Asymmetric Sailing

När man byter till en snabbare båt så brottas man med nya utmaningar. Det är väl en del av charmen, även om det kan vara frustrerande att gå från en Laser till en 49er, från en Farr 40 till en Extreme 40 eller som i vårt fall från en J/109 till en J/111.

På papper skiljer det inte mycket mellan 109 och 111, men när man kan segla riktigt fort på undanvinden så blir det en helt annan båt. Och utmaningarna för oss är nästan lika stora som när vi gick från symmetrisk till asymmetrisk spinnaker.

I Asymmetric Sailing så tar man upp undanvindssegling i skiff, flerskrov och snabba sportbåtar som alla har liknande utmaningar. Bra resonemang och massor av praktiska tips från skarpa seglare i olika båtar.

Med J/111 så tittar vi mycket på hur man seglar små sportbåtar snabbt, framför allt Melges 24. Och här fanns många bra tips. Framförallt kring “marginal planing” som är det svåra register då man inte kan bestämma sig om man skall gå lågt med deplacementsfart eller om man skall hetta upp och försöka plana.

Asymmetric Sails + Apparent Wind = Fast and Fun

To sail successfully with an asymmetric spinnaker – or gennaker – requires you to start understanding what apparent wind is. Apparent wind is the wind that is generated by the boat moving forwards. It’s the same wind as you feel when you stick your hand out the window of a car when the car is moving, or it’s the wind in your face when you are cycling. It’s artificially generated wind, so you can feel apparent wind even when there is no true wind blowing at all.

Understanding the effect of apparent wind is crucial to sailing with asymmetric spinnakers, but it will also help improve your understanding of all types of sailing. It’s easy to think that, on a simple singlehanded boat like an Optimist, Topper or Laser, you run downwind just by presenting the sail to the “·ind and getting blown along, without any flow across the sail. Indeed that’s how most club sailors do run downwind in a Laser, but ask an Olympic standard sailor how they steer the Laser downwind, and they’re always doing angles, always with flow across the sail. They may be sailing a greater distance, but the increased efficiency by having flow across the sail more than makes up for the extra distance.

Unlike a conventional, symmetric spinnaker or the mainsail on a singlehander, the asymmetric spinnaker cannot function without flow across the sail. It is absolutely reliant on wind blowing across the sail. But once you understand this, and that by combining the true wind with the apparent wind generated by your forward motion, then you will discover that you can achieve much greater boatspeeds. Many asymmetric dinghies and multihulls are capable of travelling at least as fast as wind speed and in some extreme cases such as the AC45 America’s Cup catamarans, travelling in excess of three times true windspeed is achievable.

One of the fun by-products of asymmetries is that for the reasons just given, you can’t sail dead downwind – or at least it’s very slow and inefficient to do so. Because you want to maximise the apparent wind, you are always sailing angles downwind. Now the run starts to feel similar to an upwind leg, where any sailor knows that it is impossible to sail directly to the windward mark. Well, to some extent the same is true with an asymmetric boat . You have to sail angles, and that makes for a much more tactically interesting and challenging scenario.

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