Lazy jacks guidelines?

[Frankly]

Have retractable lazy jacks on two different sailing craft (35 sailing years). Full batten main, cannot imagine a simpler system for containing the main on the way down.

Cheek block just under the spreaders, control line down the mast with a small nylon cleat on the mast at boom level. They go up for the few minutes of lowering/ securing the main, rest of the time stowed along the boom and mast.

For years used small blocks in the end of the jack lines, just ordered some of the tiny Ronstan aluminum blocks/ rings and some Dyneema. Going to be "mo better" going fwd. Have to play with the jack lengths to get the catching right, and have a couple of lines to cap shrouds to pull them from clapping on the mast.

Frankly

[Swizzle Stick]

I know I'm resurrecting an old thread, but I just re-rigged my lazy jacks so I thought I'd share how I did it.

I had to remove my sail bag for some running repairs and when I put it back on I noticed the main sail didn't fall as nicely into the sail bag. I forgot to write down how long each lazy jack rope was before I took the bag off so I guess I didn't put it back the same as it was.

In any event, my lazy jack ropes were a bit tired - and short - so I decided to re-rig the system with newer, longer ropes.

I've read about others using high strength non-stretch rope like Dyneema, but I figured all the tie off points are accessible from deck level and it will take two minutes to untie and retie a rope if it stretches a bit.

I just used 4mm synthetic rope from the hardware store for the droppers - 300kg breaking strain, knots easily, A$22 for 60 metres.

The halyards are made out of "proper" rope. I kept them.

My sail bag has four attachment points. I reckoned running the halyard as high as practical up the mast would provide the best angle of pull - and largest net to catch the sail - so I did some measurements.

I pulled a thin piece of rope up the mast using a spinnaker halyard to measure the height of the lazy jack halyards above the top of the boom - 6.6 metres.

Then I measured the distance along the boom between the back of the mast and each of the four sail bag connection points.

Finally, I measured the height of each tie off point above the boom.

Then it was time to select the length of each rope.

I took a piece of A3 paper and drew a scaled diagram. I drew a straight line from the furthest attachment point (4.8m back from the mast) to the halyard attachment point (6.6m above the boom).

I placed the three blocks (per side) directly above each bag attachment point and drew vertical lines down.

I measured each rope off the scaled diagram to determine the effective length of each rope, then added 0.5m tie-off allowance before cutting the ropes.

If you're mathematically inclined, you can use trigonometry to check your scale measurements. Mine were pretty close so I was comfortable I got it right.

My three ropes needed to have 6.75m, 5.5m and 4.4m effective lengths. I took a spare piece of rope, cut it to 6.75m and tied electrical tape at 5.5m and 4.4m to use as measuring rope.

I pulled the old system down, untied it, rigged up the new one, pulled it up and voila - it worked.

Of course, the four segment line from the rear sail bag attachment point to the halyard attachment point can never be completely straight unless the lines are infinitely tight. Doesn't matter! The lines naturally drop a little and move towards the mast a little to account for this quirk of physics.

Photos of the final arrangement and my scruffy sketch (with trig calcs) are attached. All dimensions are in millimetres and metres. I'm sure trigonometry and scaled diagrams also work in feet, inches and bushells per statute kip .

I hope this helps.

[Halcon2]

Hello Argyle I’m researching potential lazy jack systems and came across your post I recently purchased a Hunter 28.5 1988. I like the idea of stowing and deploying as needed. If you have any pictures of the hardware installed on the boom and mast I would appreciate it thank you

[GSpencerCat30]

I love my lazyjacks on my Catalina 30. Really nice when single handing.
I put blocks on my mast and cleats at the base of the mast so that I could drop the lines while racing. I use a bungie cord to keep the lines tight to the mast while sailing.

[Stu Jackson]

Lazy Jack Trick
Many folks complain about full battens getting caught up when raising the mainsail. They then spend a lot of time moving BOTH sides of the lazy jacks to the mast.

We developed an easier way with our lazy jacks.

We have a small cleat on the forward starboard side of the boom. When we put the halyard on the headboard, we move ONLY the starboard side of the lazy jacks forward and snug them under the forward side of the horn of this cleat.

Then, when we raise the mainsail, instead of going exactly head to wind, we bear off a tad to starboard so the wind is coming from the port side of the bow.

We then raise the mainsail and it doesn't get hooked on the lazy jacks even though the port side jacks are still there.

Been working for 20 years.

Yes, we have to go forward again to unhook the starboard lazy jack for dousing the sail if I forget to do it right when the main is raised, but there's never any hurry. The drill is: after the main is raised, I unhook that starboard lazy jack, so they're both ready to go when we drop the sails at the end of the day.

So, for those of you with lazy jacks, consider doing only one side.

Your boat, your choice.



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