J/24 Tuning Tips
from Hood Sails



IMPORTANT Before stepping the mast, check it over to ensure that all the sheaves turn properly and freely, that all split rings etc are secure. File and/or tape any sharp surfaces, this helps prevent unnecessary damage to sails.

SPREADERS (Class Rule 3.5.3(h)). Line between tips of spreaders to the back of the mast 155mm. Length of spreaders should be minimum.

STEPPING THE MAST Set the mast heel so that the front of the mast is 315mm from the main bulkhead on the 'I' plate and ensure that the J measurement is set to the class maximum. With medium shroud tension and no backstay, there should be 30mm of prebend in the mast.

SHROUD TENSIONS An approximate guide to shroud tensions is given below.

UPPERS 400 450 600
LOWERS 300 400 600

The above figures are a guide to creating the correct amount of forestay tension for your sails. However, they will vary from mast to mast and boat to boat, but have been found to work equally well on both Kenyon and Proctor sections.

IMPORTANT When checking or changing shroud tensions site up the back of your mast and check that:


MYLAR NO.1 This sail has to work over a large wind range from calm conditions to 20 knots of breeze. Sail shape may be adjusted by fairlead adjustment, luff tension and sheeting.

Sheeting Keep an eye on the distance from the spreader tip to the genoa. (There is a spreader window fitted to your mainsail so you can see from the rail).

Under 8 knots of breeze the genoa should be eased 10-15cm off the spreader. (If the genoa is over trimmed the boat will stall quickly). Over 8 knots you can trim in progressively tighter to within 1 cm of the spreader tip. However take care not to allow the spreader to hit the sail in a quiet patch.

Halyard Tension Adjustment here is much less than with a conventional Dacron sail and should be just sufficient to give the sail a clean entry. Small wrinkles should always be visible from between the hanks.

Fairlead Position You will find yourself working over the front half of the track to power up for light airs or chop conditions move the lead forward. To reduce heeling movement and open the slot in a breeze move the lead aft and allow the sail to twist open a little.

JIB Change from the genoa to a jib in about 20 knots of breeze.

Sheeting Don't oversheet, have the forward part of the sail just touching the lower guard rail. The sail has two battens in the leech and as a quick guide to sheeting the lower batten should always be parallel with the centre line of the boat fore and aft and the upper twisted open slightly.

Halyard Tension Sufficient to remove wrinkles in luff, however, as the sail gets older, increasing tension will improve performance.

Fairlead Position Work over the front 3" of the track as per the genoa.


Light Air Position traveller to weather and centre the boom, outhaul eased 5cm.
Medium Air Ease traveller to centre, use backstay to depower in gusts. Medium kicker tension required. Outhaul eased 2cm.
Heavy Air Increase backstay and drop traveller in the gusts maintaining sheet tension. Firm kicker tension required, outhaul to black band.
In all cases use only enough cunningham to remove wrinkles on the luff.


Pole Height A second spinnaker pole ring is essential for running in light airs (Class rule 3.5.2.(f)). This should be fitted 12-18" below the normal ring.

Sheet and Guy Must be played constantly to keep the boat on its feet when reaching and prevent the mainsail blanketing the spinnaker when off the wind.

Care Handling your Sails

Your sails are all made of firm fabrics and should be flaked or rolled, not stuffed in to a bag. The 100% Jib should be rolled and is provided with tube bag for storage. Avoid allowing the sails to flog for any sustained period.