Observation

[Stu Jackson]

I am presuming that we want the boom to stay where it is so both the traveler and the sheet must be adjusted, don't they?

Nope. You want to the boom to move.

Dan, Don's book is great in explaining this stuff. You should buy it.

The mainsheet controls the draft, the traveler does the angle of attack. Two separate things.

You can depower with the traveler by dropping it. This will backwind the main some.

If you let out the mainsheet the body of the sail gets deeper making it more powerful, just when you want less power.

Also, do a Google search or search here for "fisherman's reef."

 

[Daveinet]

lowering the traveler to lower the Angle of Attack (AOA) of the main leaves it in general trim but depowers it. ...

Hmm, I always thought that moving the traveler leeward raised the point of twist, till eventually there is no twist at all. Moving the traveler to windward should lower the point of twist, which would mean you are spilling more wind off the top of your sail. (or if set correctly compensates for wind shear). I would assume that the flattening occurs after you get rid of all twist, as when you pull down on the boom, you pull some of the belly out of the lower part of the sail. It seems like only after you lower the point of twist substantially that the boom rises enough to put a lot of belly in the sail, that the sail will power up for light winds.
In some ways, this seem counter productive, as if you have more wind, you want to induce twist, however inducing twist seems to also increase draft as the boom rises. In light winds, one would have less wind shear, so having less twist and lots of draft would be desirable. Seems like it is hard to get both.

Am I getting this, or am I off on what I'm picturing?

 

[Stu Jackson]

Buy Don's book. Please.

The traveler does not do anything about twist.

 

[Jackdaw]

Hmm, I always thought that moving the traveler leeward raised the point of twist, till eventually there is no twist at all. Moving the traveler to windward should lower the point of twist, which would mean you are spilling more wind off the top of your sail. (or if set correctly compensates for wind shear). I would assume that the flattening occurs after you get rid of all twist, as when you pull down on the boom, you pull some of the belly out of the lower part of the sail. It seems like only after you lower the point of twist substantially that the boom rises enough to put a lot of belly in the sail, that the sail will power up for light winds.
In some ways, this seem counter productive, as if you have more wind, you want to induce twist, however inducing twist seems to also increase draft as the boom rises. In light winds, one would have less wind shear, so having less twist and lots of draft would be desirable. Seems like it is hard to get both.

Am I getting this, or am I off on what I'm picturing?

You and Dan have this completely backwards. Either in your thought process or your terminology.

As long as the vang is off, the MAINSHEET controls twist, easing the mainsheet out, the higher the boom can rise, and more twist.

Pulling (trimming) the mainsheet takes away twist.

But these actions will also affect WHERE the boom is relative to the centerline. You use the traveler to adjust that. On a well trimmed boat, the main trimmer is using both constantly.

Once set, you can ease the traveler to leeward to lower the AOA and depower the sail.

In the picture below, the Blue line is the mainsheet. The black bar at the bottom is the traveler.

 

[Daveinet]

I'm making an assumption that the main sheet is adjusted to keep the boom port to starboard position the same in each case, as that position is primarily optimized for apparent wind. Only the traveler is moved, and the result moves the boom up and down to shape the sail. Leeward lowers the boom, removing twist, windward raises the boom which increases twist (and lowers the point of twist).

Once set, you can ease the traveler to leeward to lower the AOA and depower the sail.

That is where the difference lies in our descriptions. I was speaking purely from a sail shape position, with the boom port to starboard as static, where you are keeping the sail shape static, and changing the boom angle. I was describing the affect on sail shape boom up and down, you were describing sail/boom angle thwartship.

 

[Joe]

Wow.... talk about confusion....

Think of it this way... the purpose of the traveler is to allow you to move the boom in and out without changing the twist (which can also be defined as leech tension).

You can also think of the mainsheet as controlling the VERTICAL level of the boom.. thus leech tension(aka twist) While the traveler would control the HORIZONTAL position (Which is Angle of Attack, AOA)

Twist is necessary to compensate for the difference in wind speed from top to bottom and it's effect on apparent wind angle on the mainsail.... this is called sheer. A minimum of 3 telltales placed along the leech of the mainsail allow us to visualize, then adjust the twist.

Angle of Attack places the sail at the position it needs to ensure flow over both sides which is directly related to the apparent wind angle.

When we start sailing we set our mainsail twist for the general conditions...

Then we use the traveler to adjust the mainsail's angle of attack to match alterations in apparent wind direction caused by boat speed and true wind speed and true wind direction changes.

Okay... now that that is clear... what happens if you bear off on a broad reach and the boom moves out beyond the reach of the traveler? Interestingly enough, the mainsheet now takes over control of the boom's horizontal movement because it's not pulling up and down anymore... and.. the vang can now be used to control the boom's vertical position (twist again)

In practice it works like this. You set your twist first, using the tell tales. This is done by tensioning the mainsheet until the back of the top batten is pointed in the same direction as the boom, center the traveler, then ease the sheet until the tales start flowing. With the twist set you can use only the traveler to set the sail's angle of attack.... the goal is to make minor adjustments with the traveler to compensate for variations in apparent wind direction.... the ultimate goal is to keep the boat flat or on its optimal heel angle.. and thus its optimum speed (in kts, of course)

Let's say you're sailing on your course and the apparent wind angle is 45 deg off the bow. You get hit by a gust of wind... this increase in true windspeed will move the apparent wind angle AFT, say to 55 deg... that puts more pressure on the windward side of the sail and the boat starts heeling.... Instead of dumping air with the mainsheet, destroying the trim... you drop the traveler... the change in angle of attack will match the change in apparent wind and equalize pressure on the sail... the boat will stay on her feet and might even pick up speed... the INCREASE in boat SPEED will move the apparent wind angle forward again... so you adjust the traveler again to match this change... As the gust and windspeed goes back to normal... you change the angle of attack with the traveler but your mainsail twist requires no adjustment... because it's never changed.

When you are steering to a course "playing the traveler" is the preferred method (by me at least). Of course, if you're sailing close hauled it is more effective to steer to the jib telltales.... using the tiller to adjust angle of attack rather than the traveler.

 

[danstanford]

Fantastic explanation Joe, I think we all understood and believed this all along. I, and I think Dave, were working from a place of affecting sail shape by the combination of traveler and main sheet since they are inevitably linked if you accept the premise that in my example I was assuming the boom was staying at the 45 degree angle to the boat which you used. I have enjoyed the discussion and it has reinforced many of the beliefs I held about the use of the traveler in particular.

As it may be getting lost I am going to put my question in a separate post.

Thanks for the cogent response, it summarizes all of the elements in one place.
Dan

 

[danstanford]

In post #27 Pateco asserts that changing the position of the traveler will maintain trim and be a tool to affect weather helm. This I understand and agree with though my boat is so balanced that weather helm has never been much of an issue for me other than in a gust.

My question, seeking a better understanding is based on the rest of Pateco's assertion that this change in weather helm comes about due to changing the place where the force of the sail is being applied to the stern of the boat. If this is simply how he thinks about it I have no problem with that, but I am trying to understand how it would work and that is the root of my question. Jackdaw said it was really well explained which further piqued my interest and prompted another question.

No trolling here, just somebody trying to get a little smarter. Good trim is a huge part of my enjoyment of the whole experience of sailing and I always want to get better.
Thanks, Dan

 

[Jackdaw]

In post #27 Pateco asserts that changing the position of the traveler will maintain trim and be a tool to affect weather helm. This I understand and agree with though my boat is so balanced that weather helm has never been much of an issue for me other than in a gust.

My question, seeking a better understanding is based on the rest of Pateco's assertion that this change in weather helm comes about due to changing the place where the force of the sail is being applied to the stern of the boat. If this is simply how he thinks about it I have no problem with that, but I am trying to understand how it would work and that is the root of my question. Jackdaw said it was really well explained which further piqued my interest and prompted another question.

No trolling here, just somebody trying to get a little smarter. Good trim is a huge part of my enjoyment of the whole experience of sailing and I always want to get better.
Thanks, Dan

A sailboat is 'ballanced' by matching the work the sails do with the work the the underwater appendages (keel+rudder) do. It kind of looks like this.

Ideally the combined COE of the sailplan will be just AFT of the CLR. This will give the boat slight weather helm.

The KEY is that assumes the sails are in ideal trim. Moving them slightly out of ideal trim, like by moving the traveler down an inch or two, will do this and 'balance' the boat.

As noted before, its actually desirable for a boat to have slight weather helm when going upwind.

 

[danstanford]

Great explanation with a good diagram Sir. This fits my understanding and explains the reasons.

I greatly appreciate the time you took to do this,

Dan

 

[Apex]

... I am installing a wind vane this winter as well. Speaking of which, anyone tried the vane that combines with the vhf antenna? We are looking forward to an exciting season next year with new sails, flying ....

Sam in IN

Sam, I was going to try, but the antenna base was below the masthead, so wouldn't work. On that same note, I do then have a brand new windex for antenna for sale.

 

[Joe]

Fantastic explanation Joe, I think we all understood and believed this all along. I, and I think Dave, were working from a place of affecting sail shape by the combination of traveler and main sheet since they are inevitably linked if you accept the premise that in my example I was assuming the boom was staying at the 45 degree angle to the boat which you used. I have enjoyed the discussion and it has reinforced many of the beliefs I held about the use of the traveler in particular.

As it may be getting lost I am going to put my question in a separate post.

Thanks for the cogent response, it summarizes all of the elements in one place.
Dan

Dan.. there's probably something in your premise that I disagree with ....but it's not worth nitpicking. I encourage you to NOT over think this.

The reason so many of us appreciate Don's trim guide is because he keeps is simple, seriously. If you think of the traveler as a tool to position the sail in relation to the apparent wind direction... then you have one less thing to think about.

When the apparent wind moves so far aft that the boom extends beyond the range of the traveler.. the mainsheet takes over angle of attack duties and has little effect on leech tension... instead the vang assumes that responsibility.

 

[Don Guillette]

Joe from San Diego hit the nail when he mentioned "confusion" and "over thinking". Over the years, I've had a million sail trim conversations. The most difficult ones for me are where the sailor starts in the middle, so to speak, instead of letting me explain what the sail trim control they're interested in discussing actually does they go off on a tangent and sometimes I fall into the trap and try to follow them. I understand what they're going through because I was there myself and I hate to see mates go through what I went through to learn how to sail a silly sailboat. Finally, I have to say STOP and LISTEN to me and forget what you're talking/thinking because you're even confusing me. That's what happened when I started following this topic.

I don't care what a person is trying to learn, unless they go about it in a logical manner started with what all the sail trim controls are adjusting, which is draft depth, draft position, twist and angle of attack. They have to completely understand those 4 elements or sail trim will never make any sense. Next, they have to know which main/jib sail trim control adjusts each of those elements and what happens when you push/pull each control. What I'm talking about is pilots ground school or kindergarten for sailors - that's my teaching lot in sail trim life. Once they graduate from my stuff then they advance to college with jackdaw, Joe from San Diego, RichH, Stu, Scott and others. I can't teach at the level of those guys, nor do I want to because I love newbies -- most of them!! You can't go to sail trim college until you graduate from primary school because you won't know what they're talking about.

I've used this example many times to describe the how the traveler works. The traveler is the simplest control to understand. Picture your screen door with a pin in the corner which rides in a grove in the floor. When you open and close your screen door does the shape of the screen door change? Of course it doesn't and you could install a 50' traveler on your boat and the result would be the same - the shape of the mainsail will not change no matter how far you move the traveler. That's why it's a great control to use in a gust. When the gust hits, just drop the traveler and after the gust passes just put it back to it's original position and go merrily on your way. Introduce the mainsheet or other mainsail control in conjunction with the traveler and you get a different result.

I think I'll now have a "tinney -Aussie for beer" and try to clear my brain!!

 

[Daveinet]

Don and others, that is fine, once you've accomplished your initial setup. As a matter of fact, I sometimes will connect a bungee to the traveler to automatically adjust for apparent wind.

During your initial setup, the traveler allows for different sheeting angles for a given boom position - the same as it does on the jib cars.

For all this talk about using the traveler as the primary control for boom position athwartship, I have yet to see a traveler that is actually designed for real time adjustment or even cleated for that matter. Most are set up just like the jib cars, with stopping pins or small lines to permanently set the traveler position. I have yet to see one set up for continual operator adjustment. Mine has locking pins, so my bungee setup is the only practical way to adjust it on the fly. Otherwise you stand a good chance of getting your fingers pinched. Its really not safe to adjust the traveler with much wind load, so you have to use the mainsheet.

 

[Don Guillette]

For all this talk about using the traveler as the primary control for boom position athwartship, I have yet to see a traveler that is actually designed for real time adjustment or even cleated for that matter. Most are set up just like the jib cars, with stopping pins or small lines to permanently set the traveler position. I have yet to see one set up for continual operator adjustment. Mine has locking pins, so my bungee setup is the only practical way to adjust it on the fly. Otherwise you stand a good chance of getting your fingers pinched. Its really not safe to adjust the traveler with much wind load, so you have to use the mainsheet.[/QUOTE]

You should check out the Garhauer Marine travelers or for that matter Harken etc as all modern travelers are set up for continual use under any condition and they are completely safe to use in any wind condition. I've adjusted the Garhauer in 45 knots of wind in Santa Cruz -- 45 knots of wind for those Santa Cruz guys is a light breeze!!

The curved track traveler on my C30 was the first item I replaced with the Garhauer straight track. The curved track was loaded with friction and a bear to deal with. The second item I replaced was pin type fairleads. I installed the Garhauer adjustable fairleads.

 

[Don Guillette]

One last point -- using a bungee for anything other than to tie up a flaked sail is dangerous. I darn near lost an eye to those things -- the end came off and shot across the boat like a rocket and hit me in the forehead. The skipper of the boat I was on was using it as a preventer even though I told him it wasn't a good idea. I wish the damm thing had hit him in the head!!!

 

[Daveinet]

I would not use it as a preventor either. That would be nuts as it could easily be over extended and is at head level. A traveler on the other hand has limited travel, so it will not over extend the bungee. Even if for some reason it did let loose, it is at butt level, so no chance of a serious injury. Yes, I thought that through before making the choice.

 

[Stu Jackson]

Garhauer travelers

For all this talk about using the traveler as the primary control for boom position athwartship, I have yet to see a traveler that is actually designed for real time adjustment or even cleated for that matter. Most are set up just like the jib cars, with stopping pins or small lines to permanently set the traveler position. I have yet to see one set up for continual operator adjustment. Mine has locking pins, so my bungee setup is the only practical way to adjust it on the fly. Otherwise you stand a good chance of getting your fingers pinched. Its really not safe to adjust the traveler with much wind load, so you have to use the mainsheet.

Dave, Don's right. If you have a traveler with a pin setup it is useless, that's why so many folks don't bother with it.

You could look around in your marina, you'll probably see lots of better examples. Newer Catalinas ALL have Garhauer travelers.

Mine is a 6:1 purchase, with the control lines led through bullet holes in my forward dodger "windows" to cam cleats on the cabintop.

They are so easy to adjust.

I use the mainsheet only twice a day: I start out with it tight since that's the way it is setup when we are the dock and we usually sail upwind at the beginning of any given day and downwind only coming home, so: Mainsheet adjustment #1: when starting to go downwind I let it out; Mainsheet adjustment #2: end of day flaking mainsail, tighten it up.

Pretty easy.

All the rest is the use of the traveler. In many cases I can ease the traveler out enough for a beam reach without touching the mainsheet. Sometimes I do.

Good luck.

 

[Joe]

For all this talk about using the traveler as the primary control for boom position athwartship, I have yet to see a traveler that is actually designed for real time adjustment or even cleated for that matter. Most are set up just like the jib cars, with stopping pins or small lines to permanently set the traveler position. I have yet to see one set up for continual operator adjustment. Mine has locking pins, so my bungee setup is the only practical way to adjust it on the fly. Otherwise you stand a good chance of getting your fingers pinched. Its really not safe to adjust the traveler with much wind load, so you have to use the mainsheet.

Wow, Dave... you can see literally a million examples by simply googling "sailboat traveler". Here's a simple traveler system on my Cat 27.