SAIL VOCABULARY: WHAT DO ALL THESE TERMS MEAN,
AND HOW DO I KNOW WHAT REALLY MATTERS TO ME?
For technical questions about sails, please email to: email@example.com
Headsail Size by Percentage: Headsail size is generally
described as a percentage of your boats foretriangle area (the triangle made by
the deck, mast, and headstay). A 100% sail fills the entire triangle, but does
not extend past the mast, anything more than 100% extends past the mast. The
higher the percentage, the larger the sail is. While there are some other
variables due to changes in design as the sail gets larger, a 150% sail has
about 50% more sail area than a 100% sail.
Headsail Size by Sail Number: Sometimes headsails are
described by their number within the sail inventory, especially on race boats.
This system avoids confusion by eliminating the percentage description of the
sail altogether. The #1 is the biggest headsail, the #2 next, then the #3 and
so on. As a general rule a #1 would be a 150% to 153% Genoa, a #2 would be a
130% to 135% Genoa, a #3 would be a 100 to 105% Jib, a #4 would be about 85%,
and a #5 would be a storm jib. The #3 is also sometimes referred to as a
"Blade" because it is designed for upwind work in fairly heavy wind and is cut
very flat. The 100% Jibs we sell are not cut as flat as a blade because they
are designed to work well in a much larger wind range, giving a more all purpose
Crosscut: A sail with the seams running horizontally across
the sail. The most simple and basic (and least expensive) construction, still
used on most woven Dacron sails.
Radial (or Tri-Radial): A sail with the panels cut so that
they radiate out like slices of a pie from each corner of the sail. Radial cut
sails allow the sailcloth to be placed so that the loads on the sail are better
aligned with the strength of the cloth, this allows lighter cloth to be used
while maintaining performance and durability. Radial cut designs are much more
common when using laminate cloth as the design gains are bigger, and the added
cost is more easily justified in a more premium sail.
Mainsail Slides (or Slugs): Small plastic slides that are
attached to the mainsail with webbing or plastic shackles. Slides can be fed
into the mast track when you rig the boat and then kept in place with a sail
stop or mast gate cover. Slides make raising and lowering the sail quicker,
safer, and easier, and allow the option of running your main halyard aft to the
cockpit so you can raise the sail without leaving the cockpit.
Bolt Rope: The rope sewn into the edge of many mainsails to
allow them to be fed directly into the mast or boom. All Mac mainsails come from
the factory with a bolt rope and no slides. These sails need to be manually fed
into the mast every time the sail is raised and dump out of the mast onto the
deck when they are lowered. While there is a very small performance gain to a
bolt rope sail, most non racers (and some racers) find the convenience and
safety of sail slides to be well worth it.
Loose Footed: A mainsail that is attached to the boom at
the corners only (no bolt rope on the bottom of the sail), this lets the sail
have a better airfoil shape all the way to the bottom and makes the outhaul
easer to adjust, All BWY exclusive mainsails have this upgrade.
Shelf Foot: A feature on some mainsails that allows the
sail to hold it's shape all the way to the bottom almost as well as a loose
footed sail. These sails have a section of lightweight cloth that matches the
airfoil shape of the sail sewn to the bottom edge so that the sail is not pulled
flat to the boom.
Ropeless Foot and Luff: Historically most sails have
been built with a rope sewn into both the luff and foot of the sail to allow it
to be fed directly into the mast and boom. Unfortunately the rope adds weight
and bulk to the sail and worst of all, they shrink up over time and reek havoc
with sail shape. With sail slides and a loose footed design, this rope is no
longer needed. All BWY Exclusive mainsails use reinforced Dacron edge tapes that
eliminate the troublesome rope.
Cunningham: A ring pressed into
the luff edge of a mainsail just above the tack. This allows a block and tackle
to be used to pull down on the sail to flatten it as wind builds.
Jackline: A system that allows the
sail to be easily reefed without having to remove the lower slides from the
Power Head: A mainsail that is wider at the top than a
standard sail. These sails have more “roach” area outside of the triangle formed
by the mast and boom. On boats with fixed backstays the difficulty of tacking
the sail past the backstay limits the amount of roach that is practical. On the
26M you can add as much sail area as you want since there is no backstay, all
our 26M sails have more roach than a conventional sail, we also offer a flat top
sail for the 26M
Flat Top (or
Square Top) Mainsail:
These sails can be used only on boats without a
fixed backstay. Flat top sails have more sail area than standard sails, but
more importantly they have much more chord, or width, at the top. On a
traditional triangular sail the top several feet are largely useless because the
sail gets so narrow that it produces nearly no power in that area, by making the
top of the sail much wider it produces lift all the way to the top. Square top
sails work like adding several feet to the mast height without adding nearly
that much sail area.
Full Battened: A mainsail with battens that run
horizontally all the way across the sail rather than being just a couple of feet
long at the back edge of the sail. Some designs use two full battens at the top
to support the roach of the sail (especially on power head and flat top sails)
and partial battens lower in the sail. Full battened sails can be easier to
stack on the boom and are quieter when tacking in heavy wind, but are somewhat
UV Cover: A strip of UV stabilized Dacron or Acrylic fabric
sewn to the edge of a roller furling jib or genoa to allow it to be left on the
furler without a pull up sock to protect it. Sewn on UV covers make life very
simple (no sock to put on after you get back to the dock), but add to the weight
of the sail which hurts light wind performance, shorten it’s life somewhat, and
do not provide dirt and abrasion protection while trailering like a sock type
cover does. We recommend White UV Dacron for the sewn on cover as it adds less
weight to the sail than acrylic and has much less detrimental effect on sail
shape and performance as the sail ages.
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