Quantum STAR 2003, Tuning Manual

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7
previous experience and what input we are feeling at the time from the boat. If the
tiller is telling us that we have too much weather helm maybe the mainsheet is too
tight. Getting the trim right takes experience and experimentation.
The mainsheet is similar to the jibsheet. As we trim tighter, the twist is reduced
and the sail flattens. The mainsail flattens through increased mast bend rather
than a pulling aft on the foot like the jib. We have given that control to the
outhaul on the mainsail. What we are concentrating most on is the twist. The
general rule on the Star, like most boats, is to line up the top batten with the
boom. This means that the bottom batten points up the most with each batten
dropping down until the aft end of the top batten is parallel to the boom. In very
light air it will hook up some from the weight of the boom. In very heavy air it will
twist off a bit to leeward to de-power. This is where the experimenting comes in.
Every condition takes a little different trim. Bill Buchan felt one key to his
success in the 1984 Olympics was knowing how to trim his main. The weeks of
tuning in Long Beach before the Olympics had helped narrow down the range for
the correct place for the mainsheet. The next year in Nassau when Bill won the
Worlds he said he had started the regatta with the mark on his mainsheet moving
though a large range and through the week that range narrowed as he found the
fastest position. The key is to constantly watch the boats around you and try
different trim until you begin to learn what is too tight and what is too loose. A
mark on the mainsheet is very handy here so you can reproduce this trim on the
next weather leg or at a later date. You must be careful though because condi-
tions change and with it your trim must also. What worked for Bill in Long Beach
wasn’t exactly what was needed in Nassau.
Like all controls on the boat you want the mainsheet to be as friction free as
possible and to have the proper purchase. All new boats now have the main-
sheet going right to the transom. This gives as much leverage as possible and
allows the boom to be trimmed closer to the center line. There are two different
systems used for the mainsheet. The most popular is the single system that
starts on the aft end of the boom goes down to the boat, back to the boom,
forward to mid boom and down to a ratchet and cleat. The advantage of this
system is that it is simple and it allows a mark to be put on the line for reference.
The other system is the double mainsheet. Instead of stopping at the aft end of
the boom it goes through a pulley and goes back forward to mid boom and down
to another ratchet and a double cleat. The advantage of this system is that both
lines can be pulled simultaneously cutting the purchase in half. It is much faster
for mark rounding, jibing and pumping. When fine tuning, only one line is
pulled, giving a bit more purchase than the single system although hardly a
noticeable amount. The big disadvantage is that you make a reference mark on
the line. Whatever system you use, make sure that the blocks all line up and if
you go inside the boom, that the lead is straight. Some people have gone back
outside the boom to make sure no friction is added. If you do this put webbing
around the mainsheet so when jibing you will not get hung up.