Vault of the Damned

When it comes to loot sinking, I have an idea that might be fun and could lessen the frustration of losing the loot due to battling and/or not being able to find the loot quick enough.
So, if loot sinks it can go to the Vault of the Damned, which could be a prison/sea fort looking like place. Before players can go to the Vault, they would need to purchase a key from a trader at the FoTD or someplace similar for maybe 10-20 doubloons. The Treasury would have a few phantoms guarding it, but nothing too crazy. When they arrive at the vault, they might have to solve a quick puzzle or play shanty or whatever. Point is, they have to activate a portal that brings them to the Sea of the Damned Vault portion. Think Azkaban look, but basically it would have a bunch of vaults, and the vault with the crews treasure would have it's lantern lit with a flame of the damned. The players would need to unlock the vault with the key they purchased and ferry their loot to the entrance that has a statue that can bring the loot up topside onto a landing where it can be easily harpooned. I don't want to make it too difficult to get the loot back, but a little time consuming, (getting the key and sailing to the VoTD). Once the player has gone through the portal, a marker on the map should appear though, letting everyone know it is being accessed.
*Loot stored in the vault is based off of who's ship touched it last. So, if a crew sank you and touches all of the treasure in the water and lets it sink, it is still yours. Unless, they get it on their boat, in which case it will spawn in their vault if it somehow sinks.
*The loot stored in the player's vault despawns 10 minutes after they log out, and will only be available for an hour once it arrives in the vault.
*The loot can be accessed by whoever has the key.. So if someone steals the key you purchased, they can potentially open the vault.
*Multiple crews can be inside the VoTD at once, and can attack each other inside.
*The vault will only store 30-40 pieces of loot, going from most recently sunk until it caps, and the loot has to have sunk within 5-10 minutes of each other.. This way crews cant stack forts and then continually dump their stuff in the water.
*Loot could be devalued a tad as well, to hopefully stop people that might want to exploit this.
Hopefully people like this idea or can add to it. It was just a quick idea I had that would add another layer to the game's base.