Twist

[Don Guillette]

By far the most asked question I receive concerns twist - got one today!! Beginners and some intermediates have trouble recognizing twist even though on any given weekend probably 50% of the boats on the water are over twisted.If you are the mainsheet trimmer or ever want to be one you have to master this proceedure.I go into more detail in my book The Sail Trim Users Guide but essentially the following is a proceedure that will allow any sailor of any experience level to set the EXACT amount of twist in their mainsail for the wind conditions where they are sailing closehauled. Closehauled is the time when you want to get it right. What we are trying to do is adjust for the built in twist every mainsail has. You can never get twist complelety out but you sure can put too much in.Step 1: Sail closehauled and set your mainsail and jib as best you can.Step 2: Position the traveler so boom is near or on center.Step 3: Crank on the mainsheet until the top batten is parallel to the boom. It can point slightly to weather. The top telltale should be streaming. If it curls, ease the mainsheet.Step 4: Now EASE the traveler down as you WATCH the leech of the sail from top to bottom. At some point either the top or the bottom of the leech is going to BREAK or flutter. If the top breaks first you have too much twist so trim the mainsheet IN. If the bottom breaks first you don't kave enough twist so ease the mainsheet OUT. What you are looking for is an even break from top to bottom. You won't get it due to the way the sail is constructed but you can real closeStep 5: Twist is now set but your not done yet. We want to tweak the sail and boat a bit more. Now pull the traveler up slowly until you induce about 3 to 5 degrees of weather helm. The boat driver will tell you when the rudder arrives at that point.Step 6: Periodically repeat step 4 until your comfortable with your boat and sail so you can just look at it and tell what adjustment you need.Sounds like it would take a bit of time to do this proceedure? If it takes you more than 10 seconds you have not got the proceedure down.

 

[Tim Hayes]

Funny you should mention your book...

I was literally setting here reading it as I went to check the forum.Great book by the way. It really helps on understanding how to trim you sails.Thanks,Tim Hayes

 

[Mike]

Thanks

Don, thanks for the tip on watching the leach flutter. I have a roller furler battenless main and have been looking for a better way to know when it's trimmed right. I'll print out your suggestion and try it come Spring.

 

[mortyd]

seems to me in the enclosed pioture the boat is heeled a bit too much and letting the traveler down would bring the boat back on her feet and allow the hull to sail more efficiently. no?

 

[Don Guillette]

Over Twisted

Rick: I can't cover every type of sail or boat (fractional / masthead) and have to deal in general terms. There are 2 controls for twist on the mainsail and the first is the mainsheet and the second is the boom vang. The use of the boom vang is a very close secondary and used for fine tuning. Thank you or the picture. I assume, since you submitted the picture, that you think your mainsail is perfectly trimmed and mirrors the jib. In the spirit of continuing this thread, I'm wondering if there is any improvement you could make to get more performance and power from your main? Anyone out there that would like to chime in?

 

[Puzzled]

Terminolgoy

Don,Am I the only person that doesn't understand what "EASE the traveler down" means? On my boat the traveler moves across the boat, not up and down!! Or do you mean downwind?

 

[Alan]

I'm dying to hear...

...your response to the picture, Don. I'm biting my lip to say nothing.I'm wondering Rick, if you have Don's book??

 

[Stu Jackson]

Traveler down means

to the leeward (downwind) side of the boat. The traveler is horizontal, but there's only one downwind side of the boat, and if you're close hauled, you'll surely note that the windward side of the boat is UP.!

 

[T J Furstenau]

Ok, I'll chime in . .

With a shot at the picture.Now, I don't have Don's book or guide yet, but my brother owes me a belated Christmas gift and this is what I'm looking for.My first instinct when I saw the picture was this - too much twist towards the top (i.e. top batten in line with boom). To fix this I'd likely look to tighten up the mainsheet or boom vang to get the boom down. Once that was done, seeming a bit overpowered (based on heel), I'd probably drop the traveler down (down on the traveler meaning to leeward). How did I do?Now I was only talking about main. Jib is a little hard to see behind that main, but if I was to stretch (and probably get myself in trouble), I'd say say slide the genoa car back a smidge and ease up VERY slightly in the jib sheet???T J

 

[Don Guillette]

Twist Quickies

Before I comment on Ricks sail (by the way I think it is a great shot of his boat) I want to throw out a couple of quick ways to set twist. Before I do that, I would bet that maybe 50% of the folks who frequent this forum have boats under 30'. The last 2 out of 3 boats I owned were a MacGregor22 and a Catalina25. Neither of these boats had all the controls I had on the Catalina30. The Mac did not have a traveler or a boom vang and neither did the Catalina25. The C25 had a very small traverler which was next to useless. The reason I'm mentioning this is to illustrate the difficulty in discussing some aspects of sail trim and being able to include everyone. My total direction here is to the beginner and interediates as I don't want them to go through what I did in order to figure out how to sail a boat. Anyway, suppose all you've got is a mainsheet. Suppose you have a mainsheet and a boom vangs also (the 2 controls for twist on the mainsail are the mainsheet and bomm vang) but you want a quick way to set twist or just get you in the twist ball park. Here's one way - just go through step 1,2 and 3. Set the top batten parallel to the boom. You'll be close. They other way is in step 3 and that is to notice the top batten telltale. It should stream. If it curls then ease the mainsheet until it streams. Why does trimming in the mainsheet and reducing twist make the mainsail more powerful and increase your speed? The reason is you have closed off the top of the sail so the power does not spill out and equally important you have increased the angle of attack. Those two items can increase your speed by a minimum of 1 knot.

 

[Don Guillette]

Puzzled

Puzzled: Probably your not the only one who gets confused with the term "ease the traveler down". Stu has given the answer and reason. Probably the best way for me to describe the action would be to use nautical terms like windward and leeward but they cause confusion too. I started using "up and down" years ago because it was easier for beginners to see for exactly the way Stu has described - you see the situation as opposed to ease to leeward. When I would tell beginners to do that they would just look at me!! They would then guess and 1/2 the time they guessed wrong.Another thing that would happen was when I asked them what tack we were on. Some would take forever to answer so what I did was put and "S" and "P" on the either side of the boom. All the beginner had to do was look at the boom. If he saw an "S" he knew he was on starboard. Probably sounds silly to the more experienced sailors here but to begginers it isn't so simple.

 

[Rick D]

I Always Set The Main First...

...on fractionally-rigged boats, which is what I owned most of the time (except for two mastheads). Rick D.

 

[Alan]

OK, OK here I go....

First dealing with the main:On a broad reach the boom should be hung out off the stbd quarter(port tack). With all that twist in the main in the pic a large amount of drive force is being used to heel the boat(slow) and the exhaust coming off the leach is killing the power(slow) that should be generated toward forward force.Broad reaching almost always requires a shift to vang sheeting. With the traveler having little affect on the main, the sheet must be eased to allow the proper angle of attack. But this increases twist and opens up the leech. The vang flattens the sail, allows the correct angle of attack to be reached and still use the power in the sail to drive the boat forward(not sideways).Absolutely when beating, the boom needs to be located at or near centerline. As Don suggests, flattening this sail on a beat may be a problem due to the overhead plumbing. If that turns out to be the case then an early reef will be in order.Second:TJ has it right about the jib leads. The jib is way over sheeted and the car needs to be moved forward and outboard. The over sheeted jib is also contributing to the excess heeling and loss of forward driving force. With properly set sails, when the puffs hit more of their energy will be used to accelerate the boat and less to heeling. My biggest complaint would be I don't see any telltales on either sail. This makes it even more difficult to try reading the wind and getting the trim right.Just my 2 cents.......

 

[mortyd]

there must be a reason nobody wants do address my query on the heel in the picture; sail trim matters little if you're trying to push a daraggy hull through the water.

 

[Moody Buccaneer]

Heel not a problem here.

It is hard to be accurate from the angle of the photo, but as near as I can tell the heel is between 15 and 20 degrees (I put the picture into AutoCad and measured transom to horizon and mast from vertical angles). It is very hard to tell from the photo what the apparent wind angle is, but the sails look over trimmed to me. The boat is not hard on the wind, more of a close reach with the wind just forward of the beam. 20 degrees heel is not excessive on a reach. The large trough amidships, tells me the boat is close to hull speed, and looks very normal. All boats look about like that when powered up on a reach.The jib is sheeted in hard and the main has too much twist. Look at the twist in the jib on the boat in the background. The boat off in the distance is also sheeted too hard and heeled more than the boats in the foreground. If the sails were eased and the vang put on, the boat would be just as fast and heel less.

 

[Joe]

Rick... no telltales?

Alan's observation is exactly right, IMHO. I don't see any telltales. Do yourself a favor...... GET SOME!!! For headsail luff and mainsail leech. (Mainsail telltales are single ribbons attached to the top three battens at the leech. Headsail telltales are a minimum three pairs, red and green, spaced evenly along luff of sail. You'll find instructions in the packaging.

 

[Rick9619]

Thanks for "twisting" my arm

Thanks boys for the interesting thoughts. Had a friend take the shots. Before I got the boat I hadnt dont any sailing other than a Hobie so tis a big world. No excuse but in my defence, these were taken about 8 months after we bought her. We are now towards the end of our third year. Since then... Joe I have refurbished the main and put taletells on all the battens. Moody, yes she is pretty much at hull speed with bad sail trim.. tis amazing what you can get away with when it is a pretty good boat. That boat in the background might be caught in a puff which as I said are quite common in the waters at Point Loma. Mortyd are you saying that my draggy hull is a design flaw or that as Alan said I am probably "skidding" her through the water due to main trim? Hunters arent J boats but I personally will trade arriving at Avalon a couple hours earlier for good tunes, a comfortable cockpit with no rigging attached to the floor,and with enough room for an extra cup holder Alan I always enjoy your thoughts (no stroking here). I guess what we try to do is apply as much as you said not for speed but for efficiency, stress on the rig, comfort, and er...speed. I dont have an outer set of jib cars on the 336 so I do the best I can. It is amazing how much you learn when it is your passion and you have no ego to bruise. Once again thanks for all your thoughts and uh, howbout someone else step on stage, identify themselves AND there boat, and lets see what else we can learn.CheersRick

 

[mortyd]

i am saying neither, but asking, since i don't know your boat, are you sailing - as most sailors do - with too much heel and inducing drag, slowing the boat down, by doing so. most modern cruising hulls are most efficient sailing on their feet. forget america's cup pictures of giant boats that can't hold a six pack below.

 

[Rick9619]

Mortyd, If we want the combination of comfort and speed then usually 15 plus or minus a degree, seems to put the optimum amount of hull in the water to support the rig for the point of sail without getting the drag coefficent too hi.Cheers Rick

 

[Neil]

Parallel Top Batten

I have been following this topic with interest, but want to go back to Don's original text for an explanation of "Crank on the mainsheet until the top batten is parallel to the boom". Sitting trying to visualize this at a computer is not as easy as trying it on the boat. Do you really mean cranking on the mainsheet to pull the leach end of the batten down until it is parallel to the boom? Since this sail inspection entails looking almost straight up the leach, this strikes me as a quite difficult thing to judge from that angle. Maybe its very easy in practice... or am I misunderstanding the intent?