Features June 2018 Issue

The Pros and Cons of Chest-high Jacklines

World sailing offers fairly explicit expectations regarding jackstays. And PS offer its own additional advice, including one that recommends jacklines ideally be installed so that a sailor who is clipped in can’t go over the side (see “Jackline Installation Advice,” November 2015). This is not always possible, especially on monohulls. In most cases, he chest-high lifeline on Mahina Tiare will keep above water the head of the person who is overboard.

Pros

• Your tether won’t tangle your feet as you go forward, since it is attached above, not on deck

• You have a line to grab if the boat suddenly lurches or falls off a wave

• The clunking tether shackle along the deck won’t annoy crew members trying to sleep below or damage the boat.

• It’s quick and easy to rig and remove.

• The Aladdin cleat also makes an excellent place to secure flag halyards to

Cons

• Beware of tying into a stern or bow pulpit. The stern pulpits on many cruising boats will fail under less than 1,200 pound loads of load, less than than half the minimum advised for jackline padeyes (4,500 pounds). See "USNA Lifeline Test Reveals Weak Spots," PS September 2012 for the full report. 

• If your upper shrouds are located quite a way inboard, you’ll likely have to go forward on the outside of the high lifeline, which can add risk in some scenarios.

• When clipping in, your center of gravity is higher and you are less stable.

1. We use a trucker’s hitch to tension the lifeline where it attaches to the pushpit stanchions. Virtually all of the load on the lifelines is transferred to these pushpits. Past tests have shown that the railings on some boats are not as strong as they need to be to withstand the dynamic loads of a human bodies hurled against a lifeline (minimum 4,500 pounds), so you will want to make sure yours is up to the task. Backing plates deserve a close look (see “How Big Does a Backing Plate Need to Be?” (August 2016).

2. We use a simple clamp-on Aladdin cleat (aka flag cleat) to guide the lifeline past the shrouds.

3. CS Johnson marine makes a stainless steel guide especially designed for attaching to a shroud.

[Edited 06.20.2018 to reflect vulnerabilities of pulpits.]

Comments (8)

I used 7/16" high mod line because I had some leftovers, too short for any other use. It was far stronger than I needed.Starting from scratch I'd be happy with a 12-plait Dyneema line like Amsteel Blue (any brand). Yes, you could use a covered line, such as Endurabraid, but it is much harder to splice, requires a much larger diameter, and does not provide that much additional chafe protection. But the polyester cover would give UV protection, chafe protection, and a better grip.

At 53' you correctly calculated that you nee something stronger than the World Sailing minimum, and 11,000 pounds gives a nice allowance for UV and wear. I think you are right on course.

Posted by: Drew Frye | June 7, 2018 10:02 PM    Report this comment

I am considering this chest high arrangement for my 58 ft monohull. It would seem that using a high-tech line would be preferable for the lower stretch and higher strength (as you have installed). I think a 7/16" diameter would be good as it is not too small. What type of high tech line would be appropriate for this long run on the big monohull with about 11,000 lbs breaking strength? Appreciate your wisdom, Drew. (I also will have cabin top inboard jacklines as well).

Posted by: Maddox | June 4, 2018 11:46 PM    Report this comment

In PS Sept 2012 there was a summary of US Naval Academy testing that suggested a typical pulpit might hold 1200 pounds, not the required 4500 pounds. While some are probably strong enough, they will the exception. When in doubt, the line should pass through the pulpit end in some manner and angle down to a strong point on the deck. This will also protect a weak pulpit from damage, since these can easily be bent by a single hard fall (it does not take that much to generate a line tension of 1200 pounds).

Yes, gates are a complication. They will need to be very strong.

Yes, a truckers hitch weakens the rope about like a bowline. The weak spot is the first turn. Eye splices and a lashing is the compliant alternative.

I rigged high lines on my boat with clove hitches in place of Aladdin cleats. The line I used was 7/16-inch high tech and very strong, so strength loss didn't matter. My reason was that I had sheets inside the shrouds that could snag on the cleats. Every boat is different. (I also had jacklines on the cabin top, some distance inboard. The combination worked well.)

Posted by: Drew Frye | June 4, 2018 9:01 PM    Report this comment

Just wondering about loads. I read somewhere that John used pre-stretched polyester line. 8mm 8-plait pre-stretched line from Marlow has a breaking strength of 5,192 lbs - 3/8" is the recommended line for the CS Johnson fitting. Does the trucker's hitch essentially cut the breaking strength in half? (Always read that knots reduce strength 50%) I thought the goal of a jackline is to have 4500 lbs of strength.

I have seen solutions that go with an eye splice for strength and multiple loops/turns of small diameter amasteel to tighten and fasten the jackline to the termination point. Thoughts on this approach?

Posted by: Maddox | June 4, 2018 10:52 AM    Report this comment

How does it work with gates?

Posted by: GEP | June 3, 2018 2:54 PM    Report this comment

How does it work with gates?

Posted by: GEP | June 3, 2018 2:54 PM    Report this comment

My first thought: "That's a bad idea!"
Then I thought about it and looked and thought.
I'm really really not interested in a lifeline that drags me in the water beside the boat: I'll die!
I can tell that I'll rig high jacklines on my boat as soon as I can. I'll put up with the disadvantages (which are Small).

Posted by: ozdigennaro | May 28, 2018 7:29 PM    Report this comment

It would be great to see pictures of an actual installation. Where does the line begin and end? What holds it chest high? The shrouds? If its attached to the pushpit and pulpit and held to chest level at the shrouds then it is only chest high toward the middle. Is that right? If the shrouds are inboard you then must duck under the line to walk forward, right?

Posted by: Triples66 | May 26, 2018 1:07 PM    Report this comment

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