By Lloyd Collings (Two time Optimist Worlds representative for Australia; YV Junior Sailor of the Year 2009)
To be able to sail fast in light breezes first of all requires a certain frame of mind which can be difficult to achieve while racing. Unlike in strong breezes where some aggressive ‘pump up’ preparation can be helpful, in light breezes you should be confident, but relaxed and focused on technique. Worry/anxiety is your worst enemy in light winds, and is very common in Opti sailors who try to over think the situation.
Achieving the proper light weather technique will go a long way to getting you into the top group in an Opti fleet. Before this can be accomplished however, you need proper rigging and tuning.
1) The sprit: anywhere from no crease to a large diagonal crease in the sail can be fast, depending on the type of sail and how deep it is. Fuller sails like the J black or red require large creases, whereas flatter sails, e.g. the North XM-08 or Dzero6 need only a small crease or no crease. As a general rule, the more the wind dies off, the bigger the crease should be to prevent the leech from closing, while allowing you to maintain height.
2) Outhaul and luff: a common mistake is over loosening the outhaul in light air. Pull on until the gaps in between the ties where the sail drops away from the boom disappear. The luff should be the same (taught but not tight).
3) Vang and rake: Vang should look slightly slack going upwind, but cleated in preparation for the downwind. Rake should be measured as approx. 2790-2810 range.
Remember these settings should be used for only light to very light conditions, namely around 0-6 knots. The sail should then look more like a spinnaker from above 6 knots until the point you cannot keep the boat flat when fully hiked.
Achieving the Proper Technique
The Basics
At a certain sailing ability somewhere in the intermediate range, three common, basic instructions are needed. These are:
1) Pull on/let off the mainsheet to the correct position (Main).
2) Sit in the correct position (Body).
3) Steer the correct course (Tiller).
Once these three basics are done properly, you can go into a bit more depth.
More Depth
The most common cause of going slow, upwind in light weather is having a bad flow of air over the sail. Assuming the proper rigging/sail shape tuning, this is mostly caused by choking off the sail due to slight over sheeting and/or bad steering.
The mainsheet - In below 6 knots (very light air) it is usually favourable to ease the mainsheet out slightly more than usual to keep the leech open and avoid choking the sail (quote Lachy: ‘you have to let it breathe’). It is very helpful to have a good sense of whether or not the leech is open or closed by simply looking at it; however this takes time and practice. The simplest way is to watch the leech tell-tale. If it is hooking around the back of the sail then you are over sheeted. Ease the mainsheet, and it will flow straight back. If it doesn’t and the leech is still closed, don’t ease the mainsheet anymore as you will lose too much height. In this case there is probably something wrong with your rig setup (e.g. an over tight sprit). You only need to check the leech a few times on the upwind to get it right, and then just pull the mainsheet in the same amount after each tack to keep it the same.
Steering - Once the mainsheet is fine-tuned, it is a simple case of correcting your steering so that the tell-tales on both sides of the sail are working properly. In light conditions the tell-tales become extremely important to get right, as any disruption to the airflow will interrupt the boats momentum. Therefore you should spend a large amount of time on the upwind watching the tell-tales and correcting any steering mistakes.
Other things to look out for
Upwind Body Positioning: Upwind, the boat should be sailed completely flat, unless the pressure on the sail isn’t enough to keep the boom from swinging into the middle of the boat, in which case you can heel the boat slightly to leeward (only occurs in 0-3 knots). Lighter sailors can sit on the thwart upwind however it is not a good habit to get into, as the heavier you get, the more the bow will push water and it becomes essential to move back. It is very important for the boat to maintain forward momentum so body movements should be kept to an absolute minimum. This is why it can be advantageous to sit on the bottom of the boat instead of kneeling, as it is easier to keep still in the boat, and see the tell-tales. If you are going to kneel, make sure you keep your head away from the boom, relax and keep very still. Any necessary movements should be as smooth as possible. If there is chop you can use some body kinetics, but only if it is done properly. Just leaning forward and backward without thinking or watching the waves (as many Opti sailors do) will only slow you down.
Downwind Technique: Downwind, try to keep the boat kiting on a constant heel, with the sail well eased. You may need to ease the sprit in the case of a vertical crease to free up the sail. The ability to kite the boat consistently comes with the right technique (legs turn sideways and locked into the boat, body facing forward) and lots of practice. Similarly to upwind, if it gets so light that the boom falls into the boat, go forward and push it well past 90 degrees, and then quickly kite the boat to windward so that gravity holds the boom out (Nikki will remember this one). Again, keep body movements to a minimum.