Thread: GIS Yawl

No jerk taken at all, Paulie. It's detective work.

Clint and I were close hauled to get around Hancock point, but we were able to make it in one tack. Clint barely made it around the point and I was pinching the whole time to make sure I had the sea-way around the point. Then we came around the corner and Clint and I let the sails out a bit as the wind came around, but I can't remember it coming from aft at all. I turned around to go back to Capn Jon after we sailed and was running before the wind to get back to him.

We need videos.

All in all I don't think any of this matters. I am interested in the twist. In this picture

http://1.bp.blogspot.com/-sa9gyjV4el...581ddb8_b.jpeg

which was taken about the same time as the one on page 29, you can see there is less twist from this perspective than from the side.

What is interesting is Clint and I couldn't figure out how come we couldn't catch you with your sail all out, and Clint even yelled over that your sail was out, but when I let mine out to experiment I lost all sorts of speed so I sheeted back in.

Hmmmmmm

Maybe that's the twist? Maybe if I got the twist under control I would have been off like a rocket? From the helm (my perspective) it doesn't look like there is much twist at all. I wonder if maybe I'm just used to it? Maybe my limited traveler adds to the twist? The limited traveler also helps me point higher too though.

Now HERE'S some twist:

http://www.duckworksbbs.com/plans/jim/laguna/gordo.jpg

Mik needs to visit and sort this all out.

And Bruce.

But no racing Bruce. I'm done with racing.

One more: So what's it take, more downhaul to take care of the twist? Additionally, if I did get rid of the twist, I would have had to reef, I was on the edge of it as it was. As mentioned, I don't know if I want to get rid of it!


Also, what is a boom limiter? I don't think I have one. I have a square lashing around the mast, but that usually hangs there limp and works when I'm downwind and the boom is pulling away, otherwise the downhaul keeps it in.

Here's another picture of Clint's twist. Acceptable twist, or unacceptable?

http://3.bp.blogspot.com/-9fhe3p628J...0/DSC00133.JPG

Haha, OK no racing, just sail trim.

Essentially, no twist = power and twist = depower, so there are times to have either condition which of course you already know.

Basic sail trim is simply about removing the leading edge separation bubble. Mick has already referred to the Arvel Gentry articles and the use of tell tales to detect these bubbles. He also discusses where to install these, so my recommendation is to read his articles. Simply trim to get the tufts streaming together whenever possible. So, from a point when the sail is flapping, as you sheet in the sail, you can see the bubble on the leeward side moving forward. The point at which the bubble just disappears from the luff is your correct trim.

If you cannot control the twist much, then the lower 1/3 to 1/2 of the sail is more important than the upper part of the sail as this is where the most power is being generated.

Haha sail trim! I love it. Yes exactly, we're not talking about racing, we're talking about being efficient.

The only reason I didn't install telltales on my sail (I've used them extensively in the 420/FJ/Laser/etc.) is that there is no way I can see through my sail and see the lee side and what the telltale is doing on the opposite side. Maybe if the sun is on the sail from behind, but that's a maybe. I've fooled around at my house and didn't have success. Otherwise I would have added some cotton telltales years ago. My sail is all thick and tough and godawful bright and not see through enough for tell tales.

I will try again though, since it's been baking in the sun enough. Maybe it's starting to break down.

Originally Posted by callsign222

No jerk taken at all, Paulie. It's detective work.

And I was trying so hard to be obnoxious! I guess I'll have to try harder next time.

As for "how much twist is too much", I think it depends on what you are looking to do. That was the point I was trying to make in my post.

Every time I look at those pictures, I'm struck by how far out Clint is hiking. Based on his height, I'm guessing he must weigh over 200lbs. And he's way out over the rail. Yet BLEAT is heeling, with the lee chine dug in.

Where is all that lateral force coming from? Don't say crew placement. Ellie's skinny cousin couldn't tip the boat like that no matter where she sat.

I'm convinced that lateral force is from having the lower part of the mainsail oversheeted.

With the twist in the sail, the upper part is set properly to drive the boat. The lower part is stalled, at least a bit, exerting more lateral force than driving force.

Is this "right"? It depends on what you want. I think you hit the nail on the head, that if you used more downhaul and sheeted out you'd be off like a rocket. But that lateral force is acting as a stabilizer, both directly and, by allowing you to distribute your mass outboard, thereby lowering the resonant frequency of the boat, indirectly. So you'd have a lot less stability. Clint and crew could probably distribute themselves so that BLEAT stayed upright. You, being alone and so light, maybe not.

Keeping the boat up on the chine also allowed your boats to cut through the chop more cleanly. Maybe not an issue on this tack, but it could make a difference going upwind. We saw that on the homeward leg the first day, when a little heel smoothed the ride.

I think the idea is to adjust the twist to get the proper balance of speed, stability, and heel for the conditions. And sometimes you have to sacrifice a little speed for safety.

Originally Posted by callsign222

Also, what is a boom limiter? I don't think I have one. I have a square lashing around the mast, but that usually hangs there limp and works when I'm downwind and the boom is pulling away, otherwise the downhaul keeps it in.

Well, I installed a "boom limiter" today. It attaches the front of the boom to an eye I have installed on the deck in front of the mast. By the way, is this Paulie's invention?

I have also removed the vang and reinstalled my downhaul so that my boat is like a standard GIS once more. Have also moved the downhaul back so that it is about 10cm behind the mast. This is possible because the boom is restrained from moving forward. It may bind a bit on port tack, but we'll see next week when I take it for a blat.

There was 15 kts on my driveway, so went for a sail on the hard. This "boom limiter" thing seems to work and it DOES appear to hold the boom in to the mast, although it's not as close as I'd like so for now will keep the boom to the mast with the usual square lashing as well.

Aaaahh I see. That is somewhat reminiscent of my first downhaul set up

http://2.bp.blogspot.com/_veIyanfT-P...0/P6120437.JPG



which I got rid of soon after my maiden voyage. Interesting idea when it's not included in the downhaul.

Note green plastic cup-- I'm already trashing the boat on it's first sail-- somethings never change.

Bruce -

Thanks. You answered my question about how far aft you moved the downhaul before I asked!

Next question is, by moving the downhaul aft, does it work as effective as a downhaul to tighten the luff?

Originally Posted by woodeneye

By the way, is this Paulie's invention?

Don't know if Joost invented the idea but he uses it and (if I remember correctly) first described it here on the forum.

Originally Posted by woodeneye

Well, I installed a "boom limiter" today. It attaches the front of the boom to an eye I have installed on the deck in front of the mast. By the way, is this Paulie's invention?

Not me! Credit Joost for that. Although we both have something which goes around the mast and slides up and down. Nothing attached to the forward seat.

Originally Posted by callsign222

Note green plastic cup-- I'm already trashing the boat on it's first sail-- somethings never change.

"Green Solo cup, I fill you up. Let's have a party...." That sounds kinda familiar.

Originally Posted by callsign222

Haha sail trim! I love it. Yes exactly, we're not talking about racing, we're talking about being efficient.

The only reason I didn't install telltales on my sail (I've used them extensively in the 420/FJ/Laser/etc.) is that there is no way I can see through my sail and see the lee side and what the telltale is doing on the opposite side. Maybe if the sun is on the sail from behind, but that's a maybe. I've fooled around at my house and didn't have success. Otherwise I would have added some cotton telltales years ago. My sail is all thick and tough and godawful bright and not see through enough for tell tales.

I will try again though, since it's been baking in the sun enough. Maybe it's starting to break down.

That's why I like leach ribbons more than tufts ... you can always see them except for when the rain sticks them to the sail. Combine with watching carefully for luffing at the leading edge of the sail and the groove is much narrower than just looking for luffing.

ie it provides a warning you are sailing too deep or have the sail oversheeted.

MIK