I’ve just released rules version 1.5.0 with one important change: the addition of an alternative ending:
The game ends when all treasure has been reclaimed and all the island face cards have been replaced by Jacks, or at any point there are no facedown cards on the board.
I’ve realised that someone can artificially extend the game indefinitely if they’re holding the final Jack. If they want to keep the game going, it’s probably because they have a low score, and therefore are likely to not have a ship weighed down by treasure and therefore less manoeuvrable. They could then potentially dart around the map without being caught for a long time before another player can catch them.
This is a viable strategy in some ways: it forces the other player(s) to risk burying treasure in order to take on more crew cards and find that vital final Jack. If it goes on for too long though it’ll become boring, so this rule adds a final stop gap: if there are no face-down cards left then the game is automatically over.
In theory a player could keep burying treasure to avoid this, but then they’ll run out of cards quite quickly which would make them vulnerable to an attack, so hopefully this will put paid to delaying tactics.