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Are You Loosing Sail Control By Going To A Double Main Sheet System

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Created by Zzzzzz > 9 months ago, 29 Oct 2020
Zzzzzz
513 posts
29 Oct 2020 4:38PM
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Next project coming up is updating the trailer system, as we all know that can be expensive, would I be loosing much in sail control if I ditch the traveler and set up two main sheets from each corner of the boat ? Also is it a pain in the ass using the two main sheet system?
I like the idea of using the offside sheet as a preventer.
Any thoughts please.

BlueMoon
866 posts
30 Oct 2020 4:07AM
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I'll be doing this on my Compass 28, I think you'll be gaining sail control, and keeping the boom firm while mooring is also a bonus

lydia
1927 posts
30 Oct 2020 4:32AM
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You are actually losing sail control as you can not adjust quick enough.
These are small boats so sleve the boom at the vang, double the vang purchase and use a single fixed main sheet take off. And just vang sheet if you'd want to get rid of the traveller
Or go to a rope bridle.

lydia
1927 posts
30 Oct 2020 4:32AM
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You are actually losing sail control as you can not adjust quick enough.
These are small boats so sleve the boom at the vang, double the vang purchase and use a single fixed main sheet take off. And just vang sheet if you'd want to get rid of the traveller
Or go to a rope bridle.

Zzzzzz
513 posts
30 Oct 2020 5:30AM
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lydia said..
You are actually losing sail control as you can not adjust quick enough.
These are small boats so sleve the boom at the vang, double the vang purchase and use a single fixed main sheet take off. And just vang sheet if you'd want to get rid of the traveller
Or go to a rope bridle.


Thank you for your reply Lydia , I have to go to the mast to use the vang do not so quick , please excuse my naivety but does the vang do the same job as the track ?

Ramona
NSW, 7732 posts
30 Oct 2020 8:52AM
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Keep the traveller and install a boom strut or rod kicker. I made my boom strut out of laminated timber and epoxy/fibreglass cloth. Have all the controls back to the cockpit. Boom strut transforms reaching and downwind sailing and makes reefing easier too.

DrogueOne
215 posts
30 Oct 2020 8:40AM
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Zzzzzz said..
Next project coming up is updating the trailer system, as we all know that can be expensive, would I be loosing much in sail control if I ditch the traveler and set up two main sheets from each corner of the boat ? Also is it a pain in the ass using the two main sheet system?
I like the idea of using the offside sheet as a preventer.
Any thoughts please.


Are you thinking about the "german" mainsheet system, where you have a mainsheet tail on each side of the boat? They often still had travelers anyway and relied on big winches to do the grunting in of the sheet as they were only 2:1 purchases. I don't think the offside sheet could be used as a preventer as the sheet is not actually dead-ended on the boom, besides a preventer is useful when you are off the wind where the sheet angle boom-to-corner will not prevent a gybe.

It probably comes down to how you sail, what do you find difficult or awkward about the current set up? Are some components close to failing? Do you use the traveler to play the gusts, set the angle of attack or allow twist in heavy air?

Zzzzzz
513 posts
30 Oct 2020 10:51AM
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DrogueOne said..

Zzzzzz said..
Next project coming up is updating the trailer system, as we all know that can be expensive, would I be loosing much in sail control if I ditch the traveler and set up two main sheets from each corner of the boat ? Also is it a pain in the ass using the two main sheet system?
I like the idea of using the offside sheet as a preventer.
Any thoughts please.



Are you thinking about the "german" mainsheet system, where you have a mainsheet tail on each side of the boat? They often still had travelers anyway and relied on big winches to do the grunting in of the sheet as they were only 2:1 purchases. I don't think the offside sheet could be used as a preventer as the sheet is not actually dead-ended on the boom, besides a preventer is useful when you are off the wind where the sheet angle boom-to-corner will not prevent a gybe.

It probably comes down to how you sail, what do you find difficult or awkward about the current set up? Are some components close to failing? Do you use the traveler to play the gusts, set the angle of attack or allow twist in heavy air?


Hi Drogueone the old track is missing bits and I really like to use it to power and depower the main as we all do.
so was doing some research on it came across a video on the two main sheet idea , playing it around the mind to see if it will do the same as the track

shaggybaxter
QLD, 2647 posts
30 Oct 2020 12:52PM
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Zzzzzz said..





lydia said..
You are actually losing sail control as you can not adjust quick enough.
These are small boats so sleve the boom at the vang, double the vang purchase and use a single fixed main sheet take off. And just vang sheet if you'd want to get rid of the traveller
Or go to a rope bridle.







Thank you for your reply Lydia , I have to go to the mast to use the vang do not so quick , please excuse my naivety but does the vang do the same job as the track ?






Hiya Zzzz,
Vang sheeting is more relevant when you have no/limited traveller.
The vang, like your mainsheet, sets the mainsail twist and leach tension.
Say you have no traveller and you bear off a close hauled course and crack sheets. As you ease your mainsheet to orient your sailplan to the new wind direction (keeping the airflow attached to the back of your mainsail) the boom will lift, leach tension decreases and the top of the main twists off, robbing you of power.
But by sheeting on the vang before you ease the mainsheet, the boom cannot lift, leach tension is maintained and the top of the sail is tight and drawing.

Ergo, by vang sheeting your mainsheet replaces the traveller, and the vang replaces the mainsheet.

As the vang connects to the boom much further forward than your mainsheet, the loads are nearly double, hence why you sleeve a weak boom and use big blocks if you intend to use vang sheeting.

Edit: if you are vang sheeting, you need the control line in the cockpit on a winch (loads are higher than your mainsheet). It would be very difficult to use effectively if you have to run to the mast to control.

Cheers,
SB

Zzzzzz
513 posts
30 Oct 2020 11:03AM
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shaggybaxter said..

Zzzzzz said..





lydia said..
You are actually losing sail control as you can not adjust quick enough.
These are small boats so sleve the boom at the vang, double the vang purchase and use a single fixed main sheet take off. And just vang sheet if you'd want to get rid of the traveller
Or go to a rope bridle.







Thank you for your reply Lydia , I have to go to the mast to use the vang do not so quick , please excuse my naivety but does the vang do the same job as the track ?






Hiya Zzzz,
Vang sheeting is more relevant when you have no/limited traveller.
The vang, like your mainsheet, sets the mainsail twist and leach tension.
Say you have no traveller and you bear off a close hauled course and crack sheets. As you ease your mainsheet to orient your sailplan to the new wind direction (keeping the airflow attached to the back of your mainsail) the boom will lift, leach tension decreases and the top of the main twists off, robbing you of power.
But by sheeting on the vang before you ease the mainsheet, the boom cannot lift, leach tension is maintained and the top of the sail is tight and drawing.

Ergo, by vang sheeting your mainsheet replaces the traveller, and the vang replaces the mainsheet.

As the vang connects to the boom much further forward than your mainsheet, the loads are nearly double, hence why you sleeve a weak boom and use big blocks if you intend to use vang sheeting.

Cheers,
SB


Gee Shaggy thanks for the in-depth reply that will explain why my boom broke in half many years ago while using the vang as a preventor I had the dinghy tied on the roof and the Pardies said they use theirs that way .
it soon had a sleeve over the boom , much appreciated

shaggybaxter
QLD, 2647 posts
30 Oct 2020 1:24PM
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Zzzzzz said..

shaggybaxter said..


Zzzzzz said..






lydia said..
You are actually losing sail control as you can not adjust quick enough.
These are small boats so sleve the boom at the vang, double the vang purchase and use a single fixed main sheet take off. And just vang sheet if you'd want to get rid of the traveller
Or go to a rope bridle.








Thank you for your reply Lydia , I have to go to the mast to use the vang do not so quick , please excuse my naivety but does the vang do the same job as the track ?







Hiya Zzzz,
Vang sheeting is more relevant when you have no/limited traveller.
The vang, like your mainsheet, sets the mainsail twist and leach tension.
Say you have no traveller and you bear off a close hauled course and crack sheets. As you ease your mainsheet to orient your sailplan to the new wind direction (keeping the airflow attached to the back of your mainsail) the boom will lift, leach tension decreases and the top of the main twists off, robbing you of power.
But by sheeting on the vang before you ease the mainsheet, the boom cannot lift, leach tension is maintained and the top of the sail is tight and drawing.

Ergo, by vang sheeting your mainsheet replaces the traveller, and the vang replaces the mainsheet.

As the vang connects to the boom much further forward than your mainsheet, the loads are nearly double, hence why you sleeve a weak boom and use big blocks if you intend to use vang sheeting.

Cheers,
SB



Gee Shaggy thanks for the in-depth reply that will explain why my boom broke in half many years ago while using the vang as a preventor I had the dinghy tied on the roof and the Pardies said they use theirs that way .
it soon had a sleeve over the boom , much appreciated


One thing I forgot Zzzz,
How soft or whippy your mast is needs to be thought about too. More vang tension means more bend in a whippy mast, which flattens and depowers the main. If you have no vang tension with a bendy mast, it stands up more, allowing more curve or draft in the main, which is a more powerful shape.
So with a whippy mast, by sheeting on the vang to maintain power by keeping the boom low and leach tension tight, you can also rob power as your are flattening the main as the mast bends.
Gotta love boats :) !

DrogueOne
215 posts
30 Oct 2020 11:50AM
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Nice explanation Shaggy,
Interesting how dinghy techniques have over the years moved up scale. Bendy boom also robs power with vang sheeting.
Lydia's suggestion about rope bridle is another dingy technique that is pretty effective in getting the boom on the centreline for upwind work but doesn't give you much in the way of gust control or boom positioning when overpowered. Contenders/420 mid-boom bridles would have clips so you could use a short bridle for normal conditions and a longer one when it was a bit overpowered and you wanted to let the boom lift a bit. Stern mounted bridles like the 49er again good for positioning but I think rely on crew competence and feathering/easing when overpowered.

I'm thinking though the traveler advantages give you a lot of control in both light and strong wind conditions without having to tweak multiple controls to get the same effect. embrace the $$ pain.



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"Are You Loosing Sail Control By Going To A Double Main Sheet System" started by Zzzzzz