The purpose of this tuning-guide is to give our clients in the X-99 class some guidelines on how to get the most out of their North Sails. The tuning guide is made by Mads Christensen

Follow the guidelines, but always experiment and try finding your own trim. The weight of the crew, the balance of the boat, the stiffness of the mast together with specific local wind and sea conditions all have influence on the fastest and final trim.


Main traveller from Harken with automatic relase on leward traveller


Blocks for genua sheet is tied on the traveller instead of using sjakels


All blocks are tied with spectra rope instead of using shackles to reduce weight and increase flexibility

Deck layout


Special turnbuckels to ease trimming


Spinnaker bag system, which makes it possible to move the bag forward in the cabin when not using the spinnaker


1. Take off your forestay
2. Bring it to the front of your mast
3. Mark the forestay just under the black mark.
4. Put the forestay back in its original place.
5. Measure from the black mark on your forestay to the centre of the
    pin-bolt when put back on its place
6. The lenght should be adjusted to the actual wind speed according to
    below table

 Wind (TWS) Measurement 
 0-10 knt 225 cm
 8-16 knt 226-227 cm
 14-26 knt 228 cm

Mast step

1. Measure from aft bulk head to back end mast step. (28-36mm)

2. Centre your mast at deck level according to your shroud position

3. Measure your J-measurement (forestay position at deck level to front
    of mast at deck level). This measurement should be 3450 mm.
    Maximum J-measurement according to class rules.

Contact the X-99 Experts:

Mads Christensen