Tuning The Spars And Rigging; Tuning Under Sail - Tayana 37 Operation & Maintenance Manual

C. TUNING THE SPARS AND RIGGING
Tuning is probably the most difficult. and perhaps the most enjoyable part of sailing.
Remember, just as a car runs badly with a poorly tuned engine, your yacht will never
perform to her potential unless you learn to tune her rigging and spars. Forget all of
those rules of thumb which say that the-mast must be raked so much, the boom should
be horizontal, the shrouds should sound a perfect G when snapped with the thumb and
forefinger, or any of the dozens of others which are still current. Tuning is correct when
the yacht sails up to her full performance and is comfortable and easy to handle. There
are no other criteria.
Let us presume that your yacht is commissioned and essentially ready for sailing. The
first task is to set up your rigging and mast. Using the forestay and the backstay take all
of the rake out of the mast--it should be vertical. With that accomplished, make sure the
mast is not leaning to port or starboard. Use the upper shrouds to correct this, if
necessary. Now tighten the upper shrouds and the fore and back stays until looking up
the mast sail slot you see the first hint of an '"S" bend. Loosen the upper shrouds until
the "S"" bend just disappears--there will still be a simple bend. Using the intermediates
and lowers, make the mast perfectly straight. Check to see that it is perpendicular to the
deck. The shrouds and stays then will be properly tensioned and your rigging and spars
are now ready for a sail.
D. TUNING UNDER SAIL
Try to make your first tuning sail in a breeze of ten to twelve knots. Put the yacht hard
on the wind with sails sheeted hard in. Look up the mast and see if there are any bends
or curves--there shouldn't be. If you see a lateral bend, use the shrouds to straighten the
mast. After a few tacks your mast will remain straight.
Next put the yacht on a close reach, say 60 degrees from the apparent wind and test your
helm for weather helm. You should have either a neutral helm or a very light weather
helm. Remember, if you have anything other than a light helm in light to medium
weather, helm can get out of hand when the wind really freshens. If you find "excessive"
weather helm, rake your mast more forward using the forestay and backstay. When the
feel of the helm is satisfactory your mast is probably at or close to its optimum raked
position--you should not worry if the mast rake is actually forward rather than aft.
It is important to note that weather helm is essentially a function of the position of the
center of effort relative to the position of the center of lateral resistance. While the
position of the center of effort can be moved by raking the mast, it is also moved by the
set and shape of the sails. As you tune your yacht you will come to "feel" the differences
your adjustments make and, with patience, you will get to know when you have hit that
combination of mast position and sail set which makes her perform best. There are
several good books are on the market which describe tuning in great detail--they are
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