70050Flat cut # sides sails [bolger] Sharpie sprit-boom leg-o'-mutton sail twist control
- Jan 7, 2014I fully agree with a 4 sided sail I got a LOT better results with them
cut to shape and darts...BUT,,in high winds I had one that would NOT
point.. It got me into trouble. I believe it had to much camber.. I
cut a flat 4 sided sail and it was not good either.. BUT the 3 sides
sail I am using now is working great. However I must sail it much
differently than a sail with camber.. My flat cut 3 sides sail loves a
LOT of camber and I just let slack out on the spirit boom and the sail
As far as pulling the sail in line with the middle of the boat that
was the ONLY way I could get it to point really close to the wind. I
do not do that with a professionally build 3 sides sail..BUT my flat
cut sail will out sail my professionally made sail with camber build
into it.. I am not sure why..
I did have to learn HOW to make my flat cut sail work but I love it
and it's working well..
Later I may find I can improve on it by adding a dart... I am still
experimenting at this time and loving the sail as it is..
Making this boat sail was much different than a PDR or my skiff but I
think all boats may sail differently..
I am happy with the flat sail and have made one for my Skiff and will
give that a try when I get time..
I would say, don't be afraid to try a flat 3 sided sail.. I do not
believe a flat 4 sides sail is worth my time. In fact there was a time
Sprit sails were my favorite. Those days are behind me now as I move
into 3 sides sails. Flat cut for now, maybe cut some roundness into
one later and see how it works.. Good night, Chief....
On 1/5/14, mason smith <masonsmith@...> wrote:
> Anent this subject of flat vs shaped sails I have had some interesting
> experiences. First with respect to lug sails. According to my
> the wisdom around WoodenBoat was that lug sails, as for the Nutshell Pram,
> should be flat, and, according to my understanding, Robin Lincoln made them
> flat for the Nutshells. When I rigged my earliest Goodboats for sailing, I
> had Robin make standing lugsails for me. They were, I believe, utterly
> When I needed sails sooner than Robin could supply them, I got some from
> Douglas Fowler, who put about 8 inches of draft in my approximately 72 sq.
> ft. sails. In identical boats and crews, they literally sailed circles
> around the flat sails.
> In sailing my Micro, with sprit-boomed leg-o'mutton sails, as in sailing my
> Goodboats with their standing lugs, I find that lots of draft is usually
> good, even in surprisingly strong winds, so I set the snotter just hard
> enough to keep the luff full. These sails reshape the wind even in their
> lower parts, so that they themselves alter the apparent wind greatly, at
> luff. There's more forward vector in the resultant force and less heeling
> moment. As for sheeting, I have never found a set of conditions where the
> Micro likes to be sheeted anywhere near the centerline.
> PCB has pointed out how much the cut of the sails affects the performance
> 4-sided sails. How do you tell? I have wondered whether the Whalewatcher I
> built for Pat Connor had the benefit of really well-cut sails. They are
> pretty, and that boat sails very well, but how well cut are the sails, and
> how well could it sail? There's only the one example.
> I have some experience in sailing the decked sailing canoes of the late
> century, especially Rushton Vespers. In them, the various spars of the
> antique bat-wing or "modified Bailey rig" are stiff. They are apparently
> intended to make the sails as flat as possible. Those old boats do sail,
> are great fun to sail, but it would be charming to see what they would do
> with airfoils in place of inclined planes for sails.
> Can't resist a comment on boomless loose-footed sails. I have had two
> Drascombe Luggers, which sport this kind of sails in gunther yawls and have
> a great reputation. On both of them I was so annoyed by bad, baggy sail
> shape off the wind that I rigged sprit-booms, for safety and performance.
> Spritbooms are not really convenient on gunthers but I rigged them and they
> were worth the inconvenience. On the second one, I laminated a curved
> sprit-boom that I called a half-wishbone. Instead of a snotter it was
> fastened to the mast with a little connector and a vestige of the other
> of the wishbone, if you can picture that. This juncture wrapped around the
> front of the mast and was held by a lashing that went around the after side
> of the mast, as on a windsurfer. The draft was controlled by an outhaul
> the clew, easily reached at the helm. So rigged, with decent sail shape on
> reaches and runs, my Lugger easily beat the fleet at the North American
> Drascombe meet and in match races against all comers including the much
> longer Longboats. I was given the trophy somewhat reluctantly.
> That don't prove anything about the flat vs cut sails argument but I would
> say that the shape a flat sail takes up when the snotter is loose is
> near optimal. It'll sail, agreed, but it will not yield the "supplementary
> clean gain" that a well-cut sail will. I don't consider good sail shape a
> luxury on a sailboat, and even if I made my own sails out of Tyvek, I'd
> build shape into them, and rather more than less, for the kinds of slowish,
> smallish boats I sail.
> From: email@example.com [mailto:firstname.lastname@example.org] On Behalf Of
> Chief Redelk It'll Sent: Saturday, January 04, 2014 2:33 AM
> To: email@example.com
> Subject: Re: [bolger] Sharpie sprit-boom leg-o'-mutton sail twist control
> I've recently experimented with a FLAT cut Leg Of Mutton Sprit boomed
> Sail..This was my FIRST flat cut sail but I had read that someone was
> doing it so I wanted to give it a try...
> This is what I learned...First,, the wind was about 10 to 15 miles per
> hour and my snotter is adjustable from the cockpit.. I always do that
> no matter on all my boats. So I was confident with the adjustment.
> The boat sailed crappy and would not point well at all. In fact I was
> being blown lee so I tossed out an anchor and played with the rigging.
> First. I thought it was the lee Board so I swung it back and forth but
> no sail would not p
> From my experience in Sprit Sails with darts I felt the camber was
> right if not on the TO much side so I tightened the sail some then
> some more and finally flat. NOPE. Did not work..
> Finally I decided to let TO MUCH sail out and see what happens. The
> sail began to pull..
> I was off the wind and zooming along at a nice heel. The boat was
> surprisingly active and fun.
> Then I went down wind right up into a cove came about into a head wind
> and began to tack out.
> On each tack the boat moved well giving me the illusion I was tacking
> back into the open waters BUT I realized I was NOT making good head
> way. In fact I kept arriving almost at the exact spot on the shore
> line with each tack so I realized something was amiss and I tossed out
> the anchor again and started playing with the rigging..
> Lee Board swung aft did not work so I swung it forward yet nothing was
> Then I remembered how I had to let out TO MUCH slack on the snotter to
> get it moving so I said, WHY NOT try that..
> Then I let out a LOT more camber than I would normally consider and
> pulled the sheet in line with the center line of the boat and that did
> the trick..
> She pointed close to the wind and when I once again hit the open lake
> she heeled over steeply and sailed like a dream. In fact I was moving
> faster now with all that big camber than before..
> Here, all this time I had always had to TIGHTEN my sprit sail to point
> into a stiff wind but now with the flat cut sail I was sailing
> windward with a VERY Loose Snotter....
> The trick to point into the wind on this flat cut LOM seems to be to
> have a LOOSE sail creating lots of camber and the boom sheeted near
> the center line..
> I was on the far side of the lake when the wind dropped late in the
> evening like it does most of the time on this lake.. I moved forward
> so the boat sit on the rocker and sailed her flat. The sail was
> cleated off and the rudder tied off. The boat moved slowly along but
> very predictable. Then I made a turn for the landing with a light tail
> wind.. The boat seemed to be bogged down and it was getting late in
> the evening so I sat on the same side as the sail heeling the boat as
> far over as was safe.. The light tail wind filled that big ole loose
> sail and we moved nicely along reaching the distant shore long before
> the sun disappeared..
> What I liked about the Flat Cut sail is it's FAST and EASY to make.
> Sailing it was DIFFERENT but once I caught on it worked great..
> I am not sure IF I will continue to use Flat triangle sails or not but
> I did learn they can be made to work if you fly the snotter as loose
> as you can given the wind conditions..
> Good night, Chief..
> On 1/4/14, c.ruzer@... <c.ruzer@...> wrote:
>> How about those traditional sharpie "simple but sophisticated
>> leg-o'-mutton rigs"? I knew the trick to adjust draft in the sail, make
>> fuller in light wind for more power or flatten it when the wind gets up
>> de-power it by working the snotter on the sprit-boom. I've read about
>> just about evrywhere these sails are written of too. The benefits from
>> a self-vanging sail, done so simply, and eliminating twist without the
>> bother of a mult-part kicker on the boom is often mentioned too.
>> But of course there's going to be a little bit of give and stretch here
>> there in the rig, and the usual prescription is to tension the snotter as
>> necessary to minimise the twist - but there's always still going to be
>> give - and you might be flattening the sail more than you want for best
>> performance. So what to do? Well it's so easy and elegant, and if I've
>> or heard of it I've never taken it in before:
>> "If we rig the snotter so that its height on the mast can be changed
>> underway, sail twist can be adjusted (ie. dialed in or dialed out). This
>> simple adjustment can increase speed and dampen rhythmic downwind
>> Your expensively cut modern bermudan mainsail and rig uses all those
>> dollars and complicated highly tensioned mechanisms to adjust twist, but
>> for the sharpie just use any simple way to alter the height of the
>> on the mast. Brilliant! I look forward to trying it.
>> Twist, the right amount at the right time is good. The windspeed and
>> underway the apparent wind angle too increase significantly with height
>> above water. A sail that's twisted right with the head falling off just
>> presents an appropriately changing angle of attack to the changing wind
>> angle and develops more power, is more efficient. When running minimise
>> twist to minimise oscilating vortices, no death rolls, and efficient.
>> Is this trick of altering the snotter height mentioned in 103 Small Boat
>> Rigs? That's a book I'm putting off getting - some say the best one (save
>> the best till last;). I've not seen PCB or Chapelle write about this. In
>> of his books Dynamite comments on the low angle of a sprit-boom as drawn
>> saying it would be better at tensioning the foot if it bisected the clew
>> angle. He was thinking only of how much more he could flatten the sail
>> less effort applied to tensioning the snotter and said he'd mention it to
>> PCB. I think all those 59sqft LOM sails afterward are shown with more of
>> sprit-boom angle Dynamite was after.
>> Anyway there's a few more good sharpie sail tips here: