Collection: Harken Single-Acting Integral Backstay Adjusters

Harken’s integral hydraulic backstay adjuster provides the power to optimize sail shape quickly for racers and adjust mast tension for smoother furling for cruisers. The cylinder features a built-in, single-acting pump. Every unit includes a hardcoat-anodized aluminum cylinder and pump, valve, and stainless pump handle with two attachment options: 1) a roll pin, that when installed, locks the handle permanently, 2) the roll pin can be left off and the handle may be inserted when needed, but stored separately. Cylinders include a clevis pin on both ends. A fiberglass position indicator attached to the top clevis pin slides down the cylinder as it’s retracted for repeatable tension settings. Standard eye-jaw toggles fit all Harken cylinders and are recommended on all installations. The pressure-release knob turns clockwise to close and pump, counterclockwise to release. When closing the pump, the knob cannot be over-tightened by hand, preventing damage to the valve. Release speed depends on how far open the knob is turned. Pressure relief is factory set to prevent crew from over-tensioning the backstay. Harken integral backstay adjusters come in four sizes to fit boats 9 - 18 m (30 - 60') with stay diameters of 5 - 10 mm (7/32 - 3/8").