Four Elements Of Sail Trim

[Dave Conley]

Thanks

from a newbie. I've learned to make the boat go where I want - mostly. But from some recent races at the sailing club I'm in, I know I've got lots more to learn. Your discussion and answers to the questions were illuminating. Maybe I'll move up from last place next year.

 

[Don Guillette]

Four Element Of sail Trim

Dave: Racing to me was and still is, is all about becoming a better sailor. The problem is I went about it in the wrong way. Maybe some mates reading this can profit from my mistakes.After I bought my sailboat and spent 10 minutes behind the helm, I realized the skills I learned as a kid sailing on Narragansett Bay (RI) were not coming back to me. I needed lessons and attended a school in Newport Beach, Ca. I took every class they had (spent over $800) and got very good at docking, backing the boat, flaking sail etc. Unfortunately, I had little knowledge of how to sail the boat. I couldn't read the wind and had now idea how all the sail trim controls for the main and jib functioned.The sail trim information I obtained from dock mates and any sailors I talked to was full of half truths and the confusion and mixing of terms and definitions. I actually thought I was the sailing idiot of the world and everyone got it but me. I then decided to get into racing to learn how to sail. I contacted winning skippers and we had nice conversations but as soon as they realized I was a "newbie" that was the end of the conversation. I finally got a position on a boat with a pickup crew. Again, and unfortunately for me, I thought I was the sailing idiot of the crew. "A man does not know what he doesn't know" and I wasn't smart enough to realize these guys didn't know anything either. After a year of that nonsense, I realized there had to be a better way, because racing in itself won't make you a better sailor. I started reading everything about sailing I could get my hands on. It wasn't easy because the information you need to know is all over the place. For example, the information on draft depth or the outhaul might be on 15 different pages spaced through out the book. It took me a long time to put the information from 25 books, numerous videos and over 100 sailing magazine articles together. I knew I had all the information when it started repeating itself. I then went out and tested every concept on my boat. I kept what worked and discarded what didn't.If I had it to do over again here's what I do. Get a good book on the subject of sail trim. If you've got the time, you can get any book and go through the exercise of outling the material but I've already done that for you. I think my book is one of the best. It is written in simple English - so I can understand it. The SAIL TRIM USERS GUIDE is available through Sailboatowners.com. It explains the 4 Elements Of Sail Trim plus the operation of every sail trim control for the mainsail and jib. The SAIL TRIM CHART, which is also available, gives you every adjustment for every sail trim control for the main and jib for all wind conditions and points of sail. After you finish digesting my book and chart you now have more sail trim knowledge than 75% of the sailors worldwide. Now your ready to perfect your sailing skills. Start with club racing. Forget about winning. Treat each leg of the race as a practice session. Try to get 100% out of the boat on each leg, by putting into to practice the concept you've learned. Use all of your sail trim controls for the main and jib. Race only against the guy in front of you. You'll be amazed at how fast you improve, because you have a base to learn from.

 

[Paul]

mainsail draft trim unavailable to most

You describe trimming the fullness of the sail, but isn't it true that most sailboats don't have adequate controls to affect draft depth and draft position?Most Hunters (pre-2000 anyway) have boltrope-footed mains, and no ability to change mast bend. Sure, you can tug on the outhaul a little, and and change the halyard tension, but these are marginal inputs. The in-mast furlers have brought loose-footed mainsails to many boaters, and they have a bona-fide way to change the draft of their mainsails, at least in one dimension.But for most of us, all we can really control (in the main) is angle of attack and twist. We are stuck with the draft that the sailmaker stitched into the sail.I think if most sailors concentrated on and mastered these two elements of trim (twist and angle of attack), they would benefit much more than by trying to figure out what the "draft position" of their main is.

 

[Don Guillette]

Paul: Most boat are not set up like the Hunter.Only concentrating on twist and angle of attack is a mistake. Disregarding draft depth is like telling a pilot to disregard his flaps!! Draft depth and where it is located (draft position) on the mainsail is where the power to sail the boat comes from. Actually, by adjusting your outhaul, you are adjusting draft depth. The controls for angle of attack are the mainsheet and traveler. All the angle of attack does is move the boom in and out. It has nothing to do with adjusting the trim of the sail. The twist controls are the boom vang and the mainsheet.The controls for draft position are the boom vang, cunningham, mainsheet, mast bend and outhaul. The controls for draft depth are mast bend and outhaul. If your boat has these control - use them. If you don't have them then use what ever you have but be aware of what your missing.

 

[John Visser]

Cunningham

Don, Isn't Cunningham trim exactly the same as halyard tension? If not, why not?Thanks,jv

 

[Don Guillette]

Four Element Of Sail Trim

John: Absolutely, the Cunnigham is just like the mainsail halyard. It is a lot easier to adjust than the halyard, for me anyway. It was not designed by Briggs Cunningham as a repalcement for the main halyard but it worked out that way. I also have a cunningham I use on my jib. That one works well for me also. I don't like messing with the main or jib halyard.

 

[cole]

auto tension

I was looking at this tread and have thought of an automatic clew tensioning device like a screen door closer. I tried to make one from junk I had laying around the shop and the forces were tooo great. I welded a shackle to an all thread and rodded it through a 1.5” conduit@ 8” long. inside that, I had some neoprene rubber to act as a spring load. I was thinking of something like a motorcycle coil over shock.My thought is, when a gust arrives, the tensioner would release the clew to fatten the sail and power up the speed of the boat. As the wind abates and the speed increases the “coley” tensioner would retighten the clew and therefore decrease the draft of the sail thusly increasing the speed. I figure a 2-3" play is all i need.All these fun words tickle me. So Don what do you think?ColeS/V Bobs Degree

 

[Don Guillette]

Four Elements Of Sail Trim

Cole: If you ever perfect it you'd probably make a million bucks! A lot of sailors don't want to mess with their sail trim controls. In a lot of cases, they don't understand how they function otherwise they would use them. If you could make one automatic you'd make a lot of guys happy.The outhaul is a good example of a control that is not used. The outhauls controls the bottom 2/3rds of the sail and most sailors don't use it. In fact, on 75% of the Catalina 30's I go on, the outhaul is jammed in place. The internal boom system is a poor design. Another good example is the jib fairlead. Most boats I go on have that devise rusted in place. Its never been moved!The adjustable fairlead system made by Garhauer or Harken solved that problem so there is hope for your invention.Are you selling stock in your company?!!!

 

[Wanderer138]

Cunningham vs halyard

The cunningham is much more effective than the halyard for adjusting luff tension because all of the halyard tension applied at the base of the mast does not make into the luff of the mainsail. Here's why:a) some of the halyard tension is lost in friction going over the sheaves at the masthead so there is less tension at the headboard than you applied at the mast base. Tension is also lost in friction between the sail slugs and the mast track, so only a fraction of the applied tension actually makes it to the bottom of the luffb) some of the tension at the headboard goes into the leech as well as the luffAll of the tension applied to the cunningham tensions the luff (and nothing else) and does so where it has the most effect...in the lower half of the sail.PeterH23 "Raven"

 

[henkmeuzelaar]

Coley tensioner ba(ssa)ckwards, I believe

I love the idea but in order to make the boat stay "in the groove" (i.e. at near-constant heel and speed) throughout the puffs and the lulls I would rather see the tensioner flatten the sail in the puffs and fatten it in the lulls.......In fact, I believe that the Coley tensioner as described by the inventor ("when a gust arrives, the tensioner would release the clew to fatten the sail and power up the speed of the boat. As the wind abates and the speed increases the ?coley? tensioner would retighten the clew and therefore decrease the draft of the sail thusly increasing the speed") will make for a very rough ride by functioning bassackwards.Have fun,Flying Dutchman"Rivendel II"

 

[Wanderer138]

Coley tensioner

I think I get the idea (more or less) but I'm having a hard time visualizing how a device similar a coil-over shock could be rigged to change the shape of the jib.The closest I got was fixing one end of the tensioner to the deck directly ahead of the jib track and connecting the other end to the jib block, which would otherwise be free to slide back and forth along the track.In a gust, the additional tension in the jib sheet would pull on the tensioner and extend it, allowing the block to move aft on the track. This would decrease the angle that the jibsheet makes going from the winch to the block and up to the clew. The jib sheet is now slightly straightened and slightly lengthened, so the jib essentially eases itself. If the block moves aft it would also open the leech of the jib, increasing twist and spilling wind off the top of the sail, thereby decreasing the heeling force.As the gust passes, jibsheet tension decreases, the device retracts to its original shape, the angle of the jibsheet increases, the sheet shortens and the sail is trimmed back in. As the block slides forward, the leech closes, powering the sail back up.Easing the sheets in a gust makes sense, because in a gust the apparent wind moves aft. The sail then becomes overtrimmed (assuming there was no change in course) so easing sheets slightly is an appropriate response.If THAT'S the idea then I think "flatten" and "fatten" was an inappropriate choice of words because they imply that the draft of the sail should be changed in a gust rather than its angle of attack or twist. Especially when yuo consider that angle of attack is by far the easiest adjustment to make on a jib.PeterH23 "Raven"

 

[henkmeuzelaar]

Suah jib tensioner has merit; however...

it is not completely clear to me whether Coley's brainchild is supposed to act on the clew of a (loose-footed) main or the clew of a headsail. Since we appear to be redesigning the Coley tensioner anyhow, our first goal should probably be to use the force of the gust to try and keep the angle of attack roughly constant by heading up a bit in the puffs. Since this is more easily achieved through a small rudder adjustment than by trying to steer with the sails we are essentially trying to build some kind of "poor man's windvane". Over the years, I remember seeing several conceptual (and/or actually tested) devices using bungee cords connecting the clew of the mainsail -- or the boom -- to the helm via blocks and pulleys.Nonetheless, even when heading upn in a puff to keep the angle of attack roughly constant we still may want to depower both the mainsail and the headsail a little in a gust to keep the heeling force near-constant as well. This is where the tensioners could come in as long as they are rigged in such a way as to stretch the foot and open the leech in a gust, and vice versa.Flying Dutchman"Rivendel II"BTWPeter, I also agree with your comments about the practical differences between main halyard and Cunningham (with an eye on the various friction sources involved). HM

 

[cole]

coley tensioner

Perhaps i may be wrong when it comes to sailing but i believe that the clew outhaul would move the draft of the sail forward and back during a puff. I was also thinking about the main alone. Maybe the motorcycle coilover isnt the right mental picture.I have talked to several sailmakers in the rock hall area and they didnt stick their noses up. I do like the suah idea but where do you find the energy to change a sail without adversly effecting the other? I also think the rigging would resemble a rube goldberg invention. I love these forums when someone like don drops by and helps the commonerscole

 

[Peter Albright]

Cunningham vs Halyard

Back when I used to sail E scows on inland lakes, the halyards were fixed because you couldn't raise the main beyond the black stripe. The same applied to boom goosenecks on adjustable track.The two advantages of the cunningham were that it did not increase the size of the sail, and you could put more purchase in the blocks for easier control.The secret to using sail controls is to make them accessible and put in enough purchase so you can adjust them easily.