I've been suggesting a system of sea currents long before skelleton ships came into the game and introduced some farily difficult times in picking loot from the water. With this new method, players can take their time or even have unpredictable emergent encounters, but the loot will remain in the game at all times, only requiring the knowledge of the players to know where the loot floated to through the currents of the sea.
Loot no longer sinks: As part of this new system, loot will no longer sink and dissapear, now it will follow sea currents until it hits an island.
Sea current dynamics: In the image posted above, the colors represent different behaviours in the currents. Let' go over each one:
Purple: Is the sea current that surrounds the shroud, from the furthest location reachable with a ship. Every piece of loot that falls in the shroud will always return to the main map, therefore this current is mostly in one direction.
Red: Is the sea current that repells loot. Usually loot that float to these areas will not reach the outposts, mostly meant as a protection to outpost to dissalow for loot to wash ashore them. The current will lead the loot back to the other green and yellow currents.
Green: Is the strong current that takes the loot and drags it towards the bigger islands. All major islands will be where the majority of the floating loot will end up on, making it easier to grasp the current dynamics.
Yellow: Is the weaker current that usually takes the loot towards the nearest green current, loot can hit smaller islands in the way and get stuck in them, but they have no priority.
Loot Traits: In every current, loot will move at a speed slower than a sprint-swimming player but faster than a pirate swimming while holding an item. They should maintain their glint. They should also be mindful of objects, like rocks, sea posts and outposts, and float around them in some radius. After reaching any island's shore, they should hit the beach and stay there until the game normally refreshes the island, which should be around 2-3 ingame days.
I understand that this isn't a very precise and in depth suggestion, but it's something I believe would be a positive addition to the game, allowing for loot to remain in play for longer and give players some new systems to fall back to in case of having to take massive hauls of treasure from the water without stressing over an arbitrary time limit, only needing to take heed to where the sea is taking the loot.