Trim guide
click=menu Trimming the mast, bend, rake, shrouds... Updated: 2008-05-01 Comments

This trim guide aims to provide a basic race trim for the new mast. It is based on many years of racing in the class. Trimming the mast cannot be done too thoroughly. It is easy to ruin a perfectly good mast by sailing with a sloppy trim.

Setting the mast

When setting the mast, there's a few things to remember. Set the cap shrouds first, then the head stay. From here on we don't need the crane. There are two chain plates in each side. The Cap shrouds should be attached to the most forward chain plate. The head stay should be approximately 11,70m. Adjust with toggles. 


The rigging screws should be well greased in "rigging screw oil". It is much easier to trim the rig, if it is possible to tighten the screws by handforce. At high tension there is also risk of cold welding. 

  1. Release cap shrouds, backstays and anything else. Make sure mast is completely ofloaded.
  2. Set cap shrouds so that the mast is vertical, straight and upright (*)
  3. Tighten cap shrouds to max by hand.
  4. Set lower shrouds so that the mast is still vertical, straight and upright. (*)
  5. Tighten lower shrouds to max by hand, then release by 2 or 3 rounds or until the mast does not bend aftwards on the middle.
  6. Pull back stay all the way down. That's approximately 15 centimeters (on the wire) from being released.
  7. Handtighten capshrouds. Check verticality. Apply two to five rounds more on capshrouds using tools.
  8. Release backstay.

When done take a note of the hight of all rigging screws. Save the note for next year.


  1. Look up the mast track. It should be straight. Attach the main halyard to the gooseneck, and look again. 
  2. The mast should point aftwards. Old masts should be prebent. New masts are stronger, and they don't need the prebend. New sails are made for new masts, so normally the mast should be straight. Again attach the main halyard   to the gooseneck and check. Max prebend is 8cm according to class rules.
  3. The cap shrouds should be very firm - almost as a brick wall. 
  4. The shrouds should be rather soft, but not dangling.
  5. The headstay should be quite hard and it should give a distinct "singing" sound, when firmly hit by a medium sized screwdriver. Hmm. The sound is kinda like firing the guns on the Millenium Falken.)

*) Verify verticality 

Verifying verticality is done using the two ropes, - the spinning pole uphaul (shrouds) and the jib halyard (cap shrouds). Attach a fishweight at the end of the rope and hook it onto the rigging screw, then set the length of the rope so that the weight display is in the middle of the scale. Move the weight from side to side. A less technical approach is to tie something to the end of the rope like - say a liter of Orangina. Swing it over the side at the rigging screw and mark the height with a pencil. Move the bottle to the other side. Measure the distance of the mark to the deck. An even better approach is to simply use the length of the rigging screw. Just set the mast, and trim it measuring the length of the rigging screws. Naturally you should verify that the length of the shrouds match before setting the mast. 

That's it. The mast is now in basic trim. 

Further adjustments will be neccesary. After a week all the tension has bent the boat out of shape, and the rigging screws might need minor re-adjusting. Also, - depending on the sails, local winds and waves, you might need to tune the tension on the lower shrouds. This should be done at sea in order to see the effect. 




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