Something like rolling blank dice x amount of times in a row, or x amount of blank dice all at once to unlock the Quartermaster.
Picking up x amount of value 6 cargo in a row for Boy.
Losing a battle against a pirate to unlock Pirate.
Running into a reef X amount of times to unlock Navigator.
Having X amount of non-event encounters where you can't interact - like no anchovies, or no spice to unlock Mate.
Premise would be the player would need to experience multiple "bad" interactions/outcomes and they then get rewarded by having a crew member that would help prevent those outcomes.