Sail Trim Fundamentals – small adjustments to the shape of the sail can make the difference between being able to hang in a tight spot and being spat out the back.
The Basics Of Sail Trim
1. Get it Up –
There is almost always more breeze the higher up you get. Hoist Mainsails as high as they can legally go and both main and jib/genoa’s should be set at their proper tension. When trimmed to sail upwind in light to moderate winds, the sails can have a few wrinkles at the lower luff.
To get the setting right initially over hoist the sail and then trim in to load the sail up. This will allow the haliard to stretch and the tension to be correct. If not, ease the haliard a little until wrinkles just begin to appear at the luff.
In heavier winds, the haliard should be tensioned a little more so that the luff wrinkles just disappear. Conversely, pull on the Cunningham if the sail is at full hoist. As you leave the dock or beach, the tension will appear to be too much but once you sheet on the sail will attain the right shape.
2. Steer to the Sails Upwind –
When sailing upwind, sheet on almost as tight as you can. The helmsperson can then steer to the sails using the telltales on the luff of the jib to indicated whether the sails are stalled or not.
3. Trim To The Course On a Reach –
The steerer should point at the next mark (barring any other tactical decisions). Then the crew should adjust the set of the sails to suit. As a trimmer, you should constantly be adjusting the sails following the old adage “if in doubt, let it out”.
The maximum power for a sail is to have it trimmed to within a whisker of luffing. Watch the telltales that are spaced up and down the luff of the sail. They should all break evenly. If the top breaks first, move the sheet car forward ensuring that the sail is twisted perfectly for the angle you are sailing.
4. Block the Flow on the Run –
When running deep off the wind, the sails are no longer working like an airfoil. Set the boom at right angle to the breeze to present as much area as possible to the breeze.
Make sure that the trailing edge of the sail is set properly by controlling it with sheet and vang tension. The further out the sheet is the less effect it has on leech tension. When running deep look up and set the top batten at the same angle as the boom.
Downwind, with the sheet eased, the jib car needs to be moved forward to control the upper leech and give you as much power as possible.
On a boat with a symmetrical spinnaker, it is generally better to drop or furl the jib on a proud run (if your able) as it will affect the wind getting to the spinnaker.