The lock mechanism of the Karver K-Hook holds the top swivel aloft and is all automatic with the locking and unlocking of the sail controlled by the halyard. The head of the sail being fixed, tension in the luff is then applied through a block and tackle mounted under the drum itself.

Advantages:

• No more loaded halyard therefore halyard could be reduced in diameter
• No more 2 :1 block at the halyard, reducing the overall length of halyard on deck and saving crucial weight aloft.
• Less compression in the mast since no more halyard load All the force on the luff going directly in reducing luff sag and not holding the sail.
• No more trip line than could be in the way: automatic locking and unlocking system using the halyard.