Jacklines: Materials, Fabrication and Installation

jhhomd1-9291617Up to this point in this Person Overboard Prevention Online Book we have sorted out where jacklines should be installed (on the centreline of the boat) and how they should be used (continuous attachment).

Now I'm going to look at what materials we used to make our jacklines on Morgan's Cloud, how we installed them, and the reasons behind those decisions.

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Dick Stevenson

Hi John,
A really nice piece of work!
I find it incredibly sad that Hathaway, Reiser & Raymond has closed their doors. They were impressively innovative over their years of providing rigging/sailing advice and expertise to East Coast sailors and always willing to help figure out great solutions to the kinds of problems we all bump into regularly.
One of their products/designs (recently well reviewed in Practical Sailor) is the Galerider Drogue, an alternative to the AAC preferred Jordan Series Drogue. Those looking for the Galerider can still find it being made by Seafarer Canvas and Interiors who has bought/taken over some of HRR’s business.
My best, Dick Stevenson, s/v Alchemy

Drew Frye

The Galerider is perhaps the best choice for emergency steering–very smooth, not too much drag. I jammed a rudder by hitting a submerged log two years ago, which prompted researching drogues. I encourage even coastal sailor to read-up on emergency steering with a drogue. We tend to think of it in terms of blue water sailing, but there are a lot more logs to hit near the coast!

The PS heavy weather testing was trimmed for space. Within that, a topic that I would like to see more people try is two drogues in series. I did considerable testing with Seabrake/Galerider combo, and a Delta Drogue/Galerider combo, though other combinations could work just as well. It seems to have many of the advantages of a JSD (higher drag, and the drogues are stabilized against pulling out of steep waves, the Achilles heel of all single drogues), with greater flexibility (single drogue can be used for steering and more moderate conditions) and easier recovery. The rode between the two will typically be 100-150 feet, so that they are not in the same wave. Very stable–I tested them up to 12 knots.

Dick Stevenson

Hi John,
Since the devil is certainly in the details, I have wondered what degree of strength deterioration occurs when a webbing loop is forced around a tight corner such as happens when a loop is lashed. The forces are across the width of the webbing and when this connection comes under load, would make for differential loading of the individual yarns (and may differentially load the stitching as well). The picture you include (with the tape measure) is under little load and clearly shows the outer edges taking the brunt of the little load shown: when load increases, the outer yarns look like they will take the full load while the middle portion just goes along for the ride. For a while and for this reason, I dead ended webbing (stitched loop) to a D shackle where the webbing loop went against the straight part of the D shackle rather than the curved. This did not last long as I disliked adding D shackles to the overall system.
My solution was to run small diameter high modulus line down the interior of my tubular webbing and to dead end it with 2 round turns and a long series of half hitches. This worked on a number of levels: no real worry about rolling underfoot as the line is in webbing and further, mine is a centerline system (center mast to the pointy end, quasi centerline mast to dodger), interior HM line is protected from UV, and no worry about stitching. There are still question marks and I will be reviewing things when I return to Alchemy in the light of your thoughts and suggestions.
Thanks for your thoughts, Dick Stevenson, s/v Alchemy

Dick Stevenson

Hi John,
Agree about the load sharing and your other points. It just makes me a little nervous to see things that I depend on scrunched together as happens when the radius is small. Something to keep an eye on and add more lashing as you suggest. Dick

Noel Grant

Great article and really important research I don’t see anywhere being done anywhere else and why you guys are the only subscription service I continue to pay for. We sure get our monies worth.

Eric Klem

Hi John,

This seems like a very good set of recommendations to me. Like you, we use polyester webbing although I suspect that the stuff you use is superior to what we have. We did try nylon at one point and found it to be too stretchy plus it would get longer when wet which wasn’t good. Your point about the stretch is very important. To visualize this, your range of 3-5% stretch at load means that the center will deflect sideways by 12-16% of the total length and the loads in the webbing are 165-210% of the loads in the tether assuming individually constrained jacklines.

The UV numbers you heard are a little alarming but shouldn’t be overly suprising. This makes me think that a good piece of line may well be the answer for many as you suggest assuming centerline jacklines. With the wide selection of line available, you can play with the diameter and material to get the correct stiffness and longevity. It would also be easy to deal with concerns over strength loss at terminations by simply going larger in diameter (increased stiffness and UV resistance) with a stretchier material and knots so that the de-rated strength is still well above the standard.

One interesting problem that I have run into on a few boats is that jacklines can get too long and not have a straight path anymore. This commonly means that they are bent by the side of the cabintop and if you pop them up on top, you end up with a much slacker jackline than you would like that doesn’t constrain the person as well as it should. Your centerline jacklines look nice in that they are in a straight line with no obstructions so you don’t have this problem.



Hi everybody,
I have been following the jackline-related posts with a lot of interest as I am working on the deck layout for my custom built sailing boat. She is a 40-foot Van de Stadt on steel we are about to launch after 7 years of hard work.
I would appreciate some thoughts about the cockpit fixed points/jacklines.

Kindest regards,

Clive Arnold

Hello Juan,
On our centre cockpit Rival 41 we have a cockpit jack line fixed on the inner face of each side seat. When clipped to one of these with a standard 1.8m tether we can just reach the side deck to transfer to our (new!) short tether cockpit to mast jack line. Other advantages are good freedom of movement, less tether tangle, less rattles for the off watch crew, and we can actually reach the chart table or galley without having to unclip.

Marc Dacey

I am finding this a very fruitful discussion. Thanks to all the commenters making note of the finer points.

Paul Clayton

Re the UV issue – we cover our sails, perhaps we can come up with an easy and quick way to cover jacklines as well. I’m thinking a long narrow strip of canvas that could be wrapped around the jackline and velcro fastened. First thing after the anchor is down, cover the sails and cover the jacklines. Shouldn’t take but a couple of minutes. It might add years to the life of jacklines, especially in tropical climates. Alternatively, unclip them, roll them up and bag them. With the soft shackle you use on the bow, unclip it and roll it back to the mast to a bag. The other jacklines could have a soft shackle on one end that would allow something similar.

Bill Koppe

Hi John,
Thanks for raising this important discussion.
Looking at the tight jackline we see that the load at each end is a multiple of the harness load depending on the angle the jackline makes away from the centreline.
So if that angle was 2 degrees the multiple is 14.32, 5 degrees 5.73 and 10 degrees 2.88.
Also if a 200 lb person fell 6 inches the the shock load is 4x or 800lb.
Then if the angle was 5 degrees, the total load becomes 4584 lbs, and if 10 degrees, 2304 lbs
If more than 1 person is clipped on, the loads increase in proportion.
Of course using your split jacklines 2 people could be accommodated with a jackline each.

Jim Kevern

Hi John,
Looking at the photo of the mast base, why not make the Cockpit to Mast a single jackline passed around the mast instead of relying on two stitched loops? Yes, it doubles the length, which doubles the stretch, but it seems they’re shorter to begin with. If that’s a concern maybe have it do a round turn or two around the mast.


Just wanted to say that that comment is one of the many reasons why I love this website and have no problem paying for the vast knowledge and research, it’s truly priceless. You have no problem with taking advice or doing something different that someone suggests. I find it refreshing when reading your posts and comments to your character but also, how truely amazing this community of wisdom and experience really is. Kudos, sir and keep doing you.

Just thought I would say something,


Charles L Starke

Hi John & Jim
Would you clarify this last suggestion? How is the jack line shorter? Do you mean one midline jack line from cockpit to bow, turned several times around the mast? Or a doubled jack line from cockpit to mast? Don’t any of these suggestions have at least two sewn loops? Maybe I can reuse my side deck jack lines individually at midline position by wrapping the slack around the mast.

Petter ;-)

Thanks for yet another good article, John. There are no brownie points awarded for guessing what has been added to the ToDo list when I return to the boat later this winter.

However, rather than stitching a loop at the end of the jacklines, how about tying a loop using an overhand knot or another more suitable knot? That would be both faster and easier. I would be curious to hear your – or other reader’s views – in this regards, when you find time.

New Years greetings!

Petter ;-)

A cat sailor has written quite a bit about jacklines and tethers. This is where I first came accross the idea of using a know on webbing rather than sewing it.


He has used knots on the end of the tethers. Maybe his ideas and thought may add something to your upcomming article on tethers.

This is the full list of post on the subject

// p 😉

Dick Stevenson

Hi Petter,
I have found webbing to be tricky stuff. Regular knots can hold, but, more importantly, may be very difficult to untie. The specialty knots for webbing are far better to use and can be gotten online. Webbing on cleats done in a conventional manner will hold and then slip unexpectedly so I use a series of tugman’s hitches. That said, all of the above has meant that my actual experience is limited. I suspect climbers have made onboard use of webbing more useful.
My best, Dick Stevenson, s/v Alchemy

Petter ;-)

So another day learning a new trick. Thanks for the Tugmans hitch, Dick.
As regards end, or connecting, knots on webbing, I think an overhand on the bight – or water knot – is deemed secure – at least in climbing circles.

Any views on this Dick?
// p 😉

Dick Stevenson

Hi Petter,
Generally, I would trust a climber’s judgment on knots with one caveat that is not based on climbing experience. I believe their knots are not left tied for long periods and subject to repeat tensioning and getting soaked with (salt) water. A knots being secure is important, but almost as important to me is the knot being easy (or fairly easy) to untie after use, repeated tensioning and periods of soaking/drying in salt water. What little experience I have with webbing is that the knots get pretty ornery after a while.
By the way, one of the attributes of the tugman’s hitch is that it is very secure, but always easy to let go.
My best, Dick Stevenson, s/v Alchemy

Petter ;-)

….. and, Dick. as you point out the overhand knot, most likely falls into the category of “severely difficult” to untie. But if used at the end to creat a permanent loop, untying is not an issue.
Let see what Johhn has in store for the next chapter on jacklines and tethers.

Jay Peters

Thanks for a GREAT series! My jacklines are going centerline this spring! For said jacklines (and tethers also, I suppose), could we not use Dynema or other modern high-strenght rope) spliced and covered with flat nylon tubular webbing for UV and roll resistance? Thanks, Jay

Helen and Brian

After reading Drew’s latest article in Practical Sailor (vol43(12)) it seems that a combination of Dyneema jack lines and DCR tether would be a sensible compromise. The DCR provides the elasticity required for both static attachment points and jack lines with limited stretch, providing of course the attachment points for either are suitably robust. The Dyneema would also withstand the UV degradation and can be easily spliced.

Kevin Gray

Has anyone tried to purchase a roll of Dacron from Pam Narrow Fabrics lately? I just tried to email their sales@ address, but the email got kicked back. If anyone has had luck elsewhere for similar strength webbing, I’d be interested in hearing about it. Thanks!

Bruce Bayne

I just purchased a roll of the webbing from Pam Narrow Fabrics. My original emails went unanswered, but I did get to someone via phone and a sales person responded via email. The person who responded was Leigh Harris (moc.scirbafworranmap@sirrahl) and he took care of me quite nicely. The price has gone up and is now 67 cents a foot. Hope this helps!

Drew Frye

Good article. I have done a few things differently, but it’s a different boat.

Cover the Stitching. Heavy whipping twine such as John uses degrades very slowly in the sun compared to lighter thread (I have measured sewn splices as loosing less than 5% per year–less than the webbing). But you can still cover the stitching with tape or fabric covers. I slide 2-inch tubular webbing over my sewn splices and lashings to keep the UV off. Just a few stitches hold it in place, and it’s easy to slide out of the way to re-lash or inspect.

Rope. I like it because with my layout, I can keep it off the deck (it runs along the cabin chine). It makes a better handhold, like a railing, and the UV life is very long (I use 1/2-inch).

Bolt Hangers. I like climbing bolt hangers for several reasons. I know that the testing is exhaustive. They are cheap even in 316 SS (hardly matters for safety gear, but I use them for other lashing points too). I can mount them with a single bolt (backing is still vital). They are compact. They are deigned for clipping biners.

It really is in the details. Just one weak link….

Drew Frye

You are correct about the loading direction. They work for me because:

a. Jackline anchors are only loaded parallel to the deck. The tiny amount of inboard-outboard deflection is compensated for by pivoting on the single bolt. The small vertical component will not cause bending. This is what they are designed for.
b. Hard top anchors. I have two on the aft edge of the hard top that protect the transom area. Very handy, because high anchor points restrict fall distance much more effectively than deck level anchors (I believe you have mentioned this). They also tangle less. Because the anchors are at chest level, there is no upward component. If I take a hard fall to the side, they swivel, as per design.
c. My climbing friends that sail with me, and family members, instinctively recognize bolt hangers as safe clipping points. While that is distinctive to my personal culture, bolt hangers signify their purpose to my group as plainly as RED signifies a stop sign.

I agree they are NOT the best choice for cockpit anchors that can take a hard purely vertical force. However, in practice, I think this has not actually proven to be a hazard. Bolt hangers are used to protect severely overhanging climbing routes, holding massive outward vertical loads. I have never heard of a failure due to fatigue, and many of these have endured a thousand hard falls. Do we really expect a tether anchor to take thousands of repeated roll-over-type falls? I think a few, at most. Additionally, a climbing fall exposes the anchor to about 1.6x the fall impact (the rope is doubled over a carabiner, like a pulley). Bolt hangers are a surprisingly tough, simple, and very well proven design. The lack of welds is important. Though not pretty, they have a proven functional elegance. No marine equivalent is as well proven for the purpose.

Finally–and important to this entire series of articles–crew must be trained that safety gear is NEVER EVER used for any other purpose. If they cannot absorb that, they get left on shore. Harsh, but basic. Climbers don’t tow cars with climbing ropes and carabiners. Thus, misapplication is basically unthinkable in on my boat. The conspicuous purpose of bolt hangers, for us, reinforces this.

Just an opinion that may not work for everyone.

John S

Researching a source for web material, I see that Pam’s site is “under-construction” so detail like cost and such are not readily available to a shopper on the West Coast. In looking for product with the specifications, as I understand, (Polyester “Dacron”, 6000 force lbs about 26 kNewtons) leads to no less than 1.75″ widths, and more like 2″. Is this correct? Additionally the weave would need to be “climbing” and not MilSpec so as to be able to stitch the end loop. Only product that comes close appears to be Mantra MK4 (a climbing webbing) and it has a breaking strength of 42.0 kN (9,450 lbf). A bit over the safe limits you described. $74.95 for 100 ft.
Am I understanding this material correctly?

Andrew Reddon

The post and comments are very compelling and helpful. Thank you. I am considering rope jacklines at least for centre-line on cabin top where there is little or no foot traffic. Double braided dacron – 5/8 – has lots of breaking strength (16,000 lbs) but elongation obviously depends on load. I am trying to figure out the load at which 3-5% elongation should be the target. Seems logical that it would be at the the breaking load but for rope, 3% is the elongation at breaking for Spectra lines. For double braided dacron, elongation at breaking is much higher. For some 5/8 double braided dacron, 5% is seen at around 15% of the maximum load – say around 2400 lbs rising to 9% at 6400 lbs. I wonder if anyone has comments or experience.

John Gaffey

Wow. Just, wow! So much good stuff!
(And, I have only a Kent Ranger 20 that I sail on our local lake spring–fall. Basically, my AAC membership is just guilty-pleasure, geeking-out by ease-dropping on what the big boys and girls have to say. That said, my boat is sitting out the winter next door on its trailer, so now would be the time for me to attempt a prevention system as is being discussed here–suitably scaled, off course. )
So, per using a rope centerline jackline system, what sort of terminal gear/knots will people be using to affix the rope centerline to the various strong points on the boat?
I’m also a member of PS, so if there is an applicable article there, a link or citation by way of answer would be great.

Cheers All,
John Gaffey

John Gaffey


Please disregard my above post asking about centerline, rope jacklines: I found all the answers that I need, and some, in the subsequent two articles on ‘Tethers’.

John Gaffey

Chuck B

John, thank you so much for all the incredible detail, information, and discussion on this important topic. I’m finally getting to designing and constructing my jackline and tether system, which has benefitted enormously from the experiences shared here. I’m wondering how you decided on your hand stitching pattern and number of stitches? I read the linked PS article on hand stitching, but based on the description and the photo, it seems that they’re recommending a pattern that looks different from yours. The stitches they tested that performed best appear to go “across the width,” 7 x 1/8 inch stitches for 1 inch webbing (perpendicular to the “long” axis of the webbing, if you will), and with a number of rows of this. Furthermore, they tested nylon webbing, and I’m hesitant to apply those findings to polyester webbing, since it was clear from the PS article that the stretchiness of nylon was a significant factor in dictating optimal stitching pattern.


Chuck B

Ah, how could I have forgotten your loft days? 🙂 Understood — thanks for your input.

David B. Zaharik

Love your closing comments…Phyllis is lucky … or maybe not… maybe you are ??

Alain Côté

Hi John,

I have to start by echoing other comments made: an amazingly valuable series of articles. My Boréal 47, “Snowstar”, bought used, came equipped with side-deck jacklines, which I am in the process of banishing forever! They are Wichard Lyf’safe jacklines and I have a question on attachment points. I have taken note of your comments and will try to get a roll of webbing from Pam’s to replace the Wichard webbing, but I am wondering about reusing the Wichard attachment mechanisms with the new webbing. You mention these devices as one of the reasons you looked at Wichard in the first place. Any thoughts?

Mark B

Has anyone found suitable webbing in the UK? The best I have found is 3000kg rated which only comes in white. Could climbing tape which is used to make slings work?

Mark B

Thanks John, I will try that.

Eric Klem

Hi Mark,

Try looking at companies that make transport materials. In many countries, the standard way to tie down loads on trucks is with webbing. These companies often have a good selection of webbing. You do need to know what your are looking for but you don’t get stuck with the 4500 lb rated stuff that you find if you look on amazon or someplace like that.


Daniel Coate

Hi, I’m trying to obtain the webbing you recommend. As of 10/19 is Pam Narrow Fabrics still in business? I’ve emailed and called and left messages a couple times without response? Any other sources for the webbing? I looked around and found that Strapworks.com has a “10K” webbing that is 2” wide, wasn’t sure if it was the same (https://www.strapworks.com/Polyester_Webbing_p/pew2%2810k%29.htm). Thanks so much!

Daniel Coate

Nix that question, i found it here…

Terence Thatcher

John, I knows I am late in asking but…. When you lash the jack line with small dyneema, what size do you use? And how do you terminate it? just a bunch of half hitches around the lashing, then sewn shut? Do you have an eye spliced into the dyneema to begin the lashing? If not, do you terminate with a square knot? Because the lashings take the load, can we discount the substantial loss in strength caused by the knot? Thanks.

Simon Gharibian

unfortunately the link from straps to go says it’s not stock and has a minimum order.
I found a far more economical source for straps rated at 6600lbs.
At only $50 for 300 ft, you could double it up…

Anthony Salotto

Hi John,

I’m a new subscriber, and have read your wonderful info on POB prevention. I’m installing a system on my new boat, and will be following your advice. One question: you’ve mentioned removing hard points, and going with jack lines. And you’ve mentioned having jack lines in your cockpit. But, I’ve not seen any details on this. How/where do you arrange the jack lines in your cockpit? Thanks!


Hi Thank you and all the contributors for the lifesaving investigative work on jacklines. Could you elaborate on the stitch or stitches that you use on the webbing. Is that a back stitch I see in the photo?

David Barker

Hi John
I’m ready to upgrade the layout of my jacklines.
You suggest a Harken 57mm round padeye with SWL of 1950kg as (almost) suitable – or similar.
Harken has a 98mm diamond padeye (#627) with SWL of 3540kg at less than 1/3rd of cost.
This should be ok if I install in correct alignment?

David Barker

Thanks for the reply John. To confirm that both padeyes are in Harken’s catalogue and I validated the cost difference from a couple of well regarded chandleries.

Eric Klem

Hi John,

Just guessing but if the price is actually tied to the cost to produce, then I expect it is due to the manufacturing method. The 316 diamond one appears to be cast whereas the 17-4 one is probably machined and welded. There will be some material cost difference but I doubt that is the driving force.

17-4 takes on many forms and they do tell you it is precipitation hardened (PH) but don’t give any more info so it is hard to tell what it actually is. The material properties are very dependent on the hardening, for example I spec a lot of H900 in my work. Pretty much any 17-4 is going to have a lot higher yield and ultimate strength than 316 so you can make smaller fittings by going to this material. It also has excellent fatigue properties although 316 is not bad. The downside is that for pretty much all corrosion modalities, 316 is superior or at least equal. A quick look to me suggests that the difference between these 2 fittings is that one is smaller and gets strength from a different material but is not as corrosion resistant so is suitable where highest performance is required and cost and corrosion are not as important.