Mainsheet Vs. Traveler

[scarlet]

Our little boat only has a mainsheet, and no traveler. So, I only know how to adjust the mainsheet. I have sailed on boats that have travelers but other people have either adjusted them without instruction, or didn't use them at all.

Next week I'm chartering a boat that has both, and I've been reading about, and watching videos to try to learn what each one does so that I can practice a little more advanced sail trim than I can on my little 22'.

I feel like a complete idiot because I still don't "get it".

Yes, I understand that the traveler sets the angle to the wind, and the mainsheet adjusts twist. However, in the videos that I've watched it appears that they both make the same adjustment. If you move the traveler the boom moves and changes the angle to the wind. Makes sense. If you move the mainsheet, the boom also moves... um... and also changes the angle to the wind? In both cases, you are adjusting a sheet, and the boom is moving either in or outwards. If they both make the same adjustment to the boom, how is it that they affect 2 different things?

Also, I have read 2 completely conflicting tidbits of advice. Half of what I've read states that you should set the twist first (mainsheet) and then the angle of attack (the traveler). The other half of the articles I've read advise to do it just the opposite. What do you do?

[jt11791]

The main sheet does more than move the boom from side to side, it also pulls the boom down. The traveler only moves the boom from side to side. Thus, easing the main sheet lets the boom rise and increases the twist in the sail, while also changing the angle of attack. Moving the traveler changes only the angle of attack.


Does that help?

[Dockhead]

By the way, there's more to leech tension than just twist. This also determines the shape of the sail in the vertical dimension, complementing the outhaul.



As the previous poster said -- the main sheet is a complicated control which pulls down vertically, determining leech tension (and thus shape and twist), and also pulls the boom up athwartships, changing the angle of attack. So it is controlling three things at once, in one or another messy combination: angle of attack, shape, and twist. The further out the boom is, the greater the athwartship component compared to the vertical component.



The traveler by way of contrast is a very pure control which does nothing but angle of attack. It's a godsend when trying to get the mainsail working right, and I don't know how anyone sails without one.


The normal procedure is to get the sail in the shape you need (including twist) with mainsheet and outhaul, then use the traveler to set the right angle of attack.



If you need more angle of attack than the traveler can deliver, then set the vang and let the mainsheet out. At a certain point, leech tension is all in the hands of the vang, and the mainsheet becomes a pure angle of attack control -- a blessed moment. Don't forget the preventer.

[jt11791]

To answer the second part of your question, I set the main sail shape (twist, etc.) first, then angle of attack (AoA). AoA is something that you may wish to change frequently in gusty conditions, whereas sail shape is a function of the average wind speed. While racing on a beat, we continually adjust the traveler for puffs and waves, but generally don't change the main sheet.

[NakedCity]

Whether you do this or that in whatever order makes no difference what so ever. You need to be able to look at your mainsail and understand the shape you need for the conditions and your point of sail.
As a general assumption if you what to go to weather in not overpowered conditions you will want your boom on the centerline and no twist in the leech. To achieve this your mainsheet will be pulled hard, and the traveller will have to be positioned above the centerline in order for your boom to be on centerline.
As you crack off onto a close reach you will want to lower the traveller and ease the sheet. The more you bear away the more your traveller and sheet need to be eased. After your boom has been eased beyond your traveller you can no longer control twist with the sheet because you can no longer exert downward pressure on the boom. At this point your vang must take over the twist control and the sheet becomes strictly your angle of attack control.Without the vang you will be spilling all your power out of the top of the sail, because there will be no downward pressue on the boom, the wind puffs, the boom will lift, the top of the sail twists off and spills all your power.

Don't get discouraged, it took me about 20 years for the lightbulb to go off and be able to look at a sail and know what it needed to be more efficient.

[psk125]

If you're confused, simply start by setting the traveler on the centerline. The main sheet will work just like you're used to on your boat. If you head off on a reach or dead downwind,however, you'll find that easing the traveler out makes sense so that the sail doesn't twist off so much on those points of sail. Don't overthink it or worry about it - you're on vacation!

[scarlet]

Originally Posted by jt11791

To answer the second part of your question, I set the main sail shape (twist, etc.) first, then angle of attack (AoA). AoA is something that you may wish to change frequently in gusty conditions, whereas sail shape is a function of the average wind speed. While racing on a beat, we continually adjust the traveler for puffs and waves, but generally don't change the main sheet.

So, an additional clarifying question. How far off the wind do you need to go (after raising the main into the wind) in order to set the twist? Do you turn the boat to your heading first, then set the twist? For example:

If you were going from into the wind as you raise your mainsail to a beam reach, do you:

(a) let the mainsail out as your turn? (which is what I do on my boat)
(b) or do you ease the mainsheet immediately to set the twist (you can't do that if you are pointed into the wind, so I assume you would have to bear off to at least a close haul)
(c) Or, do you bear fully off the wind until you reach your heading (say a beam reach) then start to easing the mainsheet to set the twist? I'm guessing that would work, but I would think the jib would have to be trimmed well first, right?

btw... i think I'm understanding better. It seems like this is all basic sail trim, but like I said originally, we don't have a traveler, so I've never worked with one...

[Dockhead]

Originally Posted by psk125

If you're confused, simply start by setting the traveler on the centerline. The main sheet will work just like you're used to on your boat. If you head off on a reach or dead downwind,however, you'll find that easing the traveler out makes sense so that the sail doesn't twist off so much on those points of sail. Don't overthink it or worry about it - you're on vacation!

That's an excellent suggestion!


Then after you've got the sails set up the way you are used to doing it, enjoy being able to change the angle of attack of the sail without messing up the shape and twist you've taken so much trouble to set with the sheet, vang, and outhaul


To the OP: It's harmful to think of shape just in terms of twist. Twist is just one aspect of changing leech tension. The other aspect is the fullness or flatness of the sail, when leech tension is adjusted in partnership with foot tension via the outhaul. Draft position is also affected. Twist appears when the leech is not tight enough to maintain a uniform curve, and is far from the main thing going on when you play with leech tension.


Just remember this: Pull the boom DOWN, and increase leech tension. Pull the boom OVER, and change the angle of attack -- the angle the sail makes to the wind. The mainsheet pulls only DOWN when the boom is over the traveler car. As you let it out from there, it keeps pulling DOWN, but less and less, and more and more it's pulling OVER, the more it goes out. Got it?


So use the traveler instead of the sheet to move the boom OVER when you need to change the angle of attack. As you do so, the shape will stay the same. Once you need an angle which goes beyond the end of the traveler, then set the vang and use that for pulling the boom DOWN -- then the sheet becomes a control purely for pulling the boom OVER, and starts to work like the traveler did before..




I like to set the vang on a little even when the boom is over the traveler -- so that it acts as a limit on the boom's rising, so that the boom will stay at a more or less constant height as I start to let the sheet out. That makes it easier to control angle of attack with the sheet without messing up the shape of the sail, even when the boom is still over the traveler.

[Tornadosailing]

Here are a couple of things to read about catamaran sail trim. The traveler and mainsheet relationship is a little different on a cat than a mono. Even then, it's a little different from boat to boat. I've raced boats where you set the twist with the mainsheet, and play the traveler. On my Hobie 33 I set the traveler and play the mainsheet.

In the Cruising world article they put it very simply. "On a catamaran, it's all about the traveler".

https://outchasingstars.com/2014/08/...ing-catamaran/

https://www.cruisingworld.com/how/tr...ts-mighty-main

https://youtu.be/LVcVGZdLImE

[Suijin]

I usually trim main when racing and on boats that are very sensitive to main trim. There is a saying that “the main steers the boat” and on any performance boat that is true...and you steer with the traveler, particularly when beating to windward.

Point the boat where you want to go, adjust halyard, cunningham, outhaul and mainsheet to get the desired sail shape for conditions (a whole other topic), THEN use the traveler to balance the boat, keep her on her feet through puffs and lulls, to control weather helm. It’s like another tiller, and it’s why on race boats the helmsman and main trimmer sit side by side and natter at each other constantly.

[scarlet]

Originally Posted by Tornadosailing

Here are a couple of things to read about catamaran sail trim. The traveler and mainsheet relationship is a little different on a cat than a mono. Even then, it's a little different from boat to boat. I've raced boats where you set the twist with the mainsheet, and play the traveler. On my Hobie 33 I set the traveler and play the mainsheet.

In the Cruising world article they put it very simply. "On a catamaran, it's all about the traveler".

https://outchasingstars.com/2014/08/...ing-catamaran/

https://www.cruisingworld.com/how/tr...ts-mighty-main

https://youtu.be/LVcVGZdLImE

thank you.. these were all good. the video particularly.