Tuning Guide - X-41
The data inlcuded in this comprehensive guide is the knowledge gathered from dozens of race days and inumerable days of on-the-water testing.
This tuning guide is mend to get a quick start up with the North Sails standard sails. All numbers should just be used as reference and rough guideline as too many factors interfere and making it impossible to give exact measurements.
For finding a good base which will be your setup in about 11 to 13 knots you should move the mast step as far aft as you can get it- till the step touches the frame of the boat.
Head stay length – Rake
The head stay length is getting measured through the jib halyard. Take the jib halyard and set it to the hight of the upper edge of the lower band on the mast. Now swing it forward to the head stay and mark the point on the head foil. If you want to make it realy accurate you should use a fish hanging scale so that you pull with the same force on the halyard while making the marks. Make sure the head foil can´t. move up and down on the wire. Measure the distance between the mark you made down to the hull aside of the head stay. The measurement should be 253 cm.
Tensioning your V´s and D´s
Check and middle or straighten:
- Chain - plate positioning to headstay
- Shrouds to mast (is the mast centred)
- Check if your mast is straight in the boat. As easy start up you can just use the numbers on the turnbuckles, but if you take it really serious you should not relay on them because they will just bring you close and not spot on.
- The base jack pressure is about 4000 PSI or 275 bar.
- Looking to loose gauge numbers this will be about 71 on the V´s and close to 38 on the d1´s.
- Sailing upwind in 12 knots of wind the d2 should be loose, meaning just heaving a bit of slag. Tuning this in the harbour - it is about 1.5 turns on from heaving slag in the harbour.
- The d1 should just be about heaving tension and getting loos in the puffs.
- The V´s will have tension all the time.
- Looking up the rig you´ll have a nice slight sidebent in the rig.
Changes up and down in the windrange headstay
In the light you should ease the head stay off. Check the length of the turnbuckle first so that you do not run out of thread or turns. In 8 knots you ease it about 8 turns if it is possible with your supplied thread and turnbuckle length.
In the heavier air you put turns on the head stay. In 18 knots you have about plus 12 turns on your head stay counting from base.
In general if you have flat water you go more – if you have waves you try less.
In general the windier it gets the more head stay you will need. A maximum is reached when you get close to the maximum PSI pressure given by the rig constructer (6000 PSI).
Your V´s and D´s
In the light you ease your V´s and D´s.
The V´s will be about 3 turns eased - D1 about 3 to 4 turns and D2 about 1 to 2 turns.
Above 13 knots you do not have to change the V tension. The rig tension will increase through the head stay tension.
In 18 knots you´ll heave about plus 2 turns on the D1 and plus 2 turns on the D2.
The exact amount of turns + / - 1.5 tunrs depends on you base setup, your hole boat setup, the exact bending behaviour of your rig (as every mast is a bit different) etc.
This should just be a rough guideline.
Misc Sailing notes
The boat likes inhauler. If you are not heaving to many waves and to big puffs you have a maximum of about 6 degree as sheeting point. 6 degree equals about 30 cm from the inhauler block position. Watch that you do not trim the foot to flat. Do not have creases in the luff above 12 knots of wind speed.
Be careful on the outhaul - do not go to flat to early.
Use the vang upwind above 12 knots of wind speed and a lot above 15 to 16knots.
You probably have to shorten the backstay so that you can put a lot of backstay on. Above 12 knots the boat likes a lot of backstay to straighten headstay.
Be carefull with the backstay above 16 knots when your headstay is tightened – do not over do it. Check from the side.