Tuning your J/24 for Speed
>> Download the North J/24 Tuning Guide (San Diego)
>> Download the North J/24 Tuning Guide (Newport)
>> Video presentations on mast tuning and sail trim
What's the recommended tension for the backstay?
With regards to the backstay we thought having it off to
measure the forestay would make it easier to get a method where all boats could
be tuned the same. You are right that just hooking it up and even trimming the
main effects how much the forestay will sag...
that in mind we suggest (this is in the tuning guide) that the tension on the
backstay bridle always be adjusted so the blocks sit about 8" below the triangle that joins everything together.. So
each time you tighten or loosen the shrouds for a change in wind velocity you
will need to do the same for the backstay bridle.
Can you give me some hints on how to go faster on a J24?
It is really important to sail at max weight 882 lbs. In anything
above 10 kts, that extra weight is noticeable in terms of upwind
performance. At the top of the fleet, we try really hard to make sure
we are max crew weight.
Changing gears in the J24 is huge! The skipper has a lot on
his plate. The top guys make the skipper responsible for the backstay,
traveler, mainsheet, Genoa trim and steering the boat. Let me try to
explain how this works. A nice steady breeze makes it a lot easier
obviously. In the steady breeze you can kind of get things set up and
just rumble. In a puffy breeze, there is a constant adjustment of the
Puff hits…crew eases genoa, skipper eases traveler.
Puff begins to ease up,skipper pulls traveler back up, cleats it. Then moves quickly to the winch handle and cranks in the genoa.
Repeat the above sequence with each new puff.
There are different variations of this depending on-strength of the puffs. If the puffs are very strong…vang sheeting-becomes a little more effective. A super tight vang and using the process above, but instead of easing traveler down, you’re easing mainsheet.
The backstay should be set as close to a happy-medium as possible, but every now and then it should be adjusted based on the overall trend of the breeze. I like to have it eased in the light spots as much as possible, as long as you can get enough back on before the next big puff hits.
It would be nice to have three hands. Trust me it is not easy…it takes a lot of practice.
You want to start by getting your boom at centerline. You
accomplish this with mainsheet tension and traveler. The mainsheet
tension controls the amount of twist in the sail and leech tension. In
light air or light spots, you want twist (and the top leech tell tale
flying)…so softer mainsheet tension and a higher traveler to keep boom
at centerline. A twisty main is also good for accelerating or for bow
down modes. You want nice twist in your main after a tack to help the
boat get back up to speed quickly. In medium breeze, you want a tighter
mainsheet to close the leech a little for better pointing. You have to
ease traveler down to keep boom at centerline if you pull on mainsheet
tension. The only time you let the boom go below centerline and go
traveler down is when you really need to de-power and keep the boat flat.
Even before a lot of traveler down, I am usually putting on some
backstay to de-power.
The backstay has a few rules of thumb. Take some off for
more power and pull some on to de-power. If your main starts to invert
and flog, you should ease some backstay to get flow over the sails going
again. Backstay is more of a macro adjustment unless it is really
puffy, then you are constantly easing it off in the light spots. Also,
if you are ever overstood in breeze and need to crack off, put lots of
backstay on. If you need to point higher in a short distance like if
you understood the windward mark, take backstay off.
The Genoa trimming by the skipper is key. Basically the
skipper sits right next to the winch that has a winch handle in place.
In a puff the trimmer, who is hiking out all the way, will ease the
genoa in anticipation of the puff, not letting the boat heal over (we’re
talking like a foot or more of ease at times), and then the skipper
winds the winch handle to crank the sail back in before the boat heals
to windward. This takes some practice, but once you get it, it’s huge.
Never let the boat heal to leeward. Anytime the boat is healing it is
sliding sideways a lot faster than you think. When a 30 knot puff
hits, you actually have better VMG if your boat stops dead in the water
and remains flat, than if you heal over, go forward but slide sideways.
The boat that stopped dead in the water will actually be closer to the
windward mark after the exchange.
How often do we get new sails? The Genoa obviously takes the
biggest beating. After only a couple heavy air regattas you will be
able to notice a performance difference between a new and used sail.
It’s not only the beating the sail takes against the mast in tacks, but
also the crew stuffing it up on the bow during downwind sailing. You
might not like to hear this but we make sure we have a new Genoa for
every big event.
Quantum is pushing a material called AirX. What is you opinion and what type of material is the North Spinnaker made out of.
We make our sail out of a material called Superkote. Both, the Superkote
and the AIRX 650 which Quantum uses weight very close to the minimum
allowed weight of 42 grams per square meter. I have used AIRX on a
J/24 spinnakers. My conclusion is that it makes a good sail but one
that is best in flat water and a good breeze. The Superkote is actually a
little softer which makes the sail more forgiving in any of waves and
lighter winds. Superkote also seems to last a little longer as it relies
more on the weave of the cloth for strength rather than a surface
coating. / Answer by Chris Snow
I've been told J24s roll tack easy enough. Using techniques I adapted from dingy racing and a basic knowledge of hydrodynamics, I tested this theory and couldn't get it to roll over. Is there a better technique for fixed keels that i don't know about?
Roll facing out and push down on the windward
life line. Start from the middle of the boat and do it all together.
With four people rolling you should be able to get the windward rail all
the way down to the water, once it is flatten the boat slowly and you
will get a nice squirt forward.
What is your feeling about Newport vs San Diego cut. I sail in the Inland NW.
Sailing on a lake where the wind is shifty I would choose the San Diego designs. This sail is fuller in general especially in the middle which
makes it more forgiving to trim in variable and shifty conditions.
sail can take quite a curl before it becomes unstable. The Newport
better in open water straight line sailing.
What is your opinion about having multi color sails. I read somewhere that it was better to have one color due to the stretch in the panels over time. Is this a big issue?
We highly suggest having the head and clews of the sail each a
solid color. Also I would try to have these areas lighter colored if
possible. This way the top and bottom of the sail is made from the
lot of cloth and it will stretch relatively evenly over the life of
sail. Also making the sail with lighter cloth in the top and bottom
insure that you are getting a sail made with Grade A woven cloth. With
darker colors flaws can be hidden and even though all the cloth is
tested by the maker and us this generally seems a safer bet.
The tuning guides tell me about which ring to fly the pole from but as the wind builds I find that the floating tack sometimes wants to fly quite high. The question is once you have got the pole to horizontal, do you keep raising the pole to keep the kite level or do you use the barber hauler (twinning lines) to keep the floating tack down to the pole tack. Does water conditions affect your thinking on this?
Generally the J/24 likes the pole on the low side so while
we try to keep the clews level we also work on keeping the pole end
little lower than the free flying end. We generally twing the pole
down enough that the pole will sit right up at the tack of the spinnaker
at all times.
Generally do not use the leeward twing on a J/24. The boom acts
as plently of a twing when needed.
What's the difference between the San Diego and Newport sails?
The mainsails ARE very similar. I know the San Diego sails well and
have helped to develop these sails. About two years ago we made the
main significantly flatter. The reason was that the J/24 likes the main
trimmed really hard and for sure a flatter main can be trimmed harder
before it stalls. Both mains are quite forgiving.
The San Diego genoa is touch flatter than the Newport genoa (The Newport
main is flatter than the San Diego so needs a fuller genoa to go with
it). We have found that the sail is really fast in the upper end conditions
with the genoa where sailing the boat and keeping it flat is harder. In fact
the sail was so good in a big breeze that we just made the top of the
sail a little fuller to make it easier to keep the boat going in lighter
When to move the mast butt position?
There is no real reason to have to change
the mast butt position once you find the proper location. Here we use
a Loos Model B tension gauge and with the lowers on 21 and the uppers
on 24 we measure the headstay tension with the backstay completely disconnected.
The headstay will be loose and the tip of the gauge should be about
30 mm from the headstay if you have everything set up right. You will
also have about 3 to 4 cm of prebend at this point. The only time I
have seen adjsuting the butt while racing work is when it is really
blowing hard (25 knots plus) and then moving it forward just a bit MIGHT
How to ease and trim the main and jib together smoothly? Well..easing isn't hard but since I grind the winch for the jib/genoa and pull in the main they don't come in together, it's always one or the other first. Both together is obviously better but I'm not sure how to do it. Do you have the cockpit guy grind in the jib himself and only worry about the main when both are eased or do I just try to do both myself. How do you do it?
You are talking about when you are cross
sheeting the genoa and jib. Basically I think the best thing to do is
if you just ease the jib a inch or two, you need to grind the sail back
in a keep the cockpit guy hiking out.
Yes the sail will not be trimmed in exactly
the same but I think this is less disruptive. If you have the ease the
jib a lot (like when ducking) have the cockpit guy turn around and grind
and tail the sheet him/herself. This way you can concentrate on the
The balance between the two sails on
a boat like a J with the a small keel is important. Keep playing the
sails in concert with one another.
How can I get my J24 to point higher?
Generally the reason a J/24 does not point (or sail as
close to the wind as the boats around it is because the boat is not
developing enough weather helm. The boat needs a small amount of weather
helm to be able to always sail as close to the wind as possible.
The first thing to do is to recheck your boat against
the tuning guide to make sure you have followed everything correctly.
If this is so then I like to go out sailing with the rig tuned properly
for the wind and take a close look at the mainsail set up. Usually what
you will find in these cases is that the lower part of the main to too
flat relative to the top of the sail. In general the sail should have
a nice smooth shape from top to bottom, often in cases where the boat
is not pointing well the bottom of the main will be very flat right
off of the mast indicating that we need to move the mast butt forward.
Start by moving it ¼" and see if that makes a difference,
it should make the lower part of the mast a lot straighter and give
you more helm and height!
My J/24 sails nice and high but I can't get it to go as fast as the other boats through the water. What can I do?
You basically have the opposite problem of the folks in
the question above. There are times in race where tactically you want
to " put the bow down" and just go fast regardless of height.
If your boat won't do this you are handicapped a bit. The problem is
that your lower mast is too straight which makes the main too full and
causes you too develop an excess amount of weather helm. Every time
you try to sail the boat low and fast the boat heels too much and develops
more weather helm. Move the mast butt back ¼" to put in
more lower bend, recheck your shroud tensions and you should be all
Should I use the upper or lower ring on the mast for the spinnaker pole?
With the Newport spinnaker we use the lower ring until
about 15 knots of wind. For the San Diego spinnaker use the lower ring
until about 10 knots.
When I sail in heavy air with the jib I can't get the jib halyard tight enough to remove all the wrinkles in the luff of the sail?
Above 20 knots you want the luff of the class jib smooth
with no wrinkles. To get the halyard tight enough sail downwind before
the start with the backstay off and have two crew pull up the halyard.
This should get it tight enough. Be sure to get the jib up BEFORE you
tighten the backstay at the leeward mark.
How important is the J/24 spreader angle adjustment? This seems to be hard to get right.
The spreader angle is hard to get right but it is worth
the effort. The spreader angle affects how "stiff" the mast
will be in the boat. Angle the spreaders forward and the mast gets stiffer,
sweep back and the mast gets more flexible. This is important because
as we tighten the backstay we need a certain amount of stiffness in
the mast so the headstay will get tighter and flatten the genoa as the
If you have a older mast with "male" stainless
steel fittings coming off the mast we suggest either retrofitting to
a thrubar set up or using the Allis Racing style spreader adjusters.
With a newer mast you may need to bend your thru bar to get the right
angle (see your local machine shop).
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