Just a Little Further

The Blue View – Lazy Jacks

As my years start to catch up with me, I am beginning to realize that making Nine of Cups easier to handle by “senior sailors” is a worthwhile objective. Our lazy jacks are a case in point. When we first started cruising, I didn’t think twice about going forward in 30+ knots of wind to manhandle the main and secure it in place with sail ties while Marcie kept Cups pointing into the wind for the ten or so minutes the process took. Holding on dearly with one hand, as the roll of the boat tried to fling me overboard,was just part of the adventure. Now, as I most assuredly fall into the “senior” category, I can certainly see the advantages to such things as a lazy jack system.

Lazy jacks are a network of lines that are rigged to contain the mainsail when it is lowered. These lines run from a point high up on the mast to several points along the boom. As the mainsail is lowered, these lines make a cradle of sorts to keep the main from drooping down onto the deck. Sailors were once referred to as tars, and British sailors were called “jack tars” because of the union jack on the British flag. Legend has it that these types of sail taming lines were first employed by the British navy, and since the jack tars no longer had to work as hard as other tars to lower or reef the sails, these systems became known as “lazy jacks”.

I looked at what a multitude of other cruising boats had done. There seemed to be an even mix of commercially purchased systems and custom, owner built systems. I first looked into purchasing one of the commercially available lazy jack systems. Most were undersized for our size vessel, many were more complicated than I wanted, and all were more expensive than if I did it myself. After talking to several other yachties who had built their own systems, I decided to do the same.

The lazy jack system we devised for Cups is quite simple. It is retracted out of the way for most of its life. It is only in place when it is time to drop the main, and it remains in place only until we have the opportunity to secure the main with sail ties. We can only retract or engage the system at the mast, which means one of us must leave the cockpit when we drop the main. Our main has partial battens and simple plastic sail slides, and since it does not always drop all the way without a bit of help, one of us is usually at the mast anyway, so this is a minor inconvenience.


figure 1


Figure 1 shows the basics of the starboard side of our system. The port side is the mirror image. Each side consists of several lengths of line (color coded in the figure for clarification), blocks, thimbles, eye straps, and one cleat. The system we implemented on Cups uses four line segments as shown. The foot of our mainsail is 15′ 8”(4.8m). If the foot of your main is significantly shorter, you may only need three line segments. Likewise a longer foot may require an additional line segment.

The first decision is where the upper block is to be attached. Considerable vertical height is needed if the system is going to contain the sail. On a double spreader rig, the upper spreader is about the right height, and a small block can be attached to the underside of both upper spreaders with eye straps. The eye straps should be located aft of the center line of each spreader, and about 9” (23 cm) from the mast, although the distance is not all that critical.

For a single spreader rig, a cheek block should be attached to both sides of the mast somewhere around 70%-75% of the mast height. If the base of the cheek block is stainless and the mast is aluminum, the two metals should be insulated from each other to prevent the inevitable corrosion. The paint or anodizing on the mast is not sufficient. I keep a small roll of the heavy clear plastic used for dodger windows as insulating material. It can be cut to size with scissors and I use a small hole punch to make holes for the mounting screws.

The mast or spreader should be drilled and tapped, and the eye straps or cheek blocks mounted with stainless machine screws. The screws should be gooped-up with an anti-corrosion compound like lanacote or TefGel, and the cheek block or eye strap should be insulated from the aluminum surface.

To determine how much line is needed, I started with the hoist (the blue line in Figure 1). The line needed is about twice the “H” dimension plus about 5 feet to allow room for an eye splice and enough line to cleat off the end. On Nine of Cups, the height of the block from the boom was 37′ (11.4m), so the hoist length was 2*37 +5 = 79′, which I rounded to 80′ (24.6m). Each of the other line segments were about ¼ of this length, or 20′, plus about 3 feet to allow for eye splices for a total of 23′ (7m) each. So the total line for the starboard side was 80’+23’+23’+23′ = 149′ (45.8m). The same amount of line was needed for the port side, for a total of 298′ (91.6m). I used 1/4” (6mm) polyester double braid. Cut each line to length and whip one end.

Next the cleats are mounted on the mast. The best location is near the end of the boom, but if there are other lines or hardware interfering with this location, locate them elsewhere. The holes should be drilled and tapped as for the blocks, and the mounting screws and cleats insulated from the aluminum mast.

It took me three iterations to get the combination of blocks and thimbles right. On the first iteration of the lazy jacks, I spliced stainless thimbles onto the ends of the lines instead of using blocks. The crews of several cruising boats I talked with used this approach and were satisfied with it. It didn’t work well on Cups. I think the reason was that we used four line segments, and while thimbles may have worked on a three-segment system, there was too much friction on a four-segment system to draw the aftmost lines tight. On the next iteration, I used small blocks on the end of each line segment, but this approach also had problems. It deployed and retracted very well, but the upper blocks hit against the mast. After the first good blow with them in place, not only were they noisy, but they removed an amazing amount of paint from the mast. On the third and final iteration, I used stainless thimbles on the highest connections and small blocks on the other three, and this has worked well.

As a starting point, I used equal spacings along the boom for the eye strap positions. Then I temporarily attached the ends of the lines to the boom at the measured eye strap locations. I pulled the lines taut and hoisted the mainsail and let it drop a few times to make sure the lazy jacks would contain the sail without too much spilling out. I needed to move the eye straps to get it right, and when I was finally happy with the positioning, I remarked their locations with tape.


figure 2


The next adjustment is the height of each of the blocks. I retracted the starboard lazy jacks and hooked the lines under the reefing hook at the forward end of the boom as shown in Figure 2. Then I pulled the hoist line tight, cleated it off, and made sure the blocks and thimble did not interfere with anything. I adjusted the lengths of the lines as necessary. Then I adjusted the port side lines to the same lengths.

I removed the lines and tape from the boom, then drilled and tapped holes for the eye straps and attached them with stainless machine screws. I used plenty of anti-corrosion compound on each screw. After putting the end of each line through its eye strap, I tied a stopper knot to keep it in place. I deployed it, retracted it, and raised and lowered the mainsail a couple of times to make sure it worked well.

Now, after at least three iterations and several more tweaks, I am happy with the system. When we are ready to drop the main, one or both of us goes forward to deploy the lazy jacks. This takes only a minute or two. Then Marcie turns Cups into the wind and lets the main halyard go. The mainsail usually comes down on its own, but frequently needs a little help in the form of a tug or two. The sail stays contained in the lazy jacks until we have anchored. Then I secure it with sail ties, retract the lazy jacks and put the sailcover on. Much easier for this senior sailor.

I have a longer, more detailed version of how we made our own lazy jacks which we will be happy to send along on request.

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