Many don't really know the difference between a spiral and a spin. How is that? You also hear of paragliding accident which starts 'one side of the glider collapsed and he immediately started to spin very fast towards the ground'. This sounds like a spiral, not a spin.
Spins are pilot induced. That means a glider will only spin if the pilot pulls one brakeline so that the half of the wing wil stall. The spin will continue as long as the pilot holds down the brake, and will recover as soon as he completely releases the brake. Another way of entering a spin is by having an collopse or cravate The collapse causes drag which causes the glider to turn, and the turn will continue to increase in severity unless the pilot does something about it. The speed at which a spiral can start and increase can be quite alarming . Spirals can become so severe that the G force can make a pilot black out if he does not stop it (unlike a spin where there is very little g force).
By having a cravate at one side of the glider, will cause one side of the glider to move faster than the other. The result (if not doing big airs) is a spin.
Spirals are different. In normal flight they are simply the extention of a steep turn that continues for several 360's. The pilot builds up speed as he is thrown out horizontally from the rotating glider, which can be turning so fast that the leading edge can be pointing towards the ground.
To stop a spiral, you must turn in the opposite way by applying the opposite brake. This is not as easy as it sounds, and if the spiral has already picked up speed you may need to use so much force that you have to use both hands on one brake to pull out of the spiral. Even if you stall the glider this is better than being locked into a spiral where your rate of descent can be in excess of 20m/sec.
The important thing to remember is that a spin is pilot induced and to get out of it you must completely release both brakes. A spiral is often caused by a collapse and to stop the rotation you need to counter the turn and pump out the deflation. So if we return to our accident report we can talk the pilot through the incident: 'one side of the glider collapsed and he immediately started to spin very fast towards the ground'.