Lock

Any pirate may lock any ships that they own to prevent them from being either used / emptied or sunk by the rest of their crew, no matter what crew rank. There are three levels of locking
 * Personal Use: Only the deed-holder has officer privileges as long as they themselves are ranked officer or above.
 * Crew Use: All officers in the crew have officer privileges, but only the deed holder may enter sinking blockades, flotillas, Imperial outposts, or sea monster encounters with that ship. Any officer may, however, enter non-sinking flotillas. Setting a ship on Crew Use does not prevent any crew officer from charting and sailing that ship during a time of war.
 * Battle Ready: All officers in the crew may sail into sinking blockades, flotillas and sea monster encounters.

The vessel can only be locked from the navigation table. Note that the vessel lock does not affect access to gunnery or navigation puzzles. Officers and above in your crew will see a padlock symbol corresponding to the level of locking on the dock screen on from the Vessel Report and pirates aboard a vessel will see it on the vessel panel.

If a fleet officer or above in a crew steps on board a locked ship that belongs to a deleted pirate, the ship gets automatically unlocked and the market bidding table allows him to retrieve the deed.

Historical Note

 * Before, ships could not be locked.
 * Before, there was only one level of locking, which was equivalent to Personal Use. Unlocked ships could be sunk without the owner's knowledge.
 * As of the lock status can be seen from the Vessel Report via the "Where are my vessels?" button

On the Crimson Ocean it was not possible to unlock or lock ships. Only the holder of the deed could set a course, set sail, or trade commodities. This was in order to prevent theft of commodities.