1
THE MAINSAIL CONTROLS
With the mainsail, we have one
or two extra controls to play with:Q Luff tension is the same
as for the headsail
Q Clew outhaul for tightening
or releasing the foot of the sail
Q Kicking strap or vang for pulling
the boom down
Q Mainsheet traveller with a car that can
be moved to windward or to leeward2
SET CLEW TENSION WITH THE
OUTHAUL AND SET TRAVELLER
Sailing close hauled in light winds,
we would want to let off the clew outhaul
to increase belly in the sail, and then move
the traveller up to windward and sheet the
main in until the boom is amidships. We will
also want to leave the kicker/vang loose to
ensure the leech isn’t over tight, allowing
some twist in the top of the sail.
Keep hands away from the car on the
traveller. Most mains have telltales near
each of the batten pockets up the leech
but actually for our purposes, we really only
need to concentrate on the top most telltale
as this is the one that is the hardest to get to
fly properly.3
CHECK TOP TELLTALE, SET SAIL
SHAPE AND CHECK BATTENS
ARE PARALLEL
We can tell if the sail is set nicely as the
top telltale will fly most of the time. If it hides
behind the leeward side of the sail and flies
forward, we have too little twist in the sail
and must ease the sheet. In light airs, we
will want twist in the sail but in medium to
heavy airs, we want to remove this twist and
flatten the sail. We will do this by tightening
the clew outhaul to flatten the foot of the
sail and trim the mainsheet until the top
batten lies parallel with the boom or very
nearly so. We can help with this by tightening
the kicker/vang, which will add tension to the
leech of the sail.4
FINE ADJUSTMENTS
It is a combination of kicker and
mainsheet tension that will flatten the
sail and get that batten lying along the boom.
Now of course the main works in conjunction
with the headsail and is affected by the
backwind coming off the headsail. If the
main starts to backwind with the turbulence
from the headsail – we see this when the luff
of the main is being pushed to windward and
means that the slot between the main and
headsail is too narrow – then we need to
harden the mainsheet until this stops and/or
tighten the clew outhaul further, to flatten the
sail. We may find this overdoes the tension
of the mainsheet and our top telltale along
the leech flies to leeward again and forward,
so we will need to ease the mainsheet and
try to prevent the backwinding by easing
the headsail sheet, to widen the slot. It’s all
a question of trying to balance the shape of
our sails so they work together.Trimming
the mainsail
If your traveller is fitted with a tackle
adjustment, making changes is
easy. If not, you will have to luff up,
then move the car across by pulling or
pushing on the falls of the mainsheetEXPERT ON BOARD