Forty berths. One flood.

A buy of 0.005 ETH or more draws one ticket. Its number is sha256(txhash) mod 1000 + 1 — fixed by your transaction before anyone can see it. Nobody picks. Buying again draws another.

Tickets rank lowest number first, ties to whoever the chain saw first. The fortieth is the waterline. Below it you are boarding; above it you are drowning. It moves every time someone draws.

At one fixed block the forty lowest board and are sealed on the boat with their wallets. Every other ticket goes on the memorial. Buys after that block draw nothing. The manifest is never touched again.

No ETH or tokens are ever sent to a boarder. What you get is your berth, or your line on the memorial.