Stuart Jardine, J/24 national champ five times over, tells you how
to get the best results from your '24' and teaches you how to tune and
J24 was designed way back in 1977 and was soon established as the World’s
most popular One-Design keelboat, which it has remained ever since. The
robust construction has ensured that most of the older boats can still
compete with the new.
|Photo ©: Ocean Images|
Crew Clothing at full speed
The Class is established in nearly 40 Nations with well over 100 active
fleets and you do not have to go far in any country to get a sail in a
J24. Many of the most talented sailors in the world from Grand Prix events
to the America’s Cup and the Olympics have been attracted to the Class.
Sail shapes have not changed much over the years but the method of
sailing has been fine tuned. Tuning guides are provided by most sail
makers these days. They are all very similar in their approach, passing
down the accumulated knowledge developed over 25 years. It is worth
remembering that only a 1% increase in average speed would put you more
than 1 minute ahead on a normal length course.
The bottom, keel and rudder need to be smooth whether you dry sail or
have antifoul, however I am not suggesting, as some do, that you should
spend 200 hours under the boat. Profiling the keel to the minimum
thickness is usually necessary because they are often fatter on one side
when taken from the mould, computer cut templates are available for this
task. If you are working on an older boat ensure the keel and rudder are
in line and that the keel is not loose.
If your boat is heavy do your best to optimise both the mandatory and
optional equipment to ensure the boat is as near as is possible to the
minimum sailing weight of 1375 Kgs. This can be achieved by carrying
minimum weight mandatory items such as the outboard, battery and anchor,
in addition to leaving ashore most of the optional equipment like fenders,
warps and tool kits.
Three basic checks on the mast are necessary. First ensure that the
mast length is within 5mm of the minimum, then check that the forestay is
exactly to the maximum of 8670 mm from the sheerline at the stem to the
intersection of the mast and forestay. Then set up the spreaders with a
deflection of 155 mm having first checked that they are at the minimum
length of 760 mm. Finally, whilst the mast is down ensure that all the
sheaves are running smoothly. See the mast diagram set out in this article
and consult the Class rules.
the mast is up there are three items to optimise. One, set up the butt of
the mast so that the forward face of the mast at the foot is 2855mm from
the stem. This is done by measuring from the side of the 3rd bolt down on
the stem fitting, inside the forecabin back to the “I” beam 2730 mm and
scribing a permanent mark, then from there 125mm to the mast face. Then
ensure that the mast partners at the deck hold the mast at maximum “J”;
again see the mast diagram and consult the rules.
|Setting up the mast foot position|
click for full size picture
click for full size picture
Finally centre the mast by taking up the upper shrouds to 20 on the
model B Loos gauge or equivalent on other gauges. Measure back from the
stem to equal points on the shear line adjacent to the mast and then
measure in to the mast from each side. Chock the mast, remember the mast
gate (hole through the deck) is unlikely to be exactly centered. Then
using the genoa halliard adjust the length to just touch one side at your
mark, check the opposite side and adjust the upper shrouds until the mast
is upright. Then adjust the lowers to straighten the mast. At this point
you should have achieved a prebend of 30/35mm.
- The backstay should be disengaged whilst setting up as it could
influence your measurements.
- Stem fittings and “I” beams do vary, therefore the 2730 mm could
produce small differences; common sense is required in measuring the
final 125 mm. Adjust the foot to induce a 30/35 mm prebend. Three groups
of holes corresponding to the four holes in the mast step, centred 10mm
apart along the “I” beam both fore and aft of the mast should be
predrilled for ease of adjustment. I use these three sets covering a
length of 30 mm. Aft for more prebend in light airs, centre for most
normal conditions and forward for 30 knots plus.
- Consult your sailmakers tuning guide for recommended prebends as
they do vary a little.
The sail shape is ruled by the shroud tension as it both controls the
mast bend and forestay tension. There is a simple rule to follow; the
uppers control forestay tension and the lowers the mastbend. As you can
see from the table below, the balance shifts from the uppers to the lowers
as the wind increases. There are four basic settings but finer tuning can
be achieved once your crew have mastered the basics. All my measurements
are achieved using the Model “B” Loos gauge. The newer Pro Loos gauge can
be used, but beware, despite numerous checks this gauge tends to give you
tighter rigging; err on the looser reading is my advise.
|Shroud Tension Guide:|
|0 – 5
|5 - 10
|10 – 15
A gauge guide should be kept aboard at all times. It is also often
essential to know how many turns are required on the uppers and lowers to
bring them up and down to these figures. This can be written on the deck
alongside the shrouds for ease of reference and rapid adjustment, for
example between races.
For accuracy, ensure that the backstay is completely off and that the
boom is centred. Finally, when you have brought your rigging to the
required tension always look up the mast track to ensure that you have not
induced a bend to port or starboard.
Only one golden rule, remove all the clutter off the deck between
approximately 300mm aft of the foreward end of the cabin top to the
cockpit. The crew will double their speed in tacking, be far less bruised
and stay with you a lot longer. Only the backstay, mainsheet and traveller
and genoa/jib sheets should finally lead to the cockpit.
Mainsail – Always take the head of
the sail right up to the black band, I also always take the foot right out
to the band and only ease it if I know the crew will remember to pull it
on again for the beat. The traveller should be centred for all winds up to
15 knots, very occasionally in very light conditions you may find it
necessary to bring the traveller to windward or in gusty conditions ease
it. Above 15 knots you will need to use the traveller, backstay and
mainsheet. It is absolutely essential that the boat is kept upright, the
J24 keel is very small, any heel induces sideways motion. Finally, do not
overtighten the kicker, I only have the kicker tensioned sufficiently to
prevent the boom flying up if the mainsheet is eased when going to
windward. Clearly mark both the mainsheet and kicker when you are happy
with position as a future reference.
|Photo ©: John Adams|
Big fleet start at the
Genoa – It is crucial that the halliard is marked. The modern
genoas are designed to only have minimum scallops; tension the halliard to
just maintain a straight luff, whatever the conditions, do not over
tension or ever permit the halliard to be winched as that is the quickest
way to ruin the sail for ever. Assuming that your mast is set up correctly
then the genoa cars should be in the forward position at all times. When
you get to the top of the wind range for the sail, ease the sheets a
little, this will open up the leach. My advise is to play with sheet
tensions. Most crews over tension, this sometimes works in calm water but
is very slow in a chop.
Jib – Changing down to jibs usually occurs when the wind
strength is between 18/20 knots depending on the crew weight. Tension the
luff just to remove any scollops. Adjust the jib cars so that the bottom
batten is parallel to the centreline; usually the car on the newer jibs is
very nearly in line with the shrouds.
Spinnaker – In light airs use the lower ring on the mast. Always
try to keep the clews level by adjusting the pole height. Try to keep the
spinnaker luff just curling, this will prevent over sheeting, constantly
ease the sheet to ensure that the luff is on the curling point. Ensure
that the head of the spinnaker flys about 15 cm off the mast to keep the
spinnaker in clear air.
Your first aim is to get the crew weight as close to the maximum 400
Kgs as is possible, unless you know the wind will not get above 5 knots,
racing more than 20 kgs light will give you a significant disadvantage.
Then try to ensure that you all work together as a team. Make sure
there is a proper task for everyone on board, ensure that all the controls
run to their hands not yours. Another point is that very few of us can
race regularly with the same crew, therefore keep everything simple “the
simpler the better”. Make sure all your halliards are marked at the
correct height when the sails have been set to your liking, so that any
crew can return the sail to the same position every time.
Here is a basic breakdown of crew tasks starting at the front:
Foredeck – Call the starting line, call the waves, watchout for
starboard tack boats upwind, carry out all spinnaker pole work,
responsible for the genoa/jib halliard up and down. (We clip the spinnaker
pole to the shroud base upwind and re-attach the sheet to the pole while
still sitting on the rail by running the pole aft before sliding it
forward and clipping onto the shroud base. For those with older poles and
bridles also ensure that they are the right side of the lazy sheet on
Genoa or jib.) Note : The newer poles are much stronger and it is possible
to connect the uphaul to the centre of the pole and use your twinning
lines to hold the pole down.
Mast(No 4) – Clears the weather sheet in the tacks, responsible
for the twinning lines, kicker,outhaul and cunningham, also controls the
spinnaker pole height. Calls the wind both up and down i.e. puffs etc. On
the runs sits with his back to the boom far enough from the mast to allow
the helmsman a sight of the instruments and looks for the wind or other
boats covering your wind.
Spinnaker Trimmer (tactician) - Trim the spinnaker, feed and
douse the spinnaker, ensure the spinnaker and sheets are organised, call
the time at the start, monitor the relative boat speed and ensure messages
get through from back to front or visa versa. Could be tactician if
Cockpit (tactician) - The tactician on my boat. Trims the
genoa/jib and also spinnaker guy in heavy weather, able to discuss options
with both the helm and spinnaker trimmer, look for the shortest, clearest
or quickest route, keep track of the windshifts and finally the main task
is probably to keep errors to the minimum.
The Helmsman - Steers, mainsheet, traveller and backstay, his
main task is to concentrate and keep up the boat speed. At the start
decide where to be, understand the foredeck signals, listen to the
trimmers count down and ensure you are on the front row. Continuously ask
the crew for information, use them all, encourage them all to become
tactically aware at all times. Discourage irrelevant conversation, the
helm will loose concentration and the crew will loose the plot.
Finally, remember this is only a guide. It is more important to try to
understand why all these points put together contribute to finishing at
the top of the fleet. Try to reduce the number of mistakes you may make
during the race. Do not go off on a flyer unless you are really sure it
could be a winner. To conclude, do not forget to thank your crew as
without them you would get nowhere and they may not come with you again
when you need them!
|Photo ©: Mary-Ann Jardine|
Stuart Jardine has been racing J/24s since the mid '80s and racing
dinghies for some 60 years. He has won the J/24 nationals six times, the
2002 championships being the most recent and the XODs four times. He also
won the J/24 Europeans in 1995 and the US Masters Championships (helmsmen
over 55 years of age) three times in the same period. He credits his skill
at setting up and tuning boats to his 25 years of Olympic campaigning,
particularly in the 'International Star'.