Thread: GIS sail tweaking

I've got photos of my throat/yard attachment...but computer needs recharging... (not as glamorous as Christophe's working but it'll have to do until later)

Originally Posted by Boatmik

Is the photo yours Clint?
MIK

Taken by my father in law, Fred Osborn, father of Ellie and skipper of the Boston Whaler from which the photo was shot. I have the full size photo and it may be worth looking at several cropped options in case this one is too grainy when blown up.

Photo of the throat/yard attachment used on Karen Ann:



DSCF4779 by bob.wessel, on Flickr

The throat is shackled to the padeye which is through bolted to the yard. The shackle actually rotates 90° from what is shown in the photo when the sail is raised. (not exactly a crystal clear explanation of what the photo shows but ask if it doesn't make sense)

Does the gap between the sail and yard open out at that corner under sailing loads?

Looks like a little lashing through eye and around yard might help make sure that you get all the depth designed into the sail if a gap does appear.

MIK

Originally Posted by BobWes

[/I]The throat is shackled to the padeye which is through bolted to the yard. The shackle actually rotates 90° from what is shown in the photo when the sail is raised. (not exactly a crystal clear explanation of what the photo shows but ask if it doesn't make sense)

Good one Bob!

Here's how I have mine rigged. The line is 4mm dyneema core, the knots are tape knots, (also called water knots). The yard is GIS standard 40mm round.


The red line, and block underneath are not attached to the yard, I was just in a rush, and didn't separate the two for the photo.

Warm beer, that is a perfect example of what doesn't work. I had mine set up the same way while Bruce would email me to stop my silliness. That lashing that goes forward will provide resistance on the the outhaul along the yard, but it will do nothing once you apply the downhaul. The lashing if anything has to go backwards in the direction of the peak to keep the throat from pulling forward so downhaul tension doesn't transition along the head. Once the rig is tensioned, the only line doing anything in this picture is the purple line on the right that wraps around the yard. You need to keep the throat from pulling down.

Tough to explain in words. CCBB might be able to chime in, the lightbulb went off with him when he saw it in action.

Well, dang it, quit your job, go home and take a picture of how you have yours rigged! Kidding aside, I understand now that you put it that way.

If I keep my same yard for now, then I should reposition the throat grommet opposite the yard hole, and lash tight, or shackle it.

Thanks!!!

I wonder if the DF I have in mind for my new boom will work just as well for a new yard. Hmmm

Christophe, as you've had a chance to sail with the throat restrained both ways, what differences in performance and/or sail shape did you notice after making the change?

One night after sailing, the Goat Brothers were down at the waterfront. Christophe was helping me reattach my lower gudgeon. Then we played with the rig. We put mine up. I tensioned the downhaul and as I looked up at the throat and alternated between tension and no tension, I could see the lashing around the yard, sliding up and down. The corner lashing would completely go slack when the d'haul was on hard, then retighten when off. It took about 0.0237 seconds to see what the next step was to be when I got home. So, I'm thinking about gluing an ash eye on the yard and lashing through it, to avoid any holes.

Originally Posted by warm beer

Christophe, as you've had a chance to sail with the throat restrained both ways, what differences in performance and/or sail shape did you notice after making the change?

The luff stays tight, you can adjust the head along the yard as you wish depending on wind/sailing mission through the lashing on the peak, and the yard picks up, which travels the leach, which picks up the end of the boom, without flattening the sail, especially along the head, which is important is lighter air.

Bruce would probably have a better more technical answer.

I also did it in conjunction with FRANKENBoom, so tough to tell what did what.

Originally Posted by CCBB

One night after sailing, the Goat Brothers were down at the waterfront. Christophe was helping me reattach my lower gudgeon. Then we played with the rig. We put mine up. I tensioned the downhaul and as I looked up at the throat and alternated between tension and no tension, I could see the lashing around the yard, sliding up and down. The corner lashing would completely go slack when the d'haul was on hard, then retighten when off. It took about 0.0237 seconds to see what the next step was to be when I got home. So, I'm thinking about gluing an ash eye on the yard and lashing through it, to avoid any holes.

I have actually been imagining some sliding happening at some places, and I have been considering to glue two small wood pieces on each side of the spar at those places where some sliding might occur. A tight loop around the spar will not be able to get over those wood pieces.

Originally Posted by callsign222

The luff stays tight, you can adjust the head along the yard as you wish depending on wind/sailing mission through the lashing on the peak, and the yard picks up, which travels the leach, which picks up the end of the boom, without flattening the sail, especially along the head, which is important is lighter air.

Bruce would probably have a better more technical answer.

I also did it in conjunction with FRANKENBoom, so tough to tell what did what.

Thanks for the info Christophe and Clint. I am naming my new boom "Bumi", after King Bumi - the earth bending king from the animated Avatar series. I am rotating my yards. My old boom becomes my new yard, as it is thicker, and my new Bumi stock, has been purchased, and is ready for shaping and coating this Friday.

Quick question(s) - when applying epoxy to a long spar, what is the best way to suspend it? Do you try to coat the entire spar in one go (three coats wet on wet) suspended at the ends, or do you coat one side, then give it the pancake flip and coat the other. Remember - I'm a neophyte.

Originally Posted by callsign222

The luff stays tight, you can adjust the head along the yard as you wish depending on wind/sailing mission through the lashing on the peak, and the yard picks up, which travels the leach, which picks up the end of the boom, without flattening the sail, especially along the head, which is important is lighter air.

Bruce would probably have a better more technical answer.

That's about it Christophe!

Originally Posted by warm beer

Quick question(s) - when applying epoxy to a long spar, what is the best way to suspend it? Do you try to coat the entire spar in one go (three coats wet on wet) suspended at the ends, or do you coat one side, then give it the pancake flip and coat the other. Remember - I'm a neophyte.

Why not put a screw in each end and suspend it between a couple of saw horses?