Lazy jacks guidelines?

[sanibel sailor]

Thinking about installing lazy jacks and seeking design input. Foot of sail is 13', full battens. Single spreader rig, was thinking about mast attachment point just above spreaders with 3 legs on boom.

Are there any design guidelines or rules of thumb? I did a search and got a gazillion threads, none of first hundred seemed helpful.

[Bill Seal]

I have the same question, 13' boom, 32' hoist, single spreader. I plan on hooking them out of the way except when dropping the main.

[zeehag]

lazy jacks are useless when not in place when sailing. you have a need to dump sail., oopsy why even install em if not gonna use em.

[stormalong]

Lazy jacks are very useful and I like mine out of the way when not in use. The only time they are deployed is when dropping the main. A full batten sail will be easier to handle so I expect three lines should be adequate. For shorter battens like mine four lines are better. On my double spreader rig the top block is well above the lower spreader. I also have some hooks on the spreaders to keep the lazy jacks from banging on the mast. I hate the noise of slapping lines.

I use some tiny Ronstan blocks at the slip joints to make stowage/deployment easier. They are rated for a 300 pound load and are all plastic except the axle pin.

[Sailor 99]

Originally Posted by sanibel sailor

Thinking about installing lazy jacks and seeking design input. Foot of sail is 13', full battens. Single spreader rig, was thinking about mast attachment point just above spreaders with 3 legs on boom.

Are there any design guidelines or rules of thumb? I did a search and got a gazillion threads, none of first hundred seemed helpful.

Its nice if you make a stack pak so that you leave the lazy jacks out but loosened off and then if you have to reef the excess sail just sits in the stack pak. You don't need to tie it off.



Also means that when you are done you just run the zipper up and walk away

[sanibel sailor]

Don't care for the look, windage, or complexity of the stack pack system.

[Suijin]

My lazy jacks terminate @ 4-5’ above the spreaders on a 55’ mast. Three attachment points on the boom. They are 1/4” double braid running through @ 1.5” stainless circles, and can be stowed at the mast. Full batten heavy offshore sail.

As a single hander life would be much more difficult without them. I can drop the main, throw one sail tie on it if the wind is up, and sort it out later. A huge asset.

[sv.antea]

I have recently redone my lazy jacks. On my30' boat with full batten main, two things worked out really well: Using yellow ZingIt 2.2mm dyneema string and handful of tiny Ronstan Kite Blocks. When racing, I stow the lazy jacks to a clip by the goose neck, when cruising I leave them deployed. The string is incredibly strong and slippery, so there is little windage. Having a easy way to stow them is important, since it is hard to re-hoist the main with them up. At least one side has to be gathered forward for that. The only hassle is what to do with the excess string when the lazy-jacks are deployed. Tried different ways, but so far just coiling and securing the hunk somehow works. The good thing is that the ZingIt string doesn't tend to tangle.
With full battens and a goodly roach, it is advisable to carry the three branches well aft. The luff of the main is after all well attached to the sailtrack, so the forward part of the main generally behaves.

[boatnerd]

If your actively cruising theyre very useful along with a preventer system. Especially dealing with a big heavy main. Its good if theyre retractable and easily adjusted from the mast. I dont think blocks are necessay(like on store bought ones) where the lines split but instead just use an eyesplice and wrap splice with some sail repair tape. Less stuff to flog around aloft. When figuring out where to postion your lines watch out for battens when raising sail.

[Suijin]

Blocks are not required in my opinion and are in fact bad: they chafe the sail when deployed or the mast when stowed unless you put leathers on them. The jacks are never under any load so you don’t need them anyway.

[mikeo16]

Look at the installation instructions for the Harken LazyJacks available online to build your own. You will definitely need 3 legs (contrary to the Harken guidance)

[Argyle38]

I had seen a design of retractable lazy jacks well before I bought Argyle. Once I had the boat and wanted to install them, I couldn't find any reference to the design anywhere. I finally found one blogger who had a very small sketch of his setup so I went with that. Here's a sketch of that lazy jack system overlaid on a drawing of a Downeast 38 from an old brochure scan.




I've been using this system for years now and love it. The lazy jacks retract completely along the boom and mast. That makes it so all the drawbacks from lazy jacks, chafing, airflow, difficulty in lowering the sail in a hurry, etc., are gone. I also don't have to get a special sail cover, since once the sail is tied up, the lazy jacks are retracted so it's just a normal sail, flaked on the boom.

The system is just three separate lines, per side, and three stainless rings that the lines either pass through or attached to, and some mast and boom hardware.

The red line in the sketch is the control line. There is a cheek block on the mast, here shown about 1.5-2' under the spreaders, I think mine ended up a little closer. The line is hard attached (not passed through) a SS ring where the two angled portions meet. The green line is attached to the boom, then passes through that same SS ring, then is attached to the middle SS ring. The blue line, identically, is attached to the boom some ways forward from the green, is passed through the middle ring and attaches to the lower ring. The magenta line attaches to the boom, passes through the lower ring and attaches to the boom again, so it just loops through the ring. The red control line is secured at the bottom of the mast with two cam cleats, one for the hoisting side of the line and one for the lowering side.

To lower the lazy jacks, the hoisting side of the red line is taken off its cleat and the lowering side is pulled. The green, blue and magenta lines are tacked to the boom, and their lengths selected such that when the lower part of the red line is pulled tight, all three lines lay along the boom under tension with the three SS rings right next to each other at the gooseneck.

It took some tweaking during installation to get all the lengths right, but it wasn't hard at all. The only drawback I've seen is with my low aspect main, the back 1/3 or the sail sometimes flops over one side or the other when lowering the sail, and the very aft end of the sail is not supported.

[roverhi]

I set mine up like these Nautos Lazy Jack Systems. https://images.search.yahoo.com/sear...g&action=click The first line runs from a cleat on the mast up the mast to the cheek blocks and down terminating in a ring. Another line that goes to a padeye on the boom up through the ring and down terminating in another ring. Run a line from padeye on boom up through that ring and back down to a padeye near the leach end of the sail. Have cheek blocks on the mast but used brass rings that I picked up cheap on Ebay for the rest of the setup. Used 1/4" iine on the Pearson 35 and 3/16" on the Sabre 28.

The cheek blocks on the mast need to be high up, both of mine are midway between spreader and mast head. Higher mounting might even be better. If the cheek blocks are not mounted up high the acute angle of the lazy jacks pulls in toward the mast and doesn't capture the aft end of the sail when it's dropped

The outboard padeye is about 2'-3' from the end of the sail and then
the other two are spaced evenly along the mast at about 1/3rd interval of the remaining distance to the gooseneck. If the outboard padeye is not near the leach end of the sail it will allow the lazy jacks to sag in towards the mast and do a lousy job of capturing the sail.

I've tried different arrangements to try and decrease the sag in toward the mast. If the sag is too great it allows the aft end of the sail to escape. The problem with other arrangements of blocks, etc didn't allow me to stow the lazy jacks at the mast which I do when not in use. Simply pull them forward and hook them under the Lazy Jack's cleat on the mast. Don't like the lazy jacks chafing on the sail and interfering with air flow over the sail when not being used to cradle the sail. Also a real PITA to raise the sail without the LJ's hanging up on the battens. About the only way I've done it is motoring with lazy sharp accuracy directly into the wind. Something that I've almost never had a helmsman capable of doing especially when I'm doing it solo.

Apparently you can solve the hang up on hoisting issue by running the LJ's to the spreaders. Really really don't like that idea as you have all those lines waving out there in the wind. You also have the acute angle gathering issue of the aft end of the sail.
https://images.search.yahoo.com/sear...g&action=click

[Privilege]

Another consideration when designing your system, especially on a fully battened mainsail, is how far towards the rear of the boom to place the last part of the lazy jacks. On my boat, when I raise the main, the slightest bit of side-wind pushes the sail enough to ensure that the end of the batten goes under the jack and catches. If you can get away with it, depending on your set up, have the last jack so that it doesn't go further aft than the last few battens.

[Quebramar]

Originally Posted by Privilege

If you can get away with it, depending on your set up, have the last jack so that it doesn't go further aft than the last few battens.

My experience is the opposite. I had 3-leg LJs splitting the boom in 4 approx equal parts. No stack pack. It was really difficult to get the longer full battens to stay on the boom. , as the aft leg was not aft enough and slope was not vertical enough.

When changing the main I ordered a stack pack sustained by 4-leg LJs, so I could better cover the aft end of the battens.

Attachment up is to the spreaders so as to keep the opening between both wide enough to allow the sail some space and avoid batten being trapped. I keep the LJs up, this requires some attention to keep the sail head to the wind when hoisting but no big deal. I could lower the LJs if needed, but that happens at the mast.

Leg attachment to the boom is 2 by 2 in order to enable easy fine tuning of the tension in each leg: legs 1 & 3 join with their neighbouring ones (2 & 4 respectively) who in turn join below the block on the spreader. Took me some time for trial and error but now it works fine 100% of the time.