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980 Posts
Discussion Starter · #1 ·
If I may comment regarding some of the questions by novice sailors regarding sail
trim and some of the technical and advanced
responses they get, let me say that there is
a very simple way for beginners to trim sail.

Since none of you are going to be trying out
for the olympics any time soon, use this very
simple technique. Set up your halyard and
outhaul hard for windy conditions to flatten
the sail and take the draft out of it. Set
them up soft for light conditions to make them baggier. Now, when you are sailing, start with the foresail and ease the sheet
slowly until the luff just breaks, then
harden up just enough to remove the break.
Do the same with the main. Your sails will
have the correct angle to the wind and you
will have smooth air flow over them.

Beginning golfers start out slicing. Beginning sailors almost always start out
sheeting in too hard. Here is an excellent
drill to help you feel the effects of sail trim.
It is expecially revealing in a dinghy.
Harden your main sheet right in until you
are well heeled while maintaining the same
bearing. In order to stay on your rhumb
line you will notice that you have to really
pull on the tiller. The rudder will feel like
a barn door dragging through the water and
your wake will be a mess. But you will be
tracking in a straight line. Now ease your
sheet and let her come back up on her feet.
Notice how you have to ease the rudder to
stay on your line. What is happening is
that when your boat heels, it sails on a
different underwater shape than when it is
straight up. This makes it want to turn into
the wind. You have to counter that with rudder. Thus the proverbial weather helm.
When you ease your sheets, thus reducing
the heeling, she sails on her feet, tracks
straighter, and you need less rudder which
reduces drag and thus you go faster. Do this
a few times over several ranges of heeling.

Remember, it is slot shape and leach tension
that determines the drive efficiency of your
sails. Ease sheet till the luff just breaks;
ease back in until it is gone. Keep her on
her feet and she''ll go well. Keep it simple
until you get some time under sail. Let the
wind tell you what to do. It will talk to
you through the luff of your sails and your
tell-tales coupled with the amount or heel
it gives your boat

Wishing you fair wind and a clean bottom,


Super Moderator
Farr 11.6 (Farr 38)
10,621 Posts
Use of the traveller is about twist in the sail. If you sight up a sail underway you will notice that a imaginary line drawn from the luff of the sail to the leech will vary in angle as you move up the sail. This variation in the angle of attack of the sail is called twist. Upwind, the mainsheet, traveller and backstay adjuster (on a fractional rigged boat) controls this twist. The more vertical the pull of the mainsheet and the tighter the sheet, the less twist that you have in the mainsail.

In light air, you want more twist. The telltales on the leech of the main should all be flying and to do so requires quite a bit of twist. Moving the traveller to windward changes the angle of the mainsheet, making it more horizontal, and allows more twist.

In heavier wind you wnat to blade out the sail(flatten the sail, reduce the angle of attack and eliminate twist). Moving the traveller car to the centerline,or even below the center, and tightening in the outhaul, halyard, backstay adjuster and mainsheet really flattens the sail and gives the boat a lot less helm and a lot more control. When reaching the boom vang controls twist in the same manner as the traveler.

Jeff H

980 Posts
Discussion Starter · #4 ·
Ahoy, SteveR23. Just saw your question to me. I''ve been remiss lately keeping up with all these different categories. jeffH is a very knowledgable and obviously experienced sailor and his advice is excellent. I recommend you read his stuff when you come across it. He covered this quite well. I''ll just add the following: Get on your boat with the main up on a calm day. Put your traveler right under your boom. Now, pull up on the end of your boom. You find that it can''t rise. Now let out the mainsheet and push the boom until it is off to the side, not over the car. Now push up on the end of the boom. See how it can rise? The further out it is, the more it can rise. This allows the sail to twist as jeffH mentioned. Now Keep the boom where it is and let the car move down under the boom end and take the slack out of the sheet. You are right back where you were originally, except that the car is down, not on the center line. Again, the boom can not rise and thus the sail will not twist. Generally speaking, in light air, you will have the car up to keep from adding tension to your leech because you want a fuller, softer sail. On a windy day, you will put the car down so you can pull more or less straight down on the boom, tightening the leech, eliminating twist, and maintaining a flatter sail shape. That is, if you sail has twist because of inadequate leech tension, you drop the car to leeward and tension the mainsheet. On a reach or run, you use the boom vang to control twist so the position of the car isn''t a consideration. On light days you can actually have the car to windward which will allow you to have the boom on the center line without the effects of downward pull by the sheet on the leech. Piddle with it. You''ll soon get the idea. Regard. dhartdallas
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