Getting enough twist?

[Anthony Bavuso]

Don,The main sail for my hunter 25.5 I think was designed for a large amount of twist. And I have a problem most of the time getting enough twist so that all my leech tell tales will stream properly and not stall. For example say I was on a starboard tack, in order to get enough twist I have to set the traveler all the way over to the starboard side i.e. the opposite side the boom. This reduces the downward tension on the main and allows the sail to develop enough twist. Is this normal? The problem is that now with the traveler all the way to the stops on the starboard side, I cannot use the traveler to adjust the sail angle in the puffs. So I have to use the mainsheet and that of course changes the set of the sail.I have a fixed topping lift. I am curious would it help me to setup a running topping lift and in the situations where I need more twist I can haul in on the running topping lift, moving the boom up, allowing for more twist. Is this a common practice?

 

[Wanderer138]

Excellent question!

I have the exact same questions regarding my H23. Older sail trim manuals do not dicuss the interaction between mainsheet tension and leech tension and the ability to develop twist in the main. I learned from a friend about pulling the traveler all the way up and easing the mainsheet down to put the boom where it should be in order to get some twist.I too have pondered using the topping lift to overcome the downward pull from the mainsheet (and vang) so I can develop enough mainsail twist.As for the traveler, I am replacing the existing Schaeffer traveler car and the spring-loaded stops on my 88 H23 with a new car (with two sheaves) and the 3:1 traveler tackle with windward sheeting. I am tired of adjusting the main in the puffs with the mainsheet. It is a pain, and as you so rightly pointed out it definitely screws up the trim of the sail.PeterH23 "Raven"

 

[Paul M]

I don't really like twist...

... unless I'm overpowered. Then, I might use twist to spill air while I was working up my resolve to put in a reef.If you're overpowered, and the vang is off, the wind should lift the boom plenty. If you've got the traveller all the way to windward and you want to deal with a puff, you're going to dump the traveller to leeward, so you're in good shape there.Me, I pinch higher in a puff, but I have to stand up to reach the traveller sheet, so I guess I'm too lazy to change the sail trim.

 

[Don Guillette]

Getting Enough Twist

Anthony: All sails have some degree of twist built into them by the sail maker. The problem is twist is a power robber as a twisted sail spills power out of the top 1/3 of the sail. In some situations that is exactly what you want to do, but in normal conditions you want to elimate as much twist as you can. Like everything in life - hitting a golf ball, kicking a soccer ball etc - there is a technique and here is a proceedure you should try to set the proper amount of twist for the conditions you are sailing in.step 1 Sail closhauledstep 2 Position traveler so boom is near center line of boatstep 3 Trim mainsheet until top batten is parallel to boom. Top batten can point slightly to weather. Top telltail should stream - if it curls, ease thesheet.step 4 Ease the traveler downObserve the top and bottom of the leech Top breaks first - trim sheet in ( too much twist)Bottom breaks first - ease sheet out ( not enough twist)step 5 Twist is now setstep 6 Pull traveler up to obtain 3 to 5 degrees of wether helm on the rudder.Try this method and see if it works for you.On the topping lift. Its only function is to hold up the boom when the sail is flaked. It is not a sail trim control as such but can be used in very light air to lift up the boom a bit to put some belly in the sail. That is the only other function it serves.

 

[Anthony Bavuso]

confused?

Don,I am confused regarding your statement: "All sails have some degree of twist built into them by the sail maker. The problem is twist is a power robber as a twisted sail spills power out of the top 1/3 of the sail. In some situations that is exactly what you want to do, but in normal conditions you want to elimate as much twist as you can."I thought that the point of sail twist was that in all conditions wind speed increases as you move up in altitude, therefore in order to maintain the optimum angle of attack for the whole airfoil the sail needs some twist between the top and bottom. Am I wrong? If not then why would you want to eliminate twist. Wouldn't instead of eliminating it, you would try to optimize it?