K6 TUNING

David Hitchcock and Ian Nicholson won 5 races at this years championship and are long time class experts. Here David offers some advice and observations on the new class sails from North.

Overall the North’s offer speed and pointing improvement over the Hyde sails but only if properly trimmed for the conditions. Adjustments to the Hydes had far less affect than on the North’s so were in many ways more user friendly.

Jib
The flatter entry means that the forestay, luff and sheet tension are all important.
We set the luff tension so that creases were just visible throughout the wind range.
The forestay (adjusted by rig tension) worked best with some sag to create more depth in the luff/entry particularly in the lighter, choppy conditions.
The sheet tension seemed to be best when not tight in unless 20kts+
Jib car position inner position now in as far as 200mm (from 150mm in the tuning guide) in 5-10kts (flat water) then progressively outboard to prevent back winding of the main.
Clew board – use middle hole in all conditions. That said if all other controls are set up correctly, we used the next hole up in 5-10kts for more leech tension which worked well but is much more tweaky to keep that top leech tell-tale streaming!
Make sure that the leech line isn’t over tight and curling the leech. Adjust so that the leech is only just not flapping.
Many people commented to me that the jib was really difficult to use – this is almost certainly a product of having too much rig tension and/or luff tension.

Main
The number one rule here is to keep it sheeted in to the centre line at all times going up wind. We managed this in the complete wind range even up to the shroud breaking 25kts day! Obviously this is to some extent weight dependent so for the record we weigh in at about 185KG
Outhaul – 0 to 5kts tight : 5-15kts : eased with 50-75mm depth from boom at the midpoint. 15-20Kts : 25-50mm at midpoint. 20kts+ : tight
Cunningham – tighten to assist de powering as need. We didn’t use it at all until wind 15kts+
Vang – the sail has much less luff curve than the Hyde so needs much less vang. I preferred to keep the main in the middle with minimal vang tension and use the mainsheet to control the leech/bend. This appears to enable the main to stay central to maintain pointing and keep the bottom third of the sail driving. Lots of people complaining about starvation creases which are a product of too much vang and/or lowers too slack. In my view whilst the sail could do with a tad more luff curve to make a bit more user friendly its fine (and quicker)as it is. People just need to learn how to control the rig, vang and mainsheet tension.

Rake/Spreaders
The numbers on the tuning guide for the Hydes are still good except perhaps slightly tighter lowers in the 5-15kts range.

    1-5 knots 5-8 knots 8-12 knots 12-15 knots 15-18 knots 18-22 knots 22+ knots  
Shroud Tension
Up wind
15 20 25 25 25 25 22 Never
Shroud tension Downwind 15 25 31 32 33 35 35+ Let
Lowers Tension Upwind Fully Slack Just Slack Just Slack Just Slack Just Slack Just Slack Just Slack Forestay
Lowers Tension Downwind     7   10     Go
Rake Upwind 8670 8670 8670 8600 8600 8600 or less (1 full hole down on shroud plate) 8600 or less (1-2 full holes down on shroud plate) Slack
Rake Downwind 8660 8660 8660 8650 8650 8650 8650 downwind
Spreader deflection 235 >235 235 235 235 235 235  
Spreader Length 480 480 480 480 480 480 480  
Kicker loose Just tight tight tight Very tight max max Up to 15 kts aim is to get the top telltale on the mainsail to be just stalling
Cunningham off off off Just remove luff creases Just remove luff creases tighter max  
Outhaul tight Ease so foot not creased Ease so foot not creased tight tight tight tight  
Jib Car 150mm 150mm 150mm 150mm 100mm 50mm End stop  
Jib Clew Middle hole or top hole in flat water Middle hole or top hole in flat water Middle hole Middle hole Middle hole Bottom hole Bottom hole Jib sheet tension – ensure that top and bottom telltales break evenly. In 15kts+ always ease in gusts
Mainsheet Centre Centre Centre Centre Ease in Gusts  
Mast deck puller slack Just tight Tight – mast straight to spreader Tight – mast straight up to spreader Tight – mast straight up to spreader ease ease Note – better to keep more tension on the puller and use more kicker to bend the mast

Rake measured from mast tip to transom /hull join
Tensions measured with Loos gauge on the shore with no mainsail up