In windsurfing, the failure of function of the fin equivalent to a stall of an aeroplane's wing.

When planing, the fin works like a wing, cutting through water at a small (several degrees) angle of attack, and countering the lateral drift caused by the wind. The sailor's foot pressure leverages the lift, keeping the board flat on the water.

```       =======wind=====>>

\  Force from the feet
V____________
/   board    \
~~~~~~~~+------------+~~~~~~~
-       ||f        -
Lift of <------||i   -
the fin        ||n      -
-     -    \/

(rear view)
```

If the pressure is too high, the fin loses lateral resistance as the angle of attack jumps up to around 45°. The back of the board is suddenly thrown leeward. Usually a bubble of air forms behind the fin.

Experienced windsurfers are able to recover from spinouts by guiding the board to the correct position with their feet, thus restoring the angle of attack of the fin. Furthermore, experienced windsurfers sense the moment of spinout and sheet in just as much as possible to bring the gear to the verge of spinout without actually tripping it. This is the fastest mode of the windsurfing board.

Excessive spinouts can be fixed by putting on a larger fin (or a smaller sail). Too big a fin though will deliver too much torque to the sailor's feet, and thus will be quite tiring.

When referring to cars, a spinout is one of the things that can happen when you enter a curve at a too high speed.

A spinout occurs when the rear tires lose traction during a turn, which results in the car pointing further in the direction of the turn than the driver would like. If the driver is able to correct this situation, what you get is a drift, or a skid. If the driver is unable to correct the situation, the car eventually ends up pointing in a direction that's totally inappropriate, and the car as a whole ends up stopping in the road pointed in the wrong direction, or sliding towards the outside of the turn - hopefully onto a wide expanse of grass, and not into a concrete wall.

Because spinouts occur when the rear tire loses traction before the front tires, spinouts typically occur in rear wheel drive cars that are trying to accelerate more than they should be during a turn. Also, because the act of braking transfers weight to the front of the car (reducing rear traction), spinouts can also happen with too much braking during the turn.

Spinouts can also occur through no fault of your own, for mechanical reasons, or if another vehicle hits your car during a turn.

You can avoid spinouts by not going too fast in a curve, getting really good tires, getting a really high-performance vehicle, or not turning. Trying to avoiding spinouts by driving a front wheel drive vehicle may result in understeer. You can still spinout in a front wheel drive car anyways.

Also referred to as oversteer (which also may encompass drift).

Apparently, you're supposed to hit the brakes during a spinout, hoping to slow your car down before it hits something...

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