Thread: GIS Yawl

Hi Bruce, the yard is made from Cypress. It is rectangular with rounded off corners and tapered to a similar profile as MIK specifies for the round spar, just thicker. I have been extremely negligent in not adding my spar data to the database so really need to get the yard measured and weighed. It is a bit taller than wide and tapered in both planes with the thickest section being 40.5x49.5mm. From reading others descriptions I think my yard is in the medium+ stiffness category. I tension the sail to have a slight horizontal crease along the yard and when I apply downhaul the yard bends and the crease dissapears. You can see the crease in this photo: https://picasaweb.google.com/lh/phot...eat=directlink

And the bend with medium downhaul here:
https://picasaweb.google.com/lh/phot...eat=directlink

There is still a tiny bit of mismatch between the bend of the yard and the sail shape near the throat. I found this out when I replaced temporary cheap line lashings with Dynema. With the Dynema lashings tight up against the yard the sail appeared slightly too full near the front half of the yard. When I switched the lashings back to the cheap line the sail shape went back to perfect. So I'm inferring that the yard may be a bit too stiff in the front section, however this has been working so well with the cheap lashings that I'm reluctant to mess with a good thing. You can see the mismatch between the sail and yard curve in the photo above. Also the sail twist is very well controlled right now and I'm concerned that making the yard less stiff near the mast would hurt that. It almost looks like a slightly curved yard of the same stiffness would do the trick but that's a whole lot of work when a bit of string fixes the issue perfectly.



As to the cost of the sail, I'm not sure what the price is now, as mine was their first sail of this particular design (radial lug) and the loft may have adjusted the price since then. I got a lot of sail for my money and friends who have had Doyle Ploch make sails for them have felt the same way so the price is competitive with other quality lofts and less than a specialty loft like Dabbler. The guys in the loft know the Goat sail and the design is already done so call them up. They should be able to give you a quote right away. Their website: Doyle Ploch Sails

Originally Posted by Boatmik

Florida is just down the road from Maine hehehe

MIK

Hi MIK, yep it's just 1600miles (2600km) down highway 95

Simon, I'm impressed and feel that your slight rectangular shaped yard is going a long way to what the ideal wooden yard needs to be. I agree with you about not messing with it for now. However, if anyone wants to take the wooden yard development further, then I'd be suggesting going square at the front end and from just past the mast at about the mid point, start tapering to a rectangular shape where the depth is in the vertical direction. This should give the required amount of stiffness at the mast and that extra bit of curve needed at the front, while keeping enough stiffness in the top to support a tighter leech. A tiny bit of taper close to the tip where it doesn't matter should take care of the aesthetics.

For mine, if I had a long enough work surface, I'd be inclined to laminate one with a slightly negative curve, similar to a longbow before it's strung.

Here is a pic of the bend in my "stiff" but heavy alu yard with LOTS of downhaul. Very similar to yours.

Attachment 218019

As it is my yard is a hollow-box spar measuring 40mm square, no taper at all, although the ends are bull-nosed.

I am willing to experiment with shapes and construction/assembly techniques. An idea for a new boom is percolating now although it probably will become a winter project.

I'll take what you describe for a yard and see what I can come up with on paper. Probably be another winter project as building the Pathfinder may not keep me busy enough...

Bruce, looks like your sail cut matches the yard perfectly.

Originally Posted by SimonLew

HOLY, $%^&*(*&^% I want one of those!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Um, I think I may give these guys a call. I feel guilty. I should show this to my sailmaker here...he also makes a lot of racing sails.

Simon, is your yard data on the WIKI?

Originally Posted by SimonLew

Bruce, looks like your sail cut matches the yard perfectly.

I'm happy with the stiffness, but not the weight. It's a bit much kit to be carrying aloft

Thanks for the sail maker's contact details, I think I may just call them. The design looks very similar to some of the latest Optimist sails going around at the moment.

I finally got around to writing a long reply to Bruce's post (on page 29) on but I closed the page by accident so this will be shorter.

The pennants are flying as if the wind was coming from aft of the beam, but the wind was definitely coming from forward of the beam. It's possible the twist of the sail is sending the outflow and venting the pennants in another direction. (?) Look at my American flag which you can't see, since it's flying exactly behind the flag pole. Perception wise each pennant is also of different lengths and different materials, mine, for instance is almost 8' long.

So Bruce, a sailing technique question-- let's say the upper part of my sail is correctly set for my wind direction and I'm oversheeted down below-- is it better to do this, or to let the top of the sail by the lee and set the lower part of the sail for the wind?

One thing to keep in mind is I have kept m soft bendy yard on purpose due to the type of sailing I am usually doing-- solo coastal-Atlantic sailing-- I'm very happy with twist up high and a bendy yard to help the depowering. Can I stop twist with this bendy yard? At what point is the twist inevitable for me?

All in all, I'm happy with everything, so I'm not too stressed but I am always trying to improve myself.

Thinking about Bruce's suggested yard configuration:

I'd be suggesting going square at the front end and from just past the mast at about the mid point, start tapering to a rectangular shape where the depth is in the vertical direction.

My square box x-section yard does not lay flush against the mast. Rather, the corner (top corner closest to the mast) of the box section is all that contacts the mast when the sail is set. So, I am wondering - pretty much just thinking out loud - whether distinguishing vertical and horizontal directions makes any sense when describing the yard? Or how the stiffness of a rectangular sectioned yard would affect sail shape. A rectangle won't have the same stiffness in the two planes.

Not that we can't experiment with configurations... just thinking about the shapes being created (or thought of).

Originally Posted by CCBB

HOLY, $%^&*(*&^% I want one of those!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Um, I think I may give these guys a call. I feel guilty. I should show this to my sailmaker here...he also makes a lot of racing sails.

Simon, is your yard data on the WIKI?

LOL! That's been the reaction from lot's of folks who have seen the sail. I think the loft has made a few sales as a result.

My yard data is not in the WIKI yet. I've been postponing writing it up until I have something I'm happy with. It's close now so probably time to unlace it from the sail and do some measuring. Sure would be nice to have another Goat to sail against to see how the tweaks affect performance.

Originally Posted by woodeneye

I'm happy with the stiffness, but not the weight. It's a bit much kit to be carrying aloft

Thanks for the sail maker's contact details, I think I may just call them. The design looks very similar to some of the latest Optimist sails going around at the moment.

The radial Opti sails were the original inspiration for this design although, as I understand it, the cut ended up being significantly different.

Originally Posted by BobWes

Thinking about Bruce's suggested yard configuration:



My square box x-section yard does not lay flush against the mast. Rather, the corner (top corner closest to the mast) of the box section is all that contacts the mast when the sail is set. So, I am wondering - pretty much just thinking out loud - whether distinguishing vertical and horizontal directions makes any sense when describing the yard? Or how the stiffness of a rectangular sectioned yard would affect sail shape. A rectangle won't have the same stiffness in the two planes.

Not that we can't experiment with configurations... just thinking about the shapes being created (or thought of).

Bob, Initially I experienced the yard laying over on it's side a bit but found that since it is rectangular in cross section the halyard attachment point can be rotated to compensate. Not sure this makes sense, really need a picture, but my halyard is attached to the top corner of the yard closest to the mast and not from the center of the top surface of the yard. This keeps the long side of the rectangular yard mostly vertical.

Bob, the downhaul tension should keep the yard "upright" as would the leech tension. It may twist a bit, but not much.

Originally Posted by callsign222

I finally got around to writing a long reply to Bruce's post (on page 29) on but I closed the page by accident so this will be shorter.

The pennants are flying as if the wind was coming from aft of the beam, but the wind was definitely coming from forward of the beam. It's possible the twist of the sail is sending the outflow and venting the pennants in another direction. (?) Look at my American flag which you can't see, since it's flying exactly behind the flag pole. Perception wise each pennant is also of different lengths and different materials, mine, for instance is almost 8' long.

So Bruce, a sailing technique question-- let's say the upper part of my sail is correctly set for my wind direction and I'm oversheeted down below-- is it better to do this, or to let the top of the sail by the lee and set the lower part of the sail for the wind?

One thing to keep in mind is I have kept m soft bendy yard on purpose due to the type of sailing I am usually doing-- solo coastal-Atlantic sailing-- I'm very happy with twist up high and a bendy yard to help the depowering. Can I stop twist with this bendy yard? At what point is the twist inevitable for me?

All in all, I'm happy with everything, so I'm not too stressed but I am always trying to improve myself.

I'll take your word for it Christophe! I was having a bit of fun firing a shot across your bow

Most of the power comes from the lower third of the sail so it should always be trimmed accordingly and never over-sheeted by much or it will stall (Being a pilot, you'll understand this ). Over sheeting and stalling the sail is absolutely the worst thing any sailor can do unless you are Paul Elvstrom and you are doing it to lean the boat over so you can send your crew up the mast to fix the spreaders.

Unless you are overpowered, all the telltales should be flying so you would normally adjust controls to achieve that. This was the value of the vang and why I experimented so much with that. When overpowered, you definitely want the top to twist off, and the lug rig does that very well as it pivots around the attachment point. The problem is that if the yard is very bendy, there is a double whammy and excessive twist off results. For cruising off shore this is fine as it provides a lot of comfort and safety. However if you are chasing Lasers around a course and trying to be more competitive, you'll want to limit this twist and have more control over it.

It's a different story when running by the lee in a good breeze. With the flow reversed in a fresh breeze you are watching for the leech to flick. If you have plenty of twist you are quite safe from the boom making a sudden excursion across to the other side. When it's a bit lighter, you can carry more tension in the leech and have less twist. This encourages the sail to "pump" itself, which is fast.

Incidentally, seeing as I mentioned running, I should just mention that it is never a good idea to run with the wind directly from behind because the flow across the sail will be constantly changing direction and the boat can become quite unstable. With the wind coming from either quarter, the boat settles down and becomes predictable. If by the lee and you are still getting a bit of rocking, put 2/3 board down and sheet in a bit more.

As for controlling twist, seeing as you guys are carrying that boom restrictor from the mast to the front of the boom, I'd look at moving the downhaul attachment back a bit to increase the vang effect. To restrict twist when going upwind in light to medium winds, make sure the traveler is tight so the blocks are at the corner and then sheet in a bit harder. If the mast bends a bit you are doing it right!