I'd like to suggest that, in a future season, we move the Chest of Fortune to the Skull of Siren Song event. Something like once the SoSS is turned in to Briggsy, a CoF is left on the ground when she disappears.
I think there are still folks out there doing the SoSS voyages intermittently, but it seems there aren't really enough to realize it's potential as a PvP focused voyage (from my own experience).
Adding in one of the most valuable pieces of loot as a reward would ensure crews are battling for the skull to secure the CoF, and would also have the advantage of the competitive voyage interactions spilling over into a race to sell the chest.
