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SHROUD TENSION GUIDE FOR J/24 NEWPORT SAILS

by Brad Read

This is a revised set of tuning numbers the Newport Tuning Guide incorporating the light air tensions that we are currently using. I also shifted the breeze strength around to a more accurate representation of what we are doing on our boat:

True Wind Strength	Knots	Uppers‡	Lowers‡
Drifter	0-5	18	12
This setting allows ample headstay sag as well as 2 inches of pre-bend. Mainsail backwind is reduced.
Light	6-9	20	15
On long Olympic courses we sometimes use this as an all-purpose setting, allowing for a light breeze to build and still be in the rig setting’s range.
Medium	10-13	24	21
Pre-bend is reduced to slightly less than .5 inches. This allows for necessary backstay tension and resulting headstay tension to begin depowering the rig in the puffs.
Medium Heavy	14-17	27	24
This setting is one that we use any time significant depowering is necessary. Lighter crews will go to this setting earlier and find that they are able to sail flatter and faster than if they stay at 24 and 21.
Heavy	18+	29	29
Whether at the top end of the 150 or into the 100, it’s windy and the backstay needs to be pulled on hard. With this shroud tension the lowers have pulled out nearly all the pre-bend, creating a very stiff mast that can be bent by the backstay to flatten the main. The headstay in turn gets extremely tight with the lowers and backstay forces working against each other.
‡ = Large size "B" Loos Tension gauge scale.

For tuning help, contact the North J/24 experts.