Mast Stepping and Tuning Instructions



1. Before stepping the mast check all standing rigging lengths against the checklist

2. Check all mast light wiring, be sure the masthead anchor light, steaming light and deck light function. The wires exiting at the base of the spar should be taped up to prevent damage when the spar is set on the step.

3. Prepare to step the mast in the following sequence:

a) Check all rigging lengths and inspect all end fittings.

b) Attach all shrouds, forestay and backstay. Tape clevis pins and spreader tips, check all halyards and secure to mast.

c) Check mast wiring and mast light wiring at mast step.

d) Before mast contacts maststep casting make electrical connections at base of mast for mast lights and-check circuits.

e) Tune rigging at dock and when under sail.


Pin all of the shroud turnbuckles to the chainplates and get them hand tight. Connect the headstay and backstay with the turnbuckles 2/3 open. After the crane is clear adjust the headstay so the spar is vertical fore and aft or has up to 1 degree of rake. Take up the backstay turnbuckle hand tight.

The goals of tuning the mast are-

1. Mast is in the center of the boat and strait athwart ships.

2. Leeward shrouds loosen slightly as the boat heels 15 deg +.

3. Balanced helm or slight weather helm.

Center the mast.

Until the mast is strait do not use wrenches on the turnbuckles, hand tightened is fine.

Check that the mast is in the center of the boat

Pull a tape measure up to the masthead with the center forward halyard or a jib halyard. Measure the distance from the masthead to a reference point on the shear of the boat directly abeam of the mast. Check the other side and then adjust the upper shroud turnbuckles to get the measurements even, port and starboard, then re-measure.

Starting with the lower shrouds and then any intermediates get the mast strait. At this point you will only need to get them hand tight.

Walk about three or four boat lengths away from the boat and sight down the centerline of the boat, confirm that the rig is strait.

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