The Offshore Voyaging Reference Site

Flawed Jackline Systems, Part 2

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In the last chapter we learned that being drowned by dragging on our tethers or badly hurt by fall-arrest shock loads (most likely a combination of both), is probably at least as big a threat as going overboard untethered and not being picked up.

In this chapter I’m going to apply a bit of simple arithmetic rigour, backed up by testing, to common jackline systems, and particularly the ones we have used on Morgan’s Cloud, and see if said systems will keep us out of the water—something I should have done years ago.


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Dick Stevenson

Hi John,
Nice analysis.
I have done the “hanging from the harness” exercise that you showed pictured and decided that if I went overboard, I would attempt to keep my arms down by my sides. Even my easily adjustable Lirakis harness is too loose when worn at a comfortable pressure and those I have observed in inflatable life vests that also serve as a harness were absurdly loose and very likely to be pulled over one’s head in a powerful snatch. or do serious bodily harm. I have been looking for a harness where there are 2 leg attachments going around the leg ( different from crotch straps) as well as a conventional chest arrangement. I am still looking, but variations from other professions/recreations come close.
Dick Stevenson, s/v Alchemy
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Stein Varjord

Good post and an important one. My roots are firmly in racing, so I’ve been on boats where these topics were tested too, with similar judgements, but with no real good solution. The best we got to was that we made rules about moving on deck. They were about like this:
– Jackline can only by used on the windward side.
– Tether must be adjusted so it is about 1 foot too short to reach the lifeline, anywhere.
– Such attachment is ONLY for moving. At arrival, use fixed points and readjust tether length to same limits.
– Deck hands wear proper climbers harnesses strongly connected to a chest harness. When hanging fully on it, the tether attachment should be not much above belly button. This harness was also used when climbing the rig.

This worked, but I was never really happy with it and it was too slow sometimes, meaning one would frequently skip some steps and “just be careful”. Not good.

Stein Varjord

Hi John.

Exactly your point is why I was never happy with the solutions and rules. No matter how strong the rules were made, people would make potentially dangerous simplifications. I would even do it myself. Thus, the system might be much better than the average cruiser system, but the verdict must still be “Fail!”

Attaching to fixed points have the problems you describe, but if the tether is kept very short, so it’s already tight and even used to get support while working, shock loads should mostly be avoided, but then again comes the fact that we’ll use points that are not ideally placed, and adjust the tether way too long to reach something just a short moment, etc….. It will end up in too many risky situations.

Life jackets are slightly off topic, but I feel they still belong in the section describing the dangers of moving on deck and it’s definitely relevant in discussing why a good harness system is vital.

Countless times I’ve seen competent sailors step out of the cockpit intending to perform a task on deck. No harness and no life jacket. Then notice the task looks dangerous and immediately return to the cockpit. Then put on a life jacket but no harness and proceed doing what they just decided was dangerous.

In bad weather in the night, or even in daytime, the chance of finding a person over board is very close to zero, as probably all here will know. Even if found, getting onboard is very dangerous. If the vest gives you a feeling of safety, you are totally wrong. If that feeling makes you change your behaviour, the vest is directly responsible for increasing your risk of dying. Vests can give important additional safety in many situations, but in offshore sailing, life vests must kill much more people than they save.

Of course, a life jacket has no intention of its own. The real reason for its flawed effects is our own stupid emotions, but no matter how smart we are able to be, we’ll never stop being human. We’ll never stop acting according to our emotions at least as much as our knowledge and logic.

Our safety systems, whatever they are, must fit that reality.

I don’t know which good ideas will be revealed in the next chapters and discussions, but I’m very curious, since I’m certain that I’ll be wiser and safer after reading them. Coming from a wise ass like me, 🙂 that’s a pretty strong vote of respect and confidence in this site!

Jeff Bander

The working principle here is to stay onboard at all costs. Nothing good comes from reaching the water so that possibility has to be eliminated. In addition to the key practices of staying low, holding on (gloves help) and wearing grippy shoes, I think a little mental preparation can help. 1. Even if you decide to wear a PFD act as if you’re not; the darn thing can give you a sense of security that’s wildly inaccurate. 2. Even if you’re tethered when moving forward act as if you’re not; again the belief of protection may exceed the actuality 3. See the lifelines as protecting you not from the water but from the edge of a 100 foot cliff with sharp rocks at the base. Thinking this way may help avoid ever having to put the whole “safety” system to the test.

Keep those posts comings….we’re making progress.

Henrik Johnsen

An adjustable lanyard like the Petzl Grillon, which we use in our rescue service, will make it possible to always have the right (read: short enough) length on the lanyard.
http://www.petzl.com/en/Professional/Lanyards-and-energy-absorbers/GRILLON?l=INT#.VlbtuZN_NBc

PaddyB

“That’s an interesting alternative, but would we really adjust the length of our tether continuously as we moved around? I fear not.”

I’m also a huge fan of GriGri’s (grillion) onboard, but very hesitant to recommend them as a good idea for everyone. After decades working in the air adjusting the length is instinctive and automatic, not something which even gets thought about. For others with no experience it may well be a very different ball game and more intrusive than helpful. Personally single handing I never use a PFD but a lightweight climbing harness which might never be taken off for days on end offshore, combined with a GriGri it works well, lanyard is always as short as practical. Great at the mast as well, clip off and lean back so both hands are free.

Henrik Johnsen

I don´t think it´s possible to make a system that covers all aspects, and that one just can put on and be safe and sound. My experience from over 30 years in the rescue service has taught me that you constantly need to adjust your gear, and always take into consideration whatever the environment throw at you.
On board we put on at climbing harness in addition to the life vest, and attach the lifeline to the harness when the weather gets rough. That way we take the load of the life vest, should we fall in. This way we don´t have to think about the crotch straps breaking, and we´re lowering the attachment point of the lifeline with a good 50 cm, compared to when it´s connected to the life vest, which is of great importunes.
When the weather is on the mild side though, we trust the lifeline attached to the life vest.
Yes, this means we have to adjust the gear quite often, but that´s the way it has to be, and are of no concern to us. We do the same again and again without thinking about it when climbing in the mountain or moving around on glaciers.

Charly

My professional background is in climbing/rescue/work at height. So I recognize the potential value of a device like the Petzl Grillon in this application. I should point out that although the Grillon does have some load limiting capabilities, it is not intended to be used a shock absorber so without proper testing, I would caution against its use as such. I do believe however, these technologies (load limiting camming devices and tear away shock absorbers) could be applied to this problem with good results. Very much worth looking at for sure.

Dick Stevenson

Hi John and all,
Crotch straps as seen in the recreational marine environment are designed so lightly that they will likely only suffice to hold an inflated vest down so it does not ride up. Any kind of “harness” contribution seems illusory at best.
I went back to some past researches and found:
Harnesses w/ flotation and leg attachments such as I was referring to in my last email.
And shock absorbing harness tethers.
There are likely reasons these products are not readily applicable to the recreational marine area, but they reflect much more the way my thinking is going, especially the harness/flotation rig with its substantial leg attachments. I also suspect these products are well vetted by their professional users.
My best, Dick Stevenson, s/v Alchemy