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This J/24 Tuning Guide was written to help you get the best performance 

from your boat. It represents years of sailing successes in the class as well as 

computer analysis of the sail plan. The measurements and settings included 

in this tuning guide are the fastest for your J/24 with UK Sailmakers sails.
Since crew, wind and sailing conditions vary, you may find different settings 

that are best for you; however, by following these instructions you can be 

confident that you are well set up to win the next regatta. 
Always remember that besides having a prepared boat, nothing replaces 

time on the water.

PREPARATION

Hull:

 The hull of a J/24 

requires little attention 

once it is faired. You 

are not going as fast as 

the boat’s capability if 

you don’t have a faired 

bottom. Wet sand the 

bottom with 400 grit 

sand paper, 600 grit for 

the keel and then clean 

it with soap before each 

regatta. If you moor 

your boat you’ll need a 

different bottom finish.

Keel:

 One of the most 

critical factors in speed 

gains is keel shape. 

Move the keel as far 

forwards as the rules 

allow and fair to mini-

mum thickness. A well 

faired keel will provide 

more lift, better pointing 

upwind and less drag off 

the wind. 

Rudder:

 Keep it clean 

as possible. Repair all 

damage immediately, 

especially on the trailing 

edge.

Rig:

 There are several things to do before step-

ping the mast. 

• 

Remove the spare genoa halyard

• 

Remove the running light and wiring. Cover 

the holes with sail number martial or Teflon 

tape. 

• 

Cut mast butt off to the class minimum 

length. (Ask your class measurer.)

• 

Install a small size Windex wind indicator on 

the back of the masthead crane.

• 

Exit the genoa halyard to the lowest slot on 

the starboard side of the mast. Mount two 

Harken Camcleats (one below the other) 

just below the cutout. Pass the halyard to 

a small ratchet block on the deck. Exit the 

main halyard to the lowest slot on the port 

side.

• 

Exit the spinnaker halyard eight feet above 

deck level and mount a camcleat just below 

the cutout. 

• 

Exit the topping lift to the upper slot on the 

port side.

• 

Take off both ends of the boom and replace the outhaul system using a 6:1 

Harken block system with 3/16” pre-stretch line. 

• 

Before stepping the mast, clean it and give it two coats of silicone based  

marine wax. 

UK SAILMAKERS J/24 TUNING GUIDE

INSIDE THIS GUIDE
Preparation 

1

Weight 2
Tuning the Rig 

2

Fine-tuning the Rig 

3

Shroud Tension Chart 

3

Sail Trim 

4

Deck Layout 

5

Go Fast Tips 

5

Summary of Contents for J/24

Page 1: ... keel will provide more lift better pointing upwind and less drag off the wind Rudder Keep it clean as possible Repair all damage immediately especially on the trailing edge Rig There are several things to do before step ping the mast Remove the spare genoa halyard Remove the running light and wiring Cover the holes with sail number martial or Teflon tape Cut mast butt off to the class minimum len...

Page 2: ...e shrouds at the spreader tips Then measure from the middle of the string to the aft face of the mast The spreaders are at the right angle when the measure ment is 165mm Tape the spreader ends to protect the spinnaker and genoa After Stepping the Mast Butt Position The front face of the mast should be 2845mm from the bottom bolt of the bow stem fitting looking forward while in side the boat to the...

Page 3: ...in winds from 8 up to 16 you can trim the genoa one inch closer than the numbers on the above chart Tip Write this chart on the deck with the number of turns you need to move from one tension setting to the next Loos Tension Gauge Model B FINE TUNING THE RIG Your mainsail is designed to perform in 10 knots of wind with 2 1 4 of pre bend In heavy air bend can be achieved through backstay tension wh...

Page 4: ...hances are one of these items has occurred Over tensioned the genoa sheet Over tensioned the genoa luff A loose mainsail leech Jib Trim Once the wind picks up over 19 knots you will need to change to the little jib Set the lead so that the foot of the sail touches the foot of the pulpit and the leech reamins 2 insde the spreader tip If the wind goes over 25 knots move the lead back 1 to tighten th...

Page 5: ...der Bring the tack the corner of the sail at the pole lower than the free flying clew NEVER allow the tack Sail at maximum crew weight Sail the boat as flat as possible Do not pinch Set the shroud tension for the wind you are expecting in the first part of the race When in doubt select the more powerful option because it is easy to depower the boat Downwind heel the boat to wind ward Downwind use ...

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