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The power of light airs

14 April 2014 Michael Coxon

The crew of No Star put their tuning tips to the test during the regatta at Gosford

"The crew of No Star put their tuning tips to the test during the regatta at Gosford"

Photo by:
John Curnow

In itself, sailing should be more than enough to entertain the sailors. Alas, otherwise, why would one do it at all? Now when you cannot sail and you have a captive audience of competition-hungry sailors, what do you do? Well, entertainment shifts indoors. Don't get too carried away there, for the lights were on, the blinds were up and everybody was facing the same direction.

The organisers of the recent NSW Etchells Championship held at the Gosford Sailing Club came up with a good response to the problem of sailors on shore entertainment. You simply take a bunch of legends, including the moderator, Nev Whitty, and you cover off as many subjects as you can squeeze into an hour or so.

So there you are with a panel that included Grant Simmer, Steve Jarvin, Phil Smidmore and Doug McGain, all overlooking the AP as it got more sodden from the rain and barely moved whilst awaiting the wind to fill in. In the early afternoon Huey did let everyone go racing and it seemed everyone had paid total and complete heed to material delivered earlier. Nearly all 39 boats of the fleet arrived at the top mark for the first time of that day's first race, virtually at about the same instant. Apart from being a wonderful spectacle, which it most certainly was, it also showed how good the Etchells Class is at sharing the knowledge. All were happy with what the that group love in had provided for, even though one panellist was heard to say to the messenger, in total jest, "What did you have to go and do that for?"

This was the second day of the regatta and the previous days racing was conducted in light and variable winds, so after some discussion on current class politics the floor was invited to asked questions and a local sailor from the back of the room piped up with, "How do you make these boats go in light conditions?"

This lead to a healthy debate amongst the panel, who all offered sound advice, if not necessarily providing the amassed sailors with one simple pathway for the day's racing, which would be conducted in similar conditions. Now by chance I was asked this very question by a crew on the dock only a few minutes earlier, which we had discussed in detail. So being fresh in my mind, I then offered to share our discussion with the room.

Firstly we identified the problem, which we also had experienced the day before and I had given some thought to overnight. I recognised the issue to be a lack of 'power', that with our set up in the light airs we had been unable to generate as much power in the sails and rig for the crew to hike their weight against, as compared with the fast boats on that first day. In simple terms we were sitting inboard, whereas the fast boats were hiking.

We had made some steps towards optimising for light airs, including adding rake and softening our rig, but as it turned out, not near enough. So, in working with your preferred tuning guide, let's walk through the basics required to prepare yourself for optimum light air upwind performance.

The goal is to pre-bend your mast, which absorbs luff curve and sags your forestay. These are both positives, as the main tends to be too deep in light air due to the excess luff curve and the jib is too flat, due to lack of sag in the forestay. A deep jib entry gives you a friendly jib entry and an even nicer skipper!

Rig set up

  • RAKE
    Adding rake increases weather helm, which in turn gives you more consistent feel through the helm and helps the boat track in light airs, which in turns improves height
    Easing the stays relaxes the rig and makes the spreaders less active. Note my good friend, Grant Simmer, disagrees with me on this and prefers to sail with similar side stay tension in all conditions! So have an open mind with this one.
    Chocking behind the mast is a very efficient way to both pre bend the mast to flatten the main and to sag the forestay and deepen the jib entry. Remember to play with the amount of pre-bend that suits you for the conditions and this will include simply letting the mast float. This will help you achieve your goal of flattening the main entry and you now need to ease the outhaul to induce power into the lower main.
    Moving the step aft is another control of pre-bend and also renders your spreaders less active. It is similar to moving your side stays forward on the chain plate.
    Easing the lowers sags the mast to leeward at the spreaders, which both increases pre-bend (distance between main clew and spreaders) and effectively rotates the luff to leeward, and thus mainsail's leech exit to windward, increasing the return and thus power.

Sail set up

Think about your main and jib top battens before you hoist. Take the top batten out of the jib for added power. Consider either reversing the tapered main top batten, which will flatten the sail entry, or put your light, untapered top batten in the sail, all the while remembering that soft tension is best in light airs.

    Set the jib up so that the skipper is comfortable to sail around the entry for the conditions before you then focus on the main. Use soft luff tension, car forward and soft sheet, to make the middle batten align parallel with the centreline of your boat. This is a consistent reference. Remember, being a high aspect jib, if you ease/twist the sheet too much then you will give away horsepower.
    Starting with both forward and aft chocks out, the goal is to establish even arcs in the draft stripes, not the knuckle forward hockey stick section. So you achieve this by bending the mast with the backstay. However, if when tensioning the backstay you then start to loose the nice jib entry already established, stop on the backstay and add an aft chock. This will sag the forestay further and then allow you to use the backstay as a fine tune to achieve the perfect jib entry and acceptable main sections. The more pre-bend you can induce without adversely affecting the jib entry, the firmer you can trim the main, which generates the 'power' we have been referring to all along.

So there it is. Power, the variable we recognised as our weakness in light airs, is certainly within our control. In OD racing I believe the best tool at your disposal is observing the boats around you. If they have an edge, quickly observe and adapt your set up and trim to match.


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