How to Tune a Ketch Rig

Tuning a ketch rig is an essential bit of seamanship. A poorly tuned sailing rig can force a boat to heave to in a strong gust. This is called weather helm, a dangerous situation on a lee shore. If the same gust makes a boat fall off the wind, it is said to be a lee helm and this could drive you onto the rocks. Much of the tuning work can be done from the deck. The exception is the stay joining the two mastheads, called a triatic stay. Adjusting it requires a trip aloft in a bosun's chair.

Things You'll Need

  • Bosun's chair
  • Turnbuckle adjustment tool
  • Inclinometer
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Instructions

  1. Dockside Tuning

    • 1

      Loosen the turnbuckles for the shrouds and the stays.

    • 2

      Tighten the upper shroud turnbuckles by hand until the mast is straight. Opposing shrouds must have the same tension.

    • 3

      Tighten the forestay turnbuckle by hand. Make the forestay tighter than any other stay or shroud. Ascend the mast in the bosun's chair. Tighten the backstay triatic turnbuckle by hand. Return to the deck.

    • 4

      Tighten the lower forward shrouds by hand. Secure them with less tension than was applied to the upper shrouds and the forestay.

    • 5

      Tighten the lower aft shroud turnbuckles by hand. Secure them with less tension than was applied to the upper shrouds and the forestay.

    • 6

      Tighten the backstay turnbuckles by hand to rake the mast slightly aftward. Secure them with less tension than was applied to the upper shrouds and the forestay.

    Tuning At Sea

    • 7

      Sail on a reach to windward and haul the sheet in until the inclinometer reads a 15-degree heel.

    • 8

      Tighten or loosen the tension of the shroud turnbuckles with the turnbuckle adjustment tool until you feel a bit of looseness. Go by feel, not observation of the shrouds.

    • 9

      Tighten the aft stay turnbuckles by hand until you can no longer move them, and then finish the adjustment with the turnbuckle adjustment tool.

    • 10

      Change course, sailing on various points. Adjust the back stay turnbuckles by hand and then with the turnbuckle adjustment tool so that the movement of the backstays does not exceed two percent of the mast length.

    • 11

      Change course, sailing on various points. Fine tune the stays and lower shrouds by hand and with the turnbuckle adjustment tool as needed. Adjust the upper shrouds. If the boat has a weather helm, rake the masts forward by tightening with the turnbuckle adjustment tool. If the boat has a lee helm, rake the masts toward the stern.

    • 12

      Re-tune the rig after several hours of sailing.