WHY NOT BLINDLY RIG ACCORDING TO THE SPECS PRINTED ON THE SAIL?Updated a year ago

You have bought all parts from the same brand but if you rig according to the specs printed on the sail it still feels somehow ackward.
Unfortunately every product has tolerances in production. And the bigger a product becomes the bigger the tolerances become. Therefore tolerances on a smartphone are hardly visible whereas tolerances on Windsurf equipment are non-deniable.
- The tolerances on the mast length are approx. +-5 mm.
- The tolerances on mast extensions and booms are approx. +-3 mm.
Furthermore, there is unfortunately still no standard among brands on how to measure the length of booms and extensions.
- On a sail with all its panels the tolerances over the whole luff length can add up to another +-5-10 mm.
In addition, even with monofilm sails the luff stretches in the first 3 times you use the sail due to the massive downhaul tension.
Adding up all these tolerances you start realising why the absolute numbers printed on your sail (especially the luff length) can only be an indication to adjust your mast extension- and boom lengths.

To achieve the correct downhaul tension please make sure to only rely on the VTS (Visual Trim System) markers in the top of every DUOTONE sail.
Always keep in mind there are exactly 2 things either of them potentially killing at least 30% of your sails performance:
1. The wrong mast (see first point under MAST BASICS on every mast page)
2. Wrong/insufficient downhaul tension