Spring is made to release sheets up to 20mm in strong wind gusts.
It is used for:
– Self-release sheets system in strong gusts when sailing upwind, used to avoid luffing and drifting of the boat
– It is possible to adjust the amount of sheets releasing by means of mainsheet post positioning lower (away) from the main boom so the system will function as “softer spring”
– Jib releasing during gust while sailing down the wind

Advice:
– During wind shifting, conditions put mainsheet post app. 20mm under the boom, and under normal conditions put mainsheet post as close as possible to the boom.