Quantum STAR 2003, Tuning Manual

Page: 7 / 32

4
they sweep back more it will require a little more lower backstay but makes it
easier to get bend in light air. If your spreader doesn’t come back as far on one
side you will need less lower on that tack. Check that they are even with the
same line from tip to tip. It should be parallel to the side top of the mast butt
plug. This can be checked best by
laying a batten on the butt plug and
lining it up with the line between the
spreaders. You can also check this in
the boat by pulling hard enough on
the forward lever to bring the
spreaders back to their stops. Check
to see if they hit simultaneously. The
mast manufactures usually do a good
job with these measurements but
they can change over time.
If your spreaders don't already have a mark put a jib trim mark on the spreaders
457 mm (18") out from the side of the
mast. I use a felt tip pen or tape to put a
1" band around the spreader. In winds
under 18 knots the jib leech will line up
with this mark. In more wind it will be
slightly outside.
Before standing up the mast check the screws at the jib box, wipe the wires off
and tie on the shockcord to keep the backstays from catching the spreader tips.
Put on your mast head fly if you use one and stand the mast up.
C) Shrouds
After the mast goes in lay it forward and hook up the headstay and slide on the
lower and upper shrouds. With the right upper tension, the uppers should just
slide on the shroud track with the mast in the forward position. If the uppers are
too tight then the mast will have too much prebend in light air and the spreaders
may pop forward when sailing on a broad reach. Your shrouds will also cut in the
main going down wind. If they are too loose then the whole rig will not be
upright in the boat. The lowers should be fairly loose. Now hook up and set the
backstays. Put on enough forward lever to pop the mast in a positive bend and
check that the lower backstays are loose and that the upper backstays have the
same amount of tension. Set them at 5 units on the Loos gauge. Then by using
a tape measure hooked on the main halyard measure down to the chine to see
that the mast is centered and check the mast at the partner. I think it’s best to
have at least 3 mm (1/8") of space on both sides of the mast.
A helpful method for monitoring upper stay tension is using the small model
Loos gauge. A good starting point 23 to 24 on the new Pro Loos gauge (31 or 32