CHAPTER 9 Prevention against the broach


In fast, light, modern yachts, all issues of broaching must be seen in the context of surfing (see photograph below), but two points cover the prevention of all broaches: Keeping speed down You are far less likely to broach if you can keep your speed within sensible limits. The ideal is around that magical rate of knots your boat can make to windward in calm water. This will never be anywhere near the boat’s hull speed, but it is the rate of knots at which she is not making big waves. As hull speed is approached and the waves increase, the strains on the rudder rise heavily. Unless surfing is contemplated, check her enthusiasm by shortening sail. Keep her on her feet If a boat is allowed to wander from her straight course, the tendency to roll increases because the yawing will add centrifugal force to the mix of factors unavoidably already present. A good helmsman develops a feel for an incipient broach and checks the tendency to turn almost before it has begun. Proactive steering will help a boat stay ‘on her feet’ in awkward circumstances. Merely reacting to yawing that is already well under way is simply not good enough. Keep her going as straight as you can.


Surfing


Any sailing boat except the heaviest is capable of surfing down the face of a wave at speeds well in excess of her


theoretical maximum. She does not have to be ultra-light, although it helps. Once surfing, it is vital to keep any boat on her feet, because at such speeds one can rarely argue with the centrifugal forces if she starts to spin round. Some race boats designed for long periods of downwind work in heavy weather are exceptionally light, wide and flat aft to encourage stable surfing. The extreme beam renders their rudders liable to lift out of the water when they heel heavily, so deep spade rudders are standard. Twin rudders ensure that the leeward one is kept in the water. Surfing not only diminishes passage times, it is also extremely exciting, but it makes huge demands on crew at the helm and even greater ones of an autopilot. The average cruising boat is unlikely to surf for any length of time, but whatever the boat, the key to safety lies firmly in the driver’s hands. Anticipation is everything if the yacht is not to run out of control and broach. The initial tweaking of the helm as the yacht takes off down the wave is not unlike what happens when a dinghy breaks out onto a plane. A firm touch of weather helm to start with as the wind grabs her and she tries to round up to windward, then a readiness to steer hard the other way as she accelerates and thinks about broaching to leeward. Only feel can tell you what to do, and practice makes perfect. There is no need to be intimidated, however. A good helm will soon be managing fine in a boat that is not being driven to the edge. The exhilaration is highly rewarding.


Mike Golding in Open 60. MANUAL OF SEAMANSHIP | 99


Heavy Weather


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