Spinout

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This information comes from the now-retired Torquay Fin Co. of Australia. See the original archived on theWayback Machine.


Spin-out

Spin out is problem experienced by every sailor at some time. The causes and solutions can be quite complex, but l will try and give some guidance. Spin out is easily recognisable because it feels as if your fin is broken and your board goes side ways in and uncontrollable manner. What is actually happening is the water flow detaches itself from the fin, causing cavition, ventilation or what ever you want to call it. The actual theory of this, l will leave up to the aeronautical experts. Spin out is nearly always caused by pilot error. Some of the situations that lead to spin out are as follows.

Low speed spinout

This occurs when you are just getting onto the plain and the fin suddenly lets go. The water flow over the fin is not fast enough to generate enough lift to balance the large lateral forces that can be applied to the fin at this stage. The faster the fin moves through the water the more lift it generates and then more force can be applied to it. If the problem persists

  • Use a larger fin with greater lateral resistance.
  • Use a fin with a higher lift foil shape or one that works well at lower speeds. (See section on fin selection.)
  • Don't load up the fin until board speed has increased.
  • Sail more off the wind until the board speed increases.
  • Check rigging of sail.


High speed spinout

This usually occurs suddenly and is caused by a rapid change in flow conditions over the fin. It most commonly occurs when the fin is operating at a angle of attack that is too high or in other terms you are pointing your board too high into the wind. In this situation the fin stalls because the water flow over the fin becomes detached. Unbalancing the fin or sudden changes in direction such as reaching off the back of a wave can also cause spinout. Once again this is usually pilot error. Whenever the board leaves the water it must be landed in a down wind situation where the board and fin are travelling in the same direction and your weight must be over the fin. This will maintain a smooth water flow over the fin surface. The same is true for wave jumping where the board must be turned down wind when landing. Whatever the cause of spinout it can be corrected by.

  • Having the correct fin for the conditions you are sailing in. It is no good trying to use an 11 inch speed fin when you are slalom sailing with a 6.0M sail. Generally if you are having problems try a bigger fin.
  • Having the correct rig balance. Sailing is a matter of balance. The rig, board, sailor, and fin must all be balanced correctly. Rigging is one of the first areas to consider. A sail not rigged correctly will exert too much side ways force and not enough forward motion. Plenty of downhall will help correct this. Mast position will change the center of effort of the sail which changes the whole balance of the board. A small change even half a inch can make a huge difference. Check board manufacturer specifications for correct positions. Boom height and harness lines will also effect rig balance as well the sailors stance. To avoid too much back foot pressure try to keep your body weight on the boom , this helps to keep the fin powered up. In conclusion if the balance is correct you can sail on the edge of control with minimal spinout.

Correcting spinout

Place your weight over the center of the board , take your back foot out of the footstrap and push down on the leeward rail to reattach the water flow to the fin.