I have never discussed sail trim in the past few years but, eventually, your boss will buy a raceboat because they’re sexy. Or your mate will invite you over to sail on a proper yacht with stringy bits and sails. I suggest you take note.
Sails are the big baggy things attached to the sticks in the middle of the deck. They slide up on a track, usually secured by specially designed sliders that secure the sail to the mast (and booms on occasion). Hoisting the sails entails effort — either yours or that of the dedicated winch.
The winch is similar to a capstan in that it increases friction on the halyards (the lines attached to the top of the sails) so that a crewman can control the hoist while the other struggles to turn the winch or press a button to make it turn.
Some vessels have hanked-on sails that are raised by hand, or still others, by releasing the roller furling system to let the sail out. All of the sails have lines attached to the clew (the extreme end of the foot of the sail). This line is used to control the angle of the sail to the wind. These lines are called sheets and are usually wrapped around a winch and secured to a cleat — by a clutch or in a crewman’s hands at all times. This sheet line is critical, as it allows deck crew to trim a sail, changing the perspective to the wind, and ensuring optimal performance and results.
Something you must master in this regard is line handling. The loads on the sheets and other lines is exponential depending on the wind strength and angle.
Proper trim usually entails a solid leech, not too closed (full and open is often best), the foot either flattened if heading windward or opened as you progress downwind and with the fullness of the sail extending to the very top where it may be fully open. In the IACC days, it was common to have the lower part of the mainsail, close to the mast, loose and not under load as the upper and outer portion was under load, maximizing the performance of the vessel.
Spinnaker trim usually has the sail trimmed and full all the way to the top, although they too surrender and enhance performance under the same rules of physics. Finer trimming usually has the sail on the very verge of collapse, either backwinded towards the tack or fluttering on the leech.
Something you must master in this regard is line handling. The loads on the sheets and other lines is exponential depending on the wind strength and angle. Errors can be fatal and can cause major injury to both body and reputation.
Making an error for lack of skill (as they can be extremely dangerous) can be serious. Imagine if you were being hoisted up a mast; would you want someone inexperienced below on the winch or would you prefer having an experienced crewmember that won’t let you down in every sense of the word?
The same thing applies to sails under load, so pay attention. Be sure to learn what you cannot imagine, as it is truly a mariner’s skills and tradition that make up the dynamics and assures slick, secure, and smooth operations on deck.
This article originally ran in the July 2021 issue of Dockwalk.