order to select the correct PC mainsail, you will need to
determine the appropriate luff, and foot dimensions, then check
the leech length.
The diagram on
the left shows the basic anatomy of a mainsail.
The front of the
sail is the luff, which attaches to the mast, normally with luff
slides. The bottom of the sail is the foot, which attaches
to the boom at the clew. Because PC mainsails are loose
footed, there are no foot slides or ropes.
The back of the
sail is the leech. The leech of your PC mainsail has
roach, or sailcloth that projects outside a straight line
between the head and the clew. Battens are used to support
this extra fabric so that the sail does not flap in the breeze
like a flag.
The foot dimension
of the mainsail is measured from the aft face of the mast,
to a point within the range of your outhaul adjustment
|The tack ring of your
PC mainsail will be placed in the corner of the sail. The
cut length of the foot will be reduced by distance between the
luff of the sail and the bearing surface of the luff slides.
This will allow for between .1' and .25 ' of tack setback.
If your tack setback is greater
than .25', a wrinkle will appear at the tack. There are
several solutions to this problem, please contact us to
determine which method will be best for your boat.
your new PC mainsail is loose-footed, the maximum luff length of
the main is measured from the bearing surface of the tack
shackle. With a loose-footed main, tack setup is not a
concern. Because the halyard has a wide range of
adjustment, you alone are the judge of the minimum luff length.
When selecting the
appropriate luff dimension, please keep in mind the fact that
sails stretch under load. You should allow at least a 1%
allowance for stretch, 1 1/2% is better. If you have a
maximum luff of 30.00', 1% is .30', or about 4".
Please note that if
you intend to race with your PC mainsail, the sail will need to
fit within the black bands on your spars. If you do not
intend to race, you can often fit a mainsail with a longer luff
length. This is because PC mainsails are designed with a
head ring, rather than a headboard, hence backstay clearance is
less of a consideration.