Boat Handling Under Sail

Book Extract

Balance
The mysteries of this apparently difficult art are all locked up in the concept of balance. The classic explanation of balance under sail is based on the relative positions of the centre of effort (CE) of the rig and the centre of lateral resistance (CLR) about which the hull pivots. If the CE is forward of the CLR, the boat will try to turn away from the wind pivoting around her CLR. This is corrected by pushing the tiller to leeward, or steering the boat up to windward with a wheel. Such a tendency is known as ‘lee helm. If the CE falls abaft the CLR, the opposite effect will be experienced i.e. ‘weather helm’.

The above explanation only tells half the truth about balance, because it considers a static situation whereas there are inaddition many influential dynamic effects. Like the 'paddle-wheel' theory it produces a convenient myth which provides the most practical single guide to achieving a balanced yacht. Setting a larger headsail and reefing the mainsail in order to move the CE forward will help to reduce weather helm in an almost stationary vessel, but other factors such as angle of heel may prove equally dominant once the boat is moving ahead at her best speed.

Practical Exercises
Most boats have different handling characteristics in different wind strengths. Learning about them is likely to take time and the experience of varying conditions, but there are a number of basics which you can find out quickly. For example, which sail combinations are most effective?

Mainsail Only 
You might choose to begin with just a mainsail set. Some modern masthead-rig boats are reluctant performers under main alone. If this is the case with your yacht, the secret of coaxing her to windward will be not to try too hard. The most common mistake when working to windward without a headsail is to oversheet the main, because the boat simply dies and loses steerage way. Ease the sheet well and do not point too high. She should then come to life.

Headsail Only
Sailing under a headsail alone can be more encouraging. Most modern boats will perform adequately on all points of sailing without the main. This rather gives lie to the CE/CLR balance theory which we have described, particularly in a firm breeze many modern yachts sail faster and are quite well balanced under headsail alone. Once they are moving through the water and heeling, they can make up to weather carrying little or no lee helm. As with sailing to windward under main alone, it is a mistake to try too hard. The boat will be relatively slow to work up momentum, and if you sheet the sail in hard she will simply sag off to leeward and go nowhere. Start with the sheet well eased, have patience and allow the speed to build up; then you can sheet her harder and point higher as she accelerates. 

Note that nearly every boat will reach and run quite happily under main or headsail alone.

Full Sail To Windward
In order to determine how your boat handles under full sail, there are a number of characteristics which you need to be totally familar with.

• What is the boat's tacking angle? Try going about a few times, estimating before each tack where she will be pointing as she comes out of it. The number of degrees does not really matter; the important thing is that you can judge by eye where to tack so as to clear a moored boat to windward of you. There may not be a great deal you can do to improve the pointing ability of a boat, but it is vital that you know exactly how far to stand on in order to weather an obstruction on the next tack.
• What is the turning circle like when bearing away from close hauled? Attempt this manoeuvre initially without touching the sheets. Just pull the tiller hard to windward. Most craft will not respond well to this treatment. They start to bear away, then they heel and develop intense weather helm to the extent that the rate of turn slows or even stops. The boat then keeps going in a straight line with the helm feeling like a ton of bricks and the rudder stalled. She is thrown out of balance by too much sail abaft her pivot point, and by a more mysterious but equally vicious anomaly caused by her heeled hull form. After you have experienced this unpleasantness, carry out the same manoeuvre easing the sheets rapidly as you pull the helm to windward — even just the mainsheet. The result should be much more encouraging, with the boat coming upright then turning onto a downwind heading within no more than two lengths.
• How does the yacht cope with being over-canvassed, particularly closehauled? Narrow-beamed yachts are typically docile on the helm when over-pressed. They heel to large angles, start to lose speed and suffer an increase in leeway, but they remain easy enough to steer. On the other hand, wide-beamed boats, particularly those which carry their beam well aft, become very hard mouthed and difficult to control if asked to carry too much sail. They may even develop so much weather helm that it is almost impossible to stop them from tacking in a strong gust unless the mainsheet is eased.
• What are the effects of being under- canvassed? Looking at the other extreme of windward sailing characteristics, some boats don't seem to mind being ‘short of rag’. They continue to handle sweetly even under so little sail that they are only making a third of their potential speed to windward. Others cannot cope with being under-sailed. As soon as the speed starts to drop in a failing wind the helm loses any feel and directional control becomes very approximate. The situation is often aggravated by a left-over sea with waves much larger than the wind alone could raise. Certain boats can cope with this; others must be driven if they are to be kept under proper control.

Downwind
Here characteristics vary just as much from one boat type to another as they do closehauled. Narrow boats, heavy boats and boats with long keels tend to track well and are generally easy to sail fast in a straight line, but the price is often a propensity for heavy rolling. While this may be uncomfortable it will only make the boat difficult to control in extreme cases. Wide boats, light boats and boats with short keels often feel much steadier when sailed fast downwind, yet if over-driven they will broach, rounding up to windward and being knocked almost flat. Aboard such a boat it is vital to develop an awareness of the point at which broaching becomes a possibility. Offshore a broach can be disastrous, while at close quarters it may lead to expensive entanglements with other craft. 

Sternboarding
Unless she is yawl rigged, it is not always easy to sail a boat backwards. Nonetheless, it is a useful technique to acquire. Drop the jib during a practice session, bring the boat to a dead stop head to wind, then having first overhauled the mainsheet, or mizzen if you have one, shove the boom out as near to athwartships as you can. (For those unfamiliar with the term, overhauling means pulling all the the mainsheet out through the blocks.) The yacht will now begin to move astern. Steer as you would under power, with the rudder itself pointing in the way you wish to move the stern. Initially, the vessel will show a strong inclination to sheer across the wind, but if you can catch her with the helm she will build up enough speed for the rudder to overcome this and away you go. You can now experiment to discover how far off dead downwind she is prepared to sail without losing control. Some boats, notably those with short keels and spade rudders, perform this feat readily, but it is not unknown for gaff cutters of 35 tons displacement to reverse when circumstances demand.

Sternboarding is of great use when anchoring and can be a help when leaving a mooring — so it is worth taking trouble over.

 

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