Battleship Hunting and Target Lock
Efficient hunting has two phases: find the first ship with a parity scan, then lock onto its axis after a hit. Firing at random cells usually costs many more shots.
Parity scan first
The smallest ship is two cells long, so checking every other cell cannot miss every ship. Cover one checkerboard colour first, then switch once you find a hit.
Use probability density
When several ships remain, prefer cells that fit the most possible ship placements. The AI uses a probability heat map; human players can apply the same logic by eliminating impossible cells.
Lock onto the axis
After a hit, fire at the four neighbouring cells. If two hits line up, continue along that axis; after a sink, clear the surrounding cells that can no longer contain a ship.
Open the endgame
With one or two ships left, strict parity can leave gaps in the corners. Switch to full coverage of unknown cells so the last ship cannot hide in an unchecked square.