Thread: GIS Yawl

As they say, everything is bigger in Texas, even flat water!

Thanks a million for the rapid and thorough reply. You know I'm asking about the mast step because I'm trying to do less work. Not out of laziness though; I'm afraid I might get sucked down a rabbit hole instead of progressing forward toward launch.

I actually might postpone much of the yawl-ness until after launching, but I've got to install the steps and partners at least while I can do it easily.

Are you posting about your new build?


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Howdy,

That photo makes it look a bit epic!

I guess it was - there was a lot of wind. We quickly found we could sail with very reduced sail without losing much speed at all.

The textbook says pull the mizzen tight so the bow points up into the wind.

This is wrong advice. Because the options are much greater than this.

John was busy with handling the mast end ... we were in the intracoastal waterway. Wind was blowing at about 45 degrees to the channel ... with mudbanks on the lee side and islands and sandbars on the windward side.

With the mizzen pulled in hard the boat pointed nose to wind and went backwards towards the leeward side very quickly. We would have grounded in a minute if that had happened.

However by easing the mizzen the bow falls off and the mizzen partly fills as shown here.

The more you ease the mizzen the more forward pace the boat has.

I was sitting there to balance the boat and I was trimming hte mizzen to establish a sideways drift that was as close as I could get to parallel to the windward edge of the channel. That way we had deep water (though the shallows intensified the chop) under the boat without the additional complication of hitting bottom.

So I was doing little adjusts of the mizzen to move a bit more backwards (pull sheet in) or a bit more forwards (ease sheet out) to keep us in a safe place in the channel.

The speed is not about power .. but about where the trim of the sail allows the bow to point.

It was interesting!

MIK

The way I have gone is to modify the daggerboard slot so I can angle the daggerboard further back when I have the mizzen in place, I'm hoping getting the COE of the daggerboard 6 or so inches further back will have the same effect on restoring balance as moving the main mast forward by 8 or so inches. It seemed an easier and lighter mod than attacking that forward buoyancy compartment to add the second mast step.

I haven't tried this variation on the yawl setup yet - I have my mizzen mast and mizzen mast step ready to go, was going to order the mizzen sail when some extra bills came in, so have to put off buying it for a bit. I may knock up a polytarp mizzen in the next while and see how that goes in the meantime, get a nice tanbark one to match the main made in the spring.

Once the Easter school holidays end, I'm hoping to get out a bit more - I'll have two of three kids at school and should be able to get a few winter mornings out on the lake. It'll be wetsuit, gloves and balaclava sailing, especially if it's blowwing hard, I'll try and post with pictures when I can. I have a waterproof camera now as I drowned the last one

Ian

I'm interested in how your mod to the case will go with the mizzen in place. Ideally you should make another narrower daggerboard as angling the board back some more makes it wider in terms of the flow over it, but I'm splitting hairs as in that mode you are cruising anyway. Keep us posted as to how it goes and helm influences etc.

If we get a good forecast next w/e, I'll start taking the GIS out as the Laser season has closed now. Can't wait to do some nice relaxing sailing for a change!

Hi Bruce, good to hear from you again, and good to hear you are keeping the GIS!

Congratulations on the Laser results.

I'll see how the boat goes in yawl configuration with the current centreboard angled back and the mainsail luff a bit further forward of the mast. I do have it in mind that a longer, narrower centreboard will angle back more and get the underwater COE further back if necessary. It may not be necessary as I think the stiffer spars and loose footed main brings the draft and sail COE further forward when you crank hard on the downhaul in stronger winds.

As you say, I won't be racing in this configuration, but it will be important to get the balance right as conditions get more challenging, there's nothing the only thing worse than fighting a stalled rudder due to too much weather helm is lots of lee helm in stronger wind conditions.

I've decided to make a white polytarp mizzen in the meantime, come up with the $ for a proper one in the spring. That matching tanbark cloth doesn't come cheap...

Ian

I think the best result will be to properly locate the mast step fwd for the lug when the boat is flying the mizzen. Because the mast is not raked much, we don't have the option of raking the mast fwd to adjust CE. The mizzen is small, so the difference will be small between a boat properly adjusted and one not adjusted. I think John Goodman experimented and found the boat handled better with the lug stepped fwd when flying the mizzen. I remember, because I thought "phew" it was all worth it!

Originally Posted by Boatmik

.

The textbook says pull the mizzen tight so the bow points up into the wind.

This is wrong advice. Because the options are much greater than this.

John was busy with handling the mast end ... we were in the intracoastal waterway. Wind was blowing at about 45 degrees to the channel ... with mudbanks on the lee side and islands and sandbars on the windward side.

With the mizzen pulled in hard the boat pointed nose to wind and went backwards towards the leeward side very quickly. We would have grounded in a minute if that had happened.

However by easing the mizzen the bow falls off and the mizzen partly fills as shown here.

The more you ease the mizzen the more forward pace the boat has.

I was sitting there to balance the boat and I was trimming hte mizzen to establish a sideways drift that was as close as I could get to parallel to the windward edge of the channel. That way we had deep water (though the shallows intensified the chop) under the boat without the additional complication of hitting bottom.

So I was doing little adjusts of the mizzen to move a bit more backwards (pull sheet in) or a bit more forwards (ease sheet out) to keep us in a safe place in the channel.

The speed is not about power .. but about where the trim of the sail allows the bow to point.

It was interesting!

MIK

MIK this is great stuff. It really demonstrates the usefulness of a mizz when used right. Essentially you were heaving to, correct?

Originally Posted by CCBB

MIK this is great stuff. It really demonstrates the usefulness of a mizz when used right. Essentially you were heaving to, correct?

Used to mizzen to enter a downwind harbor and dock. Dropped the main outside then sailed in under the mizzen right up to the dock going downwind. Pushed the sprit over hard (clew was facing into the boat) to spill the wind and drifted right to the dock. The mizzen is a handy tool for docking.

Another great example, John.

More: backing off a dock or a beach. I remember my first time watching a skilled yawl sailor back off a crowed beach with his mizzen at the Small Reach Regatta. As the lug went up the mizzen brought the bow around, the lug filled and they shot off.

Jaw dropped, I was immediately a convert.

Originally Posted by john goodman

...Pushed the sprit over hard (clew was facing into the boat) to spill the wind and drifted right to the dock. The mizzen is a handy tool for docking.

Originally Posted by CCBB

More: backing off a dock or a beach. I remember my first time watching a skilled yawl sailor back off a crowed beach with his mizzen at the Small Reach Regatta. As the lug went up the mizzen brought the bow around, the lug filled and they shot off.

Do these techniques depend on the mast rotating around with the boom? Or is there enough give in the sail/snotter tension to allow for a fixed square mast?

I'll be cutting steps and partners soon.

Originally Posted by davlafont

Do these techniques depend on the mast rotating around with the boom? Or is there enough give in the sail/snotter tension to allow for a fixed square mast?

I'll be cutting steps and partners soon.

It's the tension in the snotter that allows for the sail rotation. The mast does not rotate. I had my snotter loose with just enough tension to pull the wrinkles in the leech tight but not bend the tip of the mizzen mast. That keeps a lot of fullness in the luff just behind the mast. When the wind fills the sail will have a good full shape.

Some of the other sailors here in Texas have square masts and they wrap the areas that the yards/sprits rub against the mast with heavy twine. This keeps the square edges from wearing quickly. They also recommend putting on a coat of epoxy or a few coats of varnish to help hold the twine in place. I did this on my oars. I have leather chafe gear on my boom and yard, but not the mizzen.

In the attached picture you can see how loose the snotter is, as the sprit is hanging well below the snotter. If tightened enough to prebend the mizzen mast and flatten the sail, the sail will try to center itself over the rudder. You can still steer the boat with the mizzen. This can be seen the this video. [ame=http://www.youtube.com/watch?v=VHSiWa5QdoU]GIS backing up with mizzen - YouTube[/ame]

JDG

Thanks for the insight. I guess it makes sense that the snotter is not so tight on a mizzen since you're not trying to shape the draft or anything. I think I'm reaching a decision to plan for a square mizzen mast as I install the aft step and partner.

Meanwhile, you sly dog you, is that the GIS North American Championship Burgee I see flying in this pic?

Originally Posted by davlafont

Thanks for the insight. I guess it makes sense that the snotter is not so tight on a mizzen since you're not trying to shape the draft or anything. I think I'm reaching a decision to plan for a square mizzen mast as I install the aft step and partner.

Meanwhile, you sly dog you, is that the GIS North American Championship Burgee I see flying in this pic?

Yes it is the GIS North American Championship Burgee! The other is from the 2011 Sail Oklahoma Messabout held at Lake Eufaula, Oklahoma. Great fun!

Hello all,
Yesterday I took my GIS out for her maiden voyage on the gulf coast of Florida near Crystal River. Yeehaw!
The boat is not finished yet, but I decided to sail it anyway to get a feel for it and work out rigging details.
After checking out and rejecting several launch sites we drove to the village of Ozello which has a lovely sheltered ramp leading to a maze of mangrove islands and oyster beds.
I have to say this boat is gratifyingly easy to sail and I can't wait to get it out in more open water.
But during the course of the outing I came up with a question concerning the mainmast length. At 4730 mm it is ~120 too long to fit inside the boat. This makes stowing the mast for travel a bit complicated; more importantly it makes rowing the boat awkward. So I'm curious how the rig would be affected by shortening the mast just enough to drop inside the hull.
Could the hanging point on the yard be moved forward to compensate without altering the set and balance of the rig?