controls and adjustment
1. main sail general notes
Locate a tell-tale approx. 3/4 up the leech
of the sail on the trailing edge (near the back of the W
for the sail #)
Sew the battens in place to prevent loss.
Roll the main and jib together on large plastic
or cardboard tubes to keep them smooth when not in use. These are
available from carpet stores.
Sew the end of a light shock cord to the leach
of the main approx. 12Ē from the clew. Fasten the other end to the
end of the boom. This cord helps to prevent spinnaker sheets from
getting wrapped around the end of the boom when gybing.
4 mm pre-stretch line is best for the various
control lines. Use a different colour for each service to avoid confusion.
2. main halyard
Always hoist the head of the main up to the
"black band" to keep it as high as possible. Install a hook near
the base of the mast to hold the wire halyard in place fixing the main
at max. elevation.
Install a Velcro loop on one side of the mast
support to hold the folded rope halyard.
Keep the boom free of the goose-neck while hoisting.
then attach it. Avoid stretching the luff of the main. It should
have tiny horizontal "speed-wrinkles"' extending out from the luff to maximize
power from the main.
3. main outhaul
Set up the outhaul so that it is easily adjustable
while sailing. Run control lines back under the thwart (or along the side
of the CB housing) but preferably to each side deck for adjustment while
sailing. A 3:1 or 4:1 purchase is effective.
In light wind, pull the clew of the main out
close to the black-band to flatten the sail, this helps to maintain air
flow over the sail. A tight outhaul also helps to loosen the leach
of the main. It is OK if the foot of the main folds into a shelf.
This is necessary to flatten the sail.
In medium air, ease the outhaul to make the
sail full for max. power. Just take out the vertical wrinkles along the
In heavy air, pull the clew out to the black
band to flatten (depower) the main when going to windward. Ease the
outhaul on reaches to provide increased power for planing.
4. main sheet
The main sheet should be approx. 35 to 40 ft
long and made from 1/4 or 5/16" braided line.
Fasten the mainsheet to an eyestrap at the end
of the boom. Then lead it down to a block on the traveller, or bridle,
back up to a block on the boom so as to provide a 2 to 1 advantage.
note: Then lead it forward through a stationary eye on the bottom of the
boom about 3í forward of the boom end [garrotte preventer during gybes!],
and on to a block on the boom that will be directly above your centre
mainsheet swivel block when you are sheeted in.)
Tie a knot in the main sheet so that the boom
will only touch the shroud as the knot hits the main block. This will prevent
damage to the boom or shrouds when gybing in high winds. Put tape on the
boom where it touches the shrouds to help prevent chafe on the wire and
Simple bridles are now popular in place of a
traveller car. The advantage of the bridle is that the main sheet tension
acts primarily to adjust the inboard/outboard angle of the boom. Downward
tension on the leech of the main is minimized. Leech tension is then
left primarily to be controlled by boom vang tension. A double block arrangement
is used, similar to a Laser to allow free travel along the bridle. (Alís
note: These days, most people use a single block tied to the bridle. This
makes it easier to keep the boom centred.)
Some racers switch from a bridle to a traveller
for strong wind conditions. The only advantage of the traveller arrangement
is that it can be let out to the corner in strong winds. This keeps the
main flat while spilling air to help keep the boat level. With this set
up, a strong crew can play the traveller to compensate for gusts. For this
reason it is important to have the control lines lead back to the thwart
where they can be easily adjusted while hiked going to windward.
It is critical not to oversheet the main when
going to windward. Watch the tell-tale on the leach of the main and try
to keep it streaming back*. If this
is difficult (i.e. it tends to loop around behind the main), there may
be too much boom vang tension. If the tell-tale loops around in front
of the main, there may be too little vang tension. *
Alís note: Donít overdo this, however! If you want to point, the leech
ticker should spend up to half of its time disappearing behind the main
once your boat is up to optimum upwind speed!
As the wind dies, it is very important to ease
the mainsheet. (When in doubt, let it out!) In very light air, the
boom must be out 1 to 2 feet, or more, to leeward of the center line of
5. boom vang (kicker)
Both lever vangs and block & tackle arrangements
can make effective vangs. A minimum of 8:1 or 12:1 advantage is needed
for good control.
Since the vang is the primary control of mainsail
shape, it must be easily adjustable from either side of the boat while
you are hiked out. Run a control line under the thwart to each side deck
where it can be adjusted and cleated on the vertical edge of the side deck
(Alís note: or on the aft edge of the thwart).
In light to medium wind, very little vang tension
is needed going to windward. The prime indicator is the upper batten. The
back 6 inches of it must be parallel to the boom. Too much vang will tighten
the leach causing this batten to hook to windward. This chokes the air
flow over the main. Too little vang will leave the leach too loose. This
puts too much twist in the main making it hard to point.
Although it is common to go to windward with
little vang tension in light to medium winds, it is necessary to apply
some vang on reaches and runs to prevent the main from twisting off too
much, thus spilling wind from the upper section.
Another indicator for proper vang tension is
the luff of the main. With proper vang tension, it should luff evenly from
top to bottom. It the vang is too loose, the upper section of the main
will be too full. Hence it will luff first. It the vang is too tight the
upper section of the main will luff after the lower part.
In heavy air, the vang is used to flatten the
main thus depowering it so as to be able to sail the boat flat. On reaches
where the power can be used for more planing speed, it is possible to ease
the vang slightly. This also helps to avoid a capsize by keeping
the boom from hitting the water as easily.
There is very little need for a cunningham.
It is designed to pull mainsail draft forward Ė usually when a good breeze
has blown the draft aft while you are close-hauled. It takes creases out
of the luff of the main when extreme mast bend has left the sail "luff-
starvedĒ. In light to medium airs, it is generally best to leave
small horizontal "speed wrinkles" along the luff of the main. Only
use the cunningham upwind in heavy air to help flatten the main.