The term 'PREPARE FOR A DRY DOCK' can be summarized by the crossword solution 'UNRIG'. This means to take down the sails and other rigging of a ship in preparation for it to be taken out of the water for maintenance. This is a necessary step before a ship can be placed in a dry dock, which is a large basin that can be flooded to allow a ship to be floated in and then drained so that the ship can be inspected and repaired.