Main Halyard Adjustment

Oakcliff Sailing Center Ker 50
Could use a main halyard ease!

By Keith Church, Quantum Sails, Chicago

Ed. Note: Keith Church, Quantum Sails Design Group, Chicago took the time to write this article about main trim during an extremely busy pre-Mac season. I am glad that Keith chose to focus on two main sail controls, the main halyard and the Cunningham and not try to squeeze a whole main trim study into 500 words. So, I’m sure there are going to be many questions about main trim that are not answered here. Please post those questions here to the blog and we will get them answered.

An answer to a question from the Crowley’s Advisor Number 1: Club Racers: Should I use halyard tension to shape the main on my sailboat?

Thanks for the question Rob. Yes, you should use halyard tension to help shape the main on your sailboat - but, how? The effects of increased halyard tension are to draw the draft forward as well as flatten the entry of the sail and the leech. You should be able to see this shape change in the draft stripes. If you have not seen this effect before, have one crew member ease and tension the halyard while everything else stays untouched. As halyard tension is increased you will see the draft (deepest part of the sail) move forward. Essentially, used to deepen and flatten the draft of the entire sail. If sailing upwind and using the halyard to gain max luff tension, it is not an option to use the Cunningham to tighten and loosen the luff. So, set your main halyard tension less than maximum for the conditions so that you can use the Cunningham to fine tune the halyard tension. Typically, you will want more halyard tension and therefore a flatter sail in more breeze, and conversely, less tension in lighter air.

Additional tips:

Host your main with your boat in reverse to lessen the wind effect and make sure the vang and the mainsail are released and free to run so you achieve maximum hoist. In medium conditions of 10 - 15 knots with your sail almost all the way up, your luff should be just tight enough but not boned-out, eliminating either all the sag in between the sliders or wrinkles in the luff tape. On one design boats and boats using measurement rules, there will be a black or white band towards the head of the mast. You should not try to hoist over this band. If your sail hoists above the bands, you will want to call me.

Using a magic marker, make a horizontal line on both sides of the sail luff somewhere in the first 2 to 3 feet and above the Cunningham where it is visible to the driver and tactician.
Using multiple color strips of tape, the mast person can overlap the strips on the mast to reference conditions; for example, light (4 - 10), medium (10 - 18), and heavy (18 - 25) to start. You have just set a gauge for halyard tension. As you get used to using this gauge you can add more reference points overlapping different colored tape on the mast. On my boat, I have 6 reference points over 2 inches.

Other speed gauges for the main can be done using stick on number for the outhaul, Cunningham, and boom vang. Mark the sheets with magic marker and put reference points in tape on the deck. By doing this. you are calibrating your mainsail speed related controls so you can reproduce fast trim. This also helps bring a new trimmer up to speed when switching positions in long distance races. The best time to set-up these gauges is during a long distance races as you will most likely see changing conditions.

Feel free to contact us about setting-up additional gauges for:
Cunningham
Outhaul
Vang tension
Mast butt position
Mast partner position
Jib/Genoa halyard
Rig tension
Backstay tension
Jib lead position
Jib trim angle
Rudder angle
Fore-and-aft boat trim
Angle of heel
Mainsail and jib sheets
Traveler car position

Caution; Cruising Class In-Mast Furling Mainsails:
In regards to your in-mast furler, the halyard should be tight, do not loosen it to shape the mainsail because it will most likely cause you to foul your mainsail furling it back up. Don’t try to bend your mast as this will be costly. Use just your outhaul to create shape. Sorry, but this is the main drawback to the convenience of an in-mast furler - a pretty flat sail. All is not lost, let's talk about an A3 asymmetrical spinnaker to enhance your sailing experience and put some excitement back into your sailboat. After all who wants to go upwind with a in-mast furling mainsail anyways.

 

Keith Church | Quantum Sails Design Group

Loft: (312) 225-0801, Cell: (312) 371-6929keith@quantumsails.com

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