High Performance/Low Cost Sails for
Small Sailboats
Batwing
Sail
The batwing sail is a triangular
sail that usually has two or more spars or full battens that assist in holding
out the rounded leech so that the sail has the rough appearance of a bat’s
wing. It can be constructed so that it is tall (high aspect) or compact for use
on canoes and other small sailing craft. High aspect batwing sails are
sometimes difficult to distinguish from fully battened bermuda sails, except that the bermuda
battens usually support much less roach than the batwings. In his 103
Sailing Rigs Philip Bolger points out that splaying out the battens so that
the battens look like the finger bones on a bat’s wing is actually detrimental
to the aerodynamics of this sail. Instead, Bolger suggests that battens be placed parallel to the boom both for ease of dousing the
sail and for storage. Most batwings will benefit from using the luff tie system to lace the luff
to the mast. This system allows the sail to be raised
and lowered quickly.
The main advantage of a batwing
sail is that it can be made very compact and flown on a
shorter mast than most jib-headed sails. In a small boat like the PDRacer,
flying a batwing sail instead of a leg o’ mutton on a mast of the same height
could net about 20 more sq. ft. of sail area, much of it near the head of the
sail where most jib-headed sails are least effective in catching the wind.
Below are some drawings of different types of batwing sails.
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Balough-type
Batwing |
Splayed Batten batwing |
Bolger Parallel Batten Batwing |
Battens for these sails are best made from ash or mahogany lathing strips about 3/16” x 2” x 8’. I make a cut down the middle of my strips so that they are about 7/8” wide, remaining flexible, but not easily broken. To cut down on sewing batten pockets across the width of the sail, I reinforce the sail where the ends of the battens will be, place grommets at these points, drill holes in the battens, then use heavy duty zip ties to hold the batten ends in place. Strips of industrial strength Velcro along the batten and on the sail near the center of the batten can also help hold the batten in place on the sail face. Hint: just cut the zip ties along the leech when you want to roll up your sail around the mast.
If I really want to
do a good job, I will use the doubled polytarp weld from a scrap piece of tarp
to form a “real” batten pocket across the face of the sail. First
I will sew up a sleeve for each batten, then I will roll the sail and stitch
the sleeve down to the face of the sail. For a hard use cruising sail to use on
lonely voyages like the
I am currently working on a small canoe batwing based upon the following sail plan. I will post photos of the build when I get my new camera. I dunked the one I was using at the 2009 Worlds.
PolySail International
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This page updated on 5/22/2009