I have a suggestion for a mechanic or two that would make the PVP aspect of the game more exciting, while giving an opportunity for other players to cash in on the high level of skill that comes with the playstyle. This mechanic would increase the risk and reward for crews that accept the challenge.
Part 1: Reaper Points
For this to work, the game keeps track of how many player sinks/kills a crew gets with a point system. For this example, let's say that you need 100 Reaper Points. Any new ship that gets sunk will award 10 Reaper Points, sinking previously-sunk crews award 5 points, and player kills are worth five points each. If the crew manages to kill the same player again, they will receive one less point than before, down to a minimum of a single point. Scuttling/Sinking that crew's ship resets only the kill penalty. When a crew fully disconnects, all points and sink/kill histories are reset.
Part 2: Glorious Bounties
At 100 Reaper Points, wanted posters would appear by the docks to alert other players that a major threat is on the seas. At the same time, a well-sought-after "Glorious Bounty" chest will appear next to the mission table on the ship. The chest will be marked on the map with a timer for all to see. This chest can be sold by any player except for the crew that received the chest to any company for a relatively high quantity of gold (i.e. Captain's Chest levels or higher) and some reputation for that company, as a thank you for protecting their emissaries.
Part 3: When the timer runs out...
If the Bounty Ship manages to keep the chest from being stolen and the timer runs out, the Glorious Bounty becomes a "Reaper's Bounty", the Bounty Crew can now sell it at the Reaper's Hideout only. The crew who sells this chest gets double the gold and bonus reputation. When the chest is sold, the Reaper Points for that crew reset.
Part 4: Putting it in practice
Let's say that a crew is focus-firing on a single crew. They reach 100 Bounty Points (albeit slower than looking for another crew) and a Glorious Bounty appears in the ship. At this point, there are two options: Either keep and protect the chest from other players until the timer runs out, or throw the chest overboard and allow the chest to be a contest point for players to fight over.
The crew keeps the chest which is marked on the map for all to see. Wanted posters for the bounty with instructions on how to turn it in appear on the docks. New players avoid the mark on the map while experienced crews (and those who have nothing to lose) track down the chest.
Let's say that the timer runs out and the chest upgrades. The crew loses no time in navigating to and reaching the Reaper's Hideout (since selling the chest to any other company/turning themselves in is not possible). However, a blockade of reaper crews who are interested in the larger bonus are waiting for them. The final phase of the bounty begins, where the crew with the best skill walks away with the small fortune, and more respect from the Reaper's Bones.
Part 5: Other scenarios
There are a lot of opportunities for the tide to change, and where player choices affect the dynamic. For example, a Reaper Crew that pursues this point-based chest may want to start an Alliance with other Reapers, only for them to stab them in the back at the last second and take the entire reward for themselves.
You could have a crew that is disinterested in the bounty and the risk that throws the chest overboard, which turns that point on the map into a naval battlefield. The same could happen if the ship is sunk by a Kraken or something else.
In conclusion, this system allows for great risk and reward, and gives the best PK crews an opportunity to prove themselves on the high seas.