On Friday, August 30, 2019 at 2:46:56 AM UTC-4, wrote:
Please check it and correct me if I'm wrong.

Usually the only springs in the rudder lines are those in front of pedals.. Those springs keep the whole rudder line in tension.

What happen if let's say the right rudder cable breaks: right pedal goes full forward and the same do the left pedal. The glider start circling left.. Possible correction: pull the pedals rack all the way back and put the left foot heel over the left pedal and pull back.

What happen if the right pedal spring breaks: right pedal goes back and left pedal goes full forward. The glider start circling left. Possible correction: pull the pedals rack all the way back and push hard the right pedal.

Depending on the glider, there may be additional options:

If the rudder cables are exposed in the cockpit, one may be able to grab a cable by hand and neutralize or reduce the rudder deflection. In the first example above, pull the left cable rearward, or push the right cable forward. It helps if you have a third hand.

If it's a two-seater, the broken cable may be between front and rear cockpits, so person in rear seat may still have rudder control (similar to broken spring situation above).