Highfield lever

To make it work in this application, the backstay is led through a block or fairlead along the deck to a two-legged, second order lever mounted with its fulcrum above deck level.

The end of the runner is attached to a cross-member between the two legs and part way along the lever.

When released, the amount of slack in the runner is therefore twice the distance of the attachment point from the fulcrum.

It is not necessary to have great leverage as the adjustment is made at a point in the manoeuvring of the boat when the rigging is slack.

The significant point is that the lever should be designed to take up the required amount of slack.