2–20 captains share one board. Fleets are placed at random and the board grows to fit everyone.
2–20 captains play on one shared board.
Each fleet: one 4-decker, two 3-deckers, three 2-deckers, four 1-deckers.
The board is the smallest square where every fleet together fills at most 1/5 of the cells.
Ships may touch — no gap is required between them.
Fleets are placed at random. Everyone must approve the layout, or anyone can request a reshuffle.
Players fire in turn. A hit lets you fire again; a miss passes the turn.
The last captain with an unsunk ship wins.