Up 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.
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
Yes, sad indeed. I suspect that strain of competing with the large sailmaking conglomerates that get the actual work done in low cost jurisdictions got too much.
I gather from John that Lands End will be selling the Galerider, although not sure who will make it.
(I’m a big Galerider fan for emergency steering and stopping forereaching when heaved-to. That said, while interesting, I don’t think the recent PS testing tells us much about using a drogue in true survival conditions running off and for that we do recommend the JSD over the Galerider.)
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.
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
Just to clarify the webbing in the pick with the tape measure is under well over a ton of load. (#65 three speed winch.)
That said, it’s an interesting point, although I’m not sure that the it’s true to say that the outer strands are taking the whole load. That might be true with a very high modulus material like Spectra, but Dacron stretches and the weave of the webbing will set and distort, so my guess is that the load is pretty well spread.
I guess the only way to know for sure would be to destruction test, but given that we have a pretty huge safety margin I don’t think that really required.
Further with at least 10 turns of Spectra, as we advise above, I think the load will be even further spread. Those who are worried about this could take that up to 20 or even more turns to further spread the load on the webbing.
Nor would I use D rings, because one that would match the strength of the rest of the system is going to be pretty large and therefore probably won’t stay put in the correct orientation, and even if it did, I don’t like adding more hardware than I must.
As to using a mix of HM line and webbing, I’m not at keen on that for the reasons I list above.
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
I agree, more lashings indicated, I will change it. Your comment also brings up another important point: the reduction of strength from terminations, however they are done, is just another reason to build these systems with a good big safety factor.
I need to make that even more clear in a future revision, thanks.
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.
Thanks for the kind words. Makes it all worth while.
Based on the conversation between Dick and I above, I have, this morning, made a couple of changes to this chapter:
Added the following under safety margin:
And upped the number of recommended turns of Amsteel to 20 from 10.
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.
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.
Good question. I thought about getting into cockpit options in the post above, but was already up to 2700 words, so did not.
However, I will make sure that I cover that in the next chapter on tethers.
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.
I am finding this a very fruitful discussion. Thanks to all the commenters making note of the finer points.
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.
Good idea, I think that would work. I guess the trade off is the trouble to benefit ratio. I hand sew pretty quickly, so making up a new set from a roll of webbing every three seasons is probably less trouble, but that’s just me.
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.
Yes, I take a deep dive into this, including a graphing it, in this chapter: https://www.morganscloud.com/2015/11/18/person-overboard-flawed-jackline-systems-part-1-corrected/
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.
Yes, could definitely do that next time. This time I was experimenting with a lot of different set ups, and this is the one I ended up with.
Hi Again Jim,
I realized that I should have also said that your idea is a really good one, and one I had not thought of. I will definitely be doing it your way next time.
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,
Thank you for the kind comments. I try really hard to keep an open mind. That said I do have to watch myself carefully to make as sure as I can that I don’t slip into we this-is-the-way-I-have-always-done-it-itus. It’s a terribly easy mistake to make, particularly as I age.
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.
No, not from the bow. The lines we are referring to are the two jacklines that run from just forward of the cockpit to the mast. You can see then in this post: https://www.morganscloud.com/2015/12/05/person-overboard-better-jackline-systems/
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!
Thanks for the kind words.
I did try tying knots in the webbing, but found the result too bulky. It’s also hard to get a knot to set properly in the thick and stiff webbing we use.
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 😉
That’s Drew, who often comments here, and I’m an avid reader of his blogs, and yes, some of his ideas are featured in both this post (see “further reading”_) and in a future chapter on tethers that I have all written.
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
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 😉
Do keep in mind that the webbing that climbers use is generally nylon and much lighter and more stretchy than the very heavy Dacron webbing we are recommending.
Added to my above. I’m not rejecting knotting webbing completely, but before recommending it I would need to see extensive testing, including destruction testing, in the heavy webbing we are recommending. On the other hand, I know, from testing done by Hathaway (to destruction), and some limited testing on my own, that stitched loops work.
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
I agree on your caveat about being cautious about applying climbing knots directly to boats. More in an upcoming chapter.
….. 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.
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
Thanks for the kind words.
I explain why Dynema is very dangerous for jacklines here: https://www.morganscloud.com/2015/11/18/person-overboard-flawed-jackline-systems-part-1-corrected/
And that goes double for tethers. I have a tether post all written, look for it in the next month.
I would highly recommend reading (or rereading) the entire Online Book before spending any money: https://www.morganscloud.com/category/safety/book-person-overboard/
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.
Hi Helen and Brian,
I will need to read that. It just arrived in my mail box.
That said, do keep in mind that with all due respect to Drew, he has no offshore experience,so we need to factor that in.
For example some of his ideas about which way one could fall off a boat, while I’m sure right inshore on his cat, don’t apply, I think, on a boat offshore, particularly running before the trade winds.
Anyway, I will read it and revert.
Hi Helen and Brian,
As promised, I read Drew’s piece last night. Excellent stuff, most of which I agree with, although I’m a little more concerned than he is about the problem of climbing rope rolling underfoot.
However, I would still stay away from Dyneema as a jackline material for the reasons I detail in the post above.
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!
The best bet is probably to give them a call. When I chatted with them about this article I got the sense that they were rather old school and not really comfortable with email.
516-867-1200 Sales 800 # : 800-645-2266
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!
Thanks for that update, very useful.
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….
Thanks for the added ideas. Glad to hear that the stitching held up so well in your tests. Particularly good news because that means that the HR&R spec stitching will hold up well too, since it is very close to the same weight as our hand stitch thread. That said, your idea of covering it is, I think, a very good one.
On bolt hangers, they sound good, but I think it’s important that prospective users understand that they are designed to take loads in only one direction. For example, I think I’m right in saying that a load at say 90 degrees to the deck they are bolted to would result in bending the hanger, thereby fatiguing it, as well as placing a lever load on the single bolt and probable deform or damage the deck too. So if there is any chance at all of these kinds of loads a pad eye with two or four bolts would be a lot safer.
My point being that when an attachment point is available, sooner or later, probably in an emergency after a breakage, someone will attach something to it that the installer never envisioned and therefore I’m more comfortable with good quality pad eyes that can take loads in all directions, albeit with different fail loads depending on direction.
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.
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?
If you give them a call as I did, armed with the stock number (above) I’m sure you will be able to get a price and shipping.
As to other webbings, HR&R put a lot of research into this, including destruction testing, before settling on this webbing, so I really don’t want to get into trying to figure out other webbings. That said, if a webbing you find meets the same specification, without being wider, and is Dacron, I think it should do fine.
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.
I think the governing factor here is probably jackline length. Since your use is on the cabin top, I would assume that we are looking at a quite short span here? Given that, I think I would look at going down one size to 9/16″ to get a bit more stretch and shock absorption. That is assuming a breaking strength of about 10,000lbs. I’m also assuming here that since it is a centre line jackline, you won’t have any trouble conforming to the one foot rule.
As to elongation at various percentages of break load, I have not been able to find any good data on this, but given that quite small amounts of jackline elongation give a lot of shock amelioration, being exact here probably does not matter too much. I would also pre-load the rope hard and probably tighten it up a couple of times early in it’s life while the rope and splices are settling in.
Drew, any thoughts?
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.
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, 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.
I can’t say I have done any testing of the pattern I used. Rather it’s just the way we used to stich webbing back when I was sailmaking. That said, back then we used to hand stitch in clew rings that took very high loads with webbing, so I think it’s probably fine, but not having tested it to destruction, I can’t guarantee that. If in doubt I would go with PS since as a general rule stitching holds better in a less stretchy material (I think) and therefore if it tested well in Nylon, should work well in Dacron.
Ah, how could I have forgotten your loft days? 🙂 Understood — thanks for your input.
Love your closing comments…Phyllis is lucky … or maybe not… maybe you are ??
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?
Good question. Unfortunately although I did not try it, I’m pretty sure that the Pam webbing is too thick for the Wichard end fittings, so there’s nothing for it but to stitch to make loops.
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?
I think climbing webbing is made of nylon. If I’m right about that then it’s not a good choice for jacklines.
One other thought. Try checking with a sailmaker for heavy Dacron webbing. Back in the day when I was sailmaking we used a bunch of it.
Thanks John, I will try that.
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.
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!
Nix that question, i found it here…
Wow, that’s great. I will change the link in the post. Thanks so much for researching that.
I’m at the boat show so a bit busy, but leave it with me and I will see if I can find out. You definitely don’t want get 2″ webbing, way too wide.
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.
As I remember it’s 1/8″ but I don’t think the exact size matters much as long as we use enough turns. And yes I end as you suggest.
I start with an eStar knot, but again, with the plenty of turns, I don’t think this matters a lot. A lashing done this way is so much stronger than the the rest of the system that it’s just not stressed much. For example I have been using a lashing like this to terminate the runners at the mast on MC for years, and have never had a problem. The loads in that application are way higher than on any jackline.
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…
Thanks for searching that out. That said, I would want to handle it before using it for a critical application like jacklines. Often there is a good reason that stuff is cheeper! The other issue is thinner webbing will degrade exponentially more quickly in sunlight.
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!
Good point. I cover that here: https://www.morganscloud.com/2021/01/22/cockpits-part-2-visibility-and-ergonomics/
I will add a link to that, to this chapter. Thanks for the heads up.
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?
I’m not sure what to add to what the photo in the post and what I have already said. Also, I’m not sure what a “back stitch” is, since we never used the term when I was sailmaking. Anyway, both the edge stitching and the middle line are stitched in two passes, one each way through the same holes.
Hope that helps, but if you have a specific question, I will try to answer it.
That said, if you really want to geek-out on stitching check out the article at Practical Sailor I link to above. The cool thing about that piece is that it includes destruction testing.
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?
Strange that there would be such a large price differential. I guess I would dig into that and see what the differences are before making a final call. I would also make as sure as I can that the cheaper pad eye is not a counterfeit. I have not researched this, but it seems like a heck of a price difference.
Anyway, all other things being equal, changing to the diamond does not seem like a problem, although that is based on only a couple of minutes thought and is not a solid recommendation.
Hi Again David,
I just noticed that the round pad eye is 17-4 SS and the diamond 316 which might account for the price difference, but I really don’t know enough about quality differences to opine on which to use. Anyone else?
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.
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.
Thanks so much for that. Given my limited knowledge of the differences I was not comfortable just guessing that the cheaper alternative would be OK. Your analysis certainly makes sense to me.
Hi, John. The link to Straps to Go doesn’t go directly to the product any more. Looking at their site, I assume that this is the product you were linking to but can you confirm please: https://strapstogo.com/webbing/polyesterwebbing.php (although I don’t see yellow)?
The material is right at that link, but I could not find any with the required strength on the page. Seems like the max was a little under 4000 lbs, so not strong enough, and that’s before any UV deterioration.
See the article above for our recommended strength. It may take a bit of research, and maybe some calls to find something, but I would stick with the above requirements. Probably best to start with a call to Straps to Go to see what they may have.
Here’s another possible source:https://jimmygreen.com/webbing-jackstays/78693-29115-50-metre-roll-jackstay-polyester-webbing-25mm#/212-colour-blue
Not quite as strong as the stuff we were using but way over ISAF requirements. I have also bought stuff from Jimmy Green and they are good folks.
Thank you, John. That link to Jimmy Green is very useful even just to help my local sail shop in Belgium understand what I am looking for (getting stuff from the UK is fraught with extra expense these days). I was looking at Straps to Go as I am more often in the US and can take stuff back with me. Anyway, I am sure I will get there. Thanks again (P.S I am definitely sticking to your recommendations).
When I was looking, I found it much easier to search by the material, width and breaking strength as it seems there are standard values for breaking strength. Otherwise, I was finding all sorts of 1″ stuff with breaking strengths in the 1-4000lb range and it was overwhelming the amount of stuff to look through. I ended up getting my webbing through Lodi Metals who has all sorts of cargo gear. They were able to give me a material cert and strength cert so I had confidence I was getting something decent. Once I knew how to search, I quickly had a handful of promising options.
Thank you, Eric that is very helpful. Nice to see a company that actually provides some specs. The webbing I found at Lodi that looks right is this one (is that what you got?). But for the time being, because I am running out of time and I am not convinced of my own ability to actually do the sewing correctly yet, I have decided to get the pre-made jacklines from West Marine. They have a 6000 pound breaking strength and get a good review from Practical Sailor. I will buy a shorter piece of webbing to practice sewing this year, and when the time comes to renew, I will make my own (which will be a damn sight cheaper).
That may very well be what we used, the strength looks right. I used a lower breaking strength number than John because we have very consciously set our boat up for coastal cruising.
Out of curiosity, I did a google search for “9800lb 1″ polyester webbing” and get several hits of webbing of that strength such as https://www.bairstow.com/1-Yellow-9800-Square-Inch-7-Polyester-Web-6000-p/901-1p.htm and http://www.americanwebbing.com/polySling.html. I haven’t actually looked into these products at all to ensure they are suitable but given that there were several hits in the first few results, it seems promising to get to John’s numbers with a quality product.
Thanks for researching that. This seems to be a continually moving target, but as you point out, a bit of searching always seems to come up with a new alternative.
Thanks again, Eric. Indeed finding materials in the US is relatively simple compared to finding materials in Europe (not including the UK). Waiting till I visit the US is not always an option. Anyway, thank you for the searching and I have some sources for the future.