A more thorough explanation:

The dead-ship doctrine is a rule in maritime law that states that a ship is no longer subject to admiralty law when it has been altered to the point where it no longer serves its original purpose as a vessel.

For example, if a ship is converted into a stationary platform for oil drilling, it would no longer be considered a vessel and would not be subject to admiralty law. Similarly, if a ship is permanently moored and used as a restaurant or hotel, it would also fall under the dead-ship doctrine.

The dead-ship doctrine is important because it determines whether a ship is subject to certain laws and regulations. If a ship is no longer considered a vessel, it may be subject to different laws and regulations than it would be if it were still a functioning ship.