They are a note-taking tool for you, not part of the answer, so you never need to fill the rest of the grid with water to finish.

The checker tests the rules rather than comparing your grid with a stored picture, but that makes no difference in practice: before a grid is shown, the game runs a solver over it and only deals grids that have exactly one valid arrangement, adding an extra hint in the rare case it cannot find a unique grid quickly. So every grid can be finished by deduction alone. When two placements both look possible, one of them breaks a rule further on; look for the row, column or ship length that rules it out instead of guessing.

A fast solving order

With so little time, a consistent order beats clever inspiration. A good sequence for each new grid:

  1. Zeros first. Every cell in a row or column with a clue of 0 is water. You can skip marking it and just keep it in mind, but on bigger grids a few quick water taps prevent mistakes later.
  2. Water hints. A water hint in a row or column with a high count tells you where the long ships cannot pass. Use it to split lines into segments too short for the biggest ships.
  3. The longest ship. The 3 on a 6×6 grid or the 4 on larger grids needs a run of free cells and a matching amount of count in one line, or one cell of count in each of several consecutive lines. Often only one or two places remain.
  4. Fence each ship. Once a ship is placed, every cell around it, diagonals included, must be water. Fencing removes options from the neighbouring rows and columns and often fixes the next ship immediately.
  5. Count by line. When a row's count equals the number of cells in it that could still be ship, all of them are ship; when a row already has its full count, the rest is water.
  6. Single-cell ships last. They fit almost anywhere, so they are best left until the larger ships have used up their counts. What remains usually points straight to them.

Reading the clue colours

As you place ships, each clue turns green when its row or column has exactly the right number of ship cells and red when it has too many. A line with too few stays in the neutral colour. Use the colours as a running audit: a grid with every clue green that has not been accepted means your ships are either touching diagonally, not straight, or the wrong set of lengths. The most common cause is two ships placed end to end so that they merge into one longer ship, which changes the fleet even though the counts are right.

Tapping efficiently

Each cell cycles through three states with each tap: unknown, ship, water, then back to unknown. Placing a ship is one tap per cell, but correcting a mistaken ship cell takes two taps to get it back to unknown, or one tap if you are happy to leave it marked as water. Since water is ignored by the checker, a mistaken ship cell can always be fixed with a single tap that turns it into water. That one fact saves several seconds over a run.

On a small phone the 8×8 board is the tightest: cells are roughly 30 pixels wide on a 320-pixel-wide screen, so tap near the centre of each cell rather than near its edges.

Pacing a 150-second run

The first three grids are small and quick, and they are where you build your score. Aim to clear them in well under a minute together. The 7×7 grids take noticeably longer because there are more ships and the 4 appears, and 8×8 grids with a second 3 are slower again. If a grid stalls, avoid staring at it: go back to the longest ship that is not yet placed and to the lines with the highest remaining counts, because each grid has a single answer and the step you are missing is almost always there. Pressing New restarts the run from zero with a full clock, so it is not a way to skip a grid. Your best score is saved on the device, and any score above zero can be submitted to the Hall of Fame when the time runs out.

▶ Play Hidden Fleet Find the hidden fleet from the row and column counts before time runs out.