Twist, Heel and tell-tales

Don Guillette · Jan 27, 2012

Geehaw: I'm only going answer on piece of your message in order to allow others a chance to chime in. In other words, I don't want to kill the thread!!

Your mainsail telltales are measuring exhaust so you want to place them at the edge of the sail. The most important mainsail telltale is the top one --- on the jib it's the middle one. They all are important but those two are the most important. When you buy telltales generally instructions are included but I place mine as follows: I place the top one maybe 2' or 3' down from the head and the bottom one about the same distance up from the clew. I then split the distance between the two for the middle one.

Placing them where you did doesn't really allow them to fully curl and duck behind the sail.

rpell1@msn.com · Jan 27, 2012

Hi,

My answer is from personal experience with my '91 Cat30 MKII in the conditions that I sail in locally. Whenever I have "nervous" passengers aboard that feel uncomfortable with heel, I raise my traveler, ease the vang and the mainsheet to create twist at the top of the main. This reduces heel and maybe a little speed. I learned this from my smaller 22' Chrysler and found it also works for me on my 30Cat. I also move my genoa car aft and ease that sheet as well. It's a balancing act, but with a little trial nad error, it seems to work well in my sailing grounds............predominantly the lower NY bite....stretching from the VZ bridge to the Ambrose Light. My best advice would be to try as many of the various techniques to see which one works for you. For me, that's part of the fun of sailing.

Good Luck and Happy Sailing.

geehaw said:
Well I have read two lengthy forums here on twist and they were very informative and gave me more info then I need except for one thing. Using twist to help keep heeling under control. I hear "twist the sail to spill wind"used often. So as an example; I am sailing along close hauled. the wind is blowing 15 knts. My passenger is a little bit scared of the resultant heel. My main tell-tales are streaming straight back. So to "spill the wind" I add more twist making the top tell-tales to not stream straight back reducing heel. Is this what I am understanding?

I understand that dropping the traveler will also reduce the heel, but wouldn't this drop your speed more then my understanding (or miss understanding) of adding twist?

And also I guess I am confused on Main-sail tell-tale locations. My main had none when I bought the boat. I placed some but I think I put them to far in. I placed them so the trailing ends of them are about even with leach. I think I should have put the leading edge of them at the leach?

Joe · Jan 27, 2012

Actually, I'd suggest setting your twist/trim for the average windspeed and sea condition, then play the traveller in and out to compensate for the wind's puffs and lulls, or the sea's peaks and troughs. It's much easier to steer with one hand on the tiller/wheel and the other on the traveller.... simply decide what angle of heel suits you and use the traveller to keep it there. The telltales will most likely not change for these subtle adjustments.... and not affect your speed the way you might think.

If the average conditions change for longer periods, then a trim adjustment would be in order.... otherwise I'd leave the trim alone and work the traveller in the short term.

As far as telltale placement........... the instructions are on the package when you by them. For the mainsail, three on the end of the top three battens is the norm.
Some folks will recommend a "mid-chord" pair of tales.... a liitle research in th archives will produce much more info. There is alsa a cool website http://www.arvelgentry.com/Telling_tales.htm that is more than enough information to make you an expert.

Good luck.

Joe · Jan 28, 2012

geehaw said:
I really wasn't really asking this because I want to control heeling. I was more asking because I keep hearing "add more twist to spill the wind" used in these forums. To me to spill winds means to adjust the sail ,in this case just upper part, so it is not acting as an airfoil but you are stalling it making it ineffective. I was using the example more as hypothetical thing rather then my experience. Last year was my second year sailing and I bought Don's book and chart, but not till end of season and have not had the pleasure to practice with it yet. I just went to the store it was 40 below zero. I so want to go sailing where it is warm!!!!!!! Greg

Yeah, greg... but the follow up question is "WHY" do you want to spill wind? The answer to that question is: to control heeling.

Bill Roosa · Jan 28, 2012

Hey Greg:
Do you understand the concept of angle of entry?
On an airplane wing it would be called the angle of attack. There is about a 10 degrees range of angles of entry that will work for most sails. Beyond that they flog or stall. The ideal angle of entry changes as you go aloft and the wind speed picks up. This is do to that old nemesis apparent wind direction. The boat speed (speed of the sail through the wind) and direction don't change but the true wind speed does as you go up the mast. This causes the apparent wind direction to "come back" as you go higher.
IF your sail was trimmed to have no or little twist then one part of it is not "entering the wind correctly" if the boat has any speed on at all. When you have the proper twist all the tale-tells will be streaming out on the main. This indicates that your entry angle is correct all the way up the mast.
By spilling the wind (sheet out, and traveler up) you are increasing the entry angle of the lower parts of the sail (more power down low) and decreasing the entry angle of the higher parts of the sail (less power up high). You would still want to have all the sail within the 10 degrees of permissible range of entry angles. Technically you are lowering the center of effort. This may or may not change the amount of drive you are getting out of the sail as the larger area down low will always produce more drive than the smaller area up high.
If you have a lot of twist then it becomes possible to have the more than the full 10 degrees of entry angle used from top to bottom. If the top is flogging (too small an entry angle) Then you would want to move the travler up more to stop that. This will cause the lowest part of the sail to start to stall. Stalling is "OK" as it will not hurt the sail like flogging would. It does reduce the driving force and has a nasty habit of cascading up the sail resulting in a ful blown stall. You should reef at this point.
So twist is great for "tweaking" in between reefs.
The other odd thing is the 10 degrees of permissible entry angle would also "come back" as you went up the mast as entry angle is an apparent wind value. I imagine it as 10 degree pie shape that has a twist as you go up the mast.

Don Guillette · Jan 28, 2012

geehaw: To restate your question -- does dropping the traveler down slow you down? The answer is yes because your changing the angle of attack to a slower setting. Does inducing twist in addition to dropping the traveler slow you down more? The answer is yes because when you induce twist the entire plane of the sail is no longer driving - only the bottom 2/3 of the sail is driving. You have "spilled the wind" out of the top 1/3 of the main or jib.That's a non scientific hillbilly explanation.

Here's how it works for me in real life. I'm sailing closehauled in 10 knots of wind sipping on a "tinney", all telltails are streaming and I have about 15 degrees of heel ---life is good!! Now the wind starts to pipe up and the boat starts to heel over more. The first thing I do is drop the traveler to bring the boat back to 15 degrees. If it was a puff, I'd wait till it passes and then move the traveler back to its originaly position. Let's assume it's a consistent wind speed change and I want to stay on the same course. The next step for me is to drop the traveler to get the boat back to 15 degrees but I find the boat is struggling to get back because it doesn't want to. Next, I ease off on the boom vang to induce twist. Through all of this I hope you've noticed I haven't even got into a sweat and still have the "tinney" in my hand and one foot on the wheel. All my sail trim controls are led back to the wheel so I can adjust them with one hand. I also can trim the jib with a 2' winch handle Garhauer built for me. All I'm doing is "playing" the sail trim controls.

Let's say the wind is still building and the boat is being naughty. Now the boat has gotten my attention and I've got to put the "tinney" down and concentrate on what needs to be done next --- adjust draft depth, draft position, drop the traveler more, induce more twist. Once I've reached the max on twist and the traveler now I'm going to flatten the sails as much as I possibly can. If that doesn't work it's time to reef.

What is the rule of thumb as to when a mate reefs his sails? The first time he thinks about it!!!!

When things ever warm up for you (I hope it's by June 1 because we've booked a 14 day Alaska cruise) take you boat out and devout some time to just messing around with it. Since you obviously, can't go outside now, light the fire and curl up with my book. By the time spring comes you'll know more about sail trim than 75% of the sailors worldwide becuase you'll know what each and every sail trim control on the main and jib is exactly doing.

RobertLangdirect · Jan 31, 2012

It is all about being effective -- not ineffective

geehaw said:
. . . to adjust the sail . . . making it ineffective. . . . Greg

I have a P-31, fractional rig. In my first two years of racing GOOD TRADE, my results were across the board, from first place to DFL by three or four hours after 50 miles. Last season I did much better, scoring several first, placing in nearly every race, and consistently beating boats that were always just ahead of me in past years.

Much of my success I attribute to Don and advice he gave me. With that said, I am not sure that there is much I can say about "twist" because I do not understand the meaning of it. However, reagding higher winds, heel, and effectively moving your boat, I will offer what I was told:

As you start sailing in lighter wind, you need a very efficient sail shape to move your boat. Think of a big, thick, fat, very round wing on a cargo plane (and ignore any supercritical design stuff for the moment). It works very efficiently at lower speeds and generates power to move your boat. But, efficient wings are a broblem as the wind picks up.

And so the wind blows harder and suddenly, your boat is heeling over. For the racer d ude in you, you think this is cool. For your passenger, it is scary. And probably neither of you notice, for your rudder and tiller, you have created a lot more work. Because your wing is too efficient for the wind load, it is trying to turn the boat up, you counter by adding rudder, and now create drag. The fact is, by having an an efficient-in-low-wind wing, you have a too-efficient-in-higher-winds wing, and you are left healing over, dragging your rudder, and going slower than you can, even as the excitement makes you think you are going fast. (See my avitar for a great picture of not goiing fast but having an exciting ride.)

So, on solution is to let out the main. That will, in effect, give you less effective sail area (and taken to an extreme, your whole main will be left flogging), but you will be sailing upright, and you won't be dragging your rudder sideways through the water. Think about that for a moment, what has more resistance, your main as it flaps in the wind or your rudder as it drags sideways?

On a fractional rig, in higher winds you can bend the mast by adjusting the backstay. This pushes the center of the mast forward, pulling the sail tighter in the middle, and flattens it out. Now, the formerly fat cargoe aircraft wing becomes more fighter like. It is actually less efficient, but more effective for higher winds. Less efficient in that it does not convert as much wind into boat energy, but more effective as it provides power without overpowering your boat.

I noticed the difference last October in a 35 MPH day with my 90% jib and bent mast, we never got luffed up but placed 1st in a local frostbite rase, and in November beat a boat that had consistent spanked me whenever I went further up-river to race.

But that is for fractionally rigged boats. Mast head rigs can't bend their mast -- DON"T TRY -- YOU CAN BEND YOUR BOAT TRYING -- so I guess that is why they talk about "twist." And as I said at the top, I cannot say much about "twist" because I do not understand the meaning of it.