Early Cal boat mast tuning from manuals
The mast should be set straight athwart-ship in the boat and have a slight rake aft. A straight mast can best be obtained by turnbuckle adjustment while sailing to windward in a 5 to 10 mph breeze. The head of the mast should not "hook" to windward. If not straight, it would be more desirable to have the head "fall-off" slightly to leeward. This should give the mast a smooth, even curve from head to deck. Sighting along the back of the mast on each tack, from deck level, will give a comparison and indicate the necessary adjustments.
For normal cruising conditions, we recommend a "loose" rig. Thus a dock-side starting point would have the headstay, backstay and uppers just firm with lowers fairly loose. Now, the backstay may be made slightly tighter to "hook" the top of the mast aft. One should be able to stand facing the mast, reach out, and pull on any stay and see the mast move in that direction. Try to get tension on both stays equal with about 1/2" to 2" of play on the uppers and 2" to 3" of play on the lowers.
When racing, the backstay may be tightened up to compensate for the additional forward loading applied by the genoa. At the conclusion of the race, it is best to "slack-off" the amount you "took-up" on the backstay turnbuckle. This avoids setting up unnecessary strains on the hull and rig. Under NO circumstances should any of the rigging be set up "bar-tight".
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