Can gold from the Gold Capture ability be used to build a fort?
If this ship wins a boarding party, she may capture the crew with the highest point cost instead of eliminating it. This captured crew becomes cargo worth its point cost in gold when unloaded at your home island.
If a player uses the Altar of the Loa UT to force an opponent’s ship to explore an island and the Castaway UT is found, I assume that the Altar user chooses which crew is brought into the game based on this line from the Code? (because the Castaway ability only even happens because of the explore action itself)
The owner of the ship may choose to reveal and use abilities normally, however, if the ability applies specifically to the action you have given to the ship you determine how it is applied.
Castaway: “Place any one crew with point cost 3 or less on this ship, using standard cargo capacity rules. That crew assumes this ship’s nationality. Remove Castaway from the game.”