The Sunless Rift

You can't have a second copy on board. Once you have claimed one, you can't launch another, make progress at your opponent's copy or claim it: it is scored only once.

While this card is on board, for both players: a Stowaway cost, a Salvage or Resurface you pay for (with steam, a dig or a destroy) and Refuel each need {2} more generic steam. A Salvage or Resurface that only waits for its trigger stays free (802.9). Once the expedition is claimed, it works from the logbook for the rest of the game, for the player who claimed it, whoever launched it: "you" is then the claimer (304.5a).

Crew dispatched here on their own turn make progress, whoever launched it; on the opponent's turn they can only fight (706.3a). The first player to reach 12 progress claims it and gains 3 spoils.