Safety Tether

[Brion Toss]

As the above responses indicate, there are a lot of options for lifeline tethers, so many that I believe we have bumped the original question: webbing vs. 3-strand. As I understand it, webbing is the dominant material for this application because it folds flat so easily, and doesn't stiffen or hockle. Rope is handy, by contrast, when you have to run over a sheave. Different tools for different jobs. If I were going to use rope for a tether, I'd use the most flexy type --- single-braid --- and Brummel it at the ring ( a Ring Hitch is too bulky, too snag-prone). And I'd make it 2-legged, to lengths I prefer; I don't want someone messing with my gear.
As for length, the shorter the better. I have read too many reports of people drowning at the end of long tethers, which just happened to be long enough for them to fall over the lifelines and into the water. High enough lifelines and somewhat shorter tethers will help, and Ian seems to have something like that, but even with falling overboard prevented, I want the shortest possible potential fetch-up at any moment, which for me means chest-high jacklines. It also happens to mean material preferably stronger than 6,000lbs, which is a scant minimum in a shock load, particularly with wear factored in.
As for the awkwardness of clipping and unclipping, I certainly understand the attraction of a free run fore-and-aft; I just see the midship interruption as an entirely acceptable bother at worst, so of like seatbelts, and a distinct feature in fact, as it limits how far you can wash along the deck. And chest-high jacklines make great lifelines on their own, highest just where you are most vulnerable to going over: in the middle of the boat. I sometimes rig and use them even if I am not wearing a harness.
Fair leads,
Brion Toss

[Bob Pingel]

Brion-

Can you share some details on the implementation of your chest high jackline setup?

I am assuming chest high amidship, coming down to deck in a traditional manner fore and aft? Some attached the shrouds?

What is your prefered material for this setup?

Thanks,

Bob Pingel

[Dan Lehman]

Originally Posted by Brion Toss

As the above responses indicate, there are a lot of options for lifeline tethers, so many that I believe we have bumped the original question: webbing vs. 3-strand. ...
As for length, the shorter the better.
It also happens to mean material preferably stronger than 6,000lbs, which is a scant minimum in a shock load,

I'm surprised I didn't way back remark at the focus on strength, which I think is quite
misguided: the BODY cannot take much more than a ton, so strength beyond that is
all academic.
As for shock loads, that is a factor depending upon the material choice: taking typically
static webbing ensures higher shock, less energy absorption; taking typically elastic
(hard- not soft-) laid rope will lessen impact forces. There is some evidence in lanyards
used in caving, e.g., of the energy absorption of a Strangle Noose hitch (as compared
with a splice); but if a knot's bulk is an issue, well, just rely on material stretch.
Another aspect could be vulnerability to cutting? --rope is usually better, here.

.:. Seems like a decent, 7/16", half-inch firmly laid nylon rope should work fine,
spliced or seized or tied.

--dl*
====

[Brion Toss]

Hi Dan,
Yeah, I know that after a ton or so we'd be shedding body parts in a shock load; I just want a safety factor that signifies relative to a survivable shock load. Energy absorption is of course an issue, and there are a variety of ways to get that, but again, short tethers limit acceleration wonderfully. Likewise again, rope works fine, but bulk and stiffness can be an issue. As for cutting vulnerability, I rather like the idea of being able to cut a tether away quickly, at least in circumstances where accidental cutting isn't likely.
Fair leads,
Brion

[Ian McColgin]

Sometimes I think we're talking about different things.

I like jacklines inside all rigging so I can move to any part of the boat without having to unhook. I've happened to use three strand line but there's a good argument for purpose made tube tape jacklines that won't roll out from under foot.

I've used three strand, braid, and tube tape for the tether that connects the harness to the jackline or whatever. Frankly makes little difference to me.

I much prefer the basic figure 8 pattern harness with the cross at the back.and the tether through a D ring (if flat tape sewn harness) or 'biner (if rope) one one side, through a D ring or biner on the other, and back out the first ring. Size it so the closed up position is tight but not breath constricting. It needs to be tight enough that any harness parts, 'biners and whatnot don't clock you good under the jaw.

Such a harness can be worn loose until you fall and it will then close up nicely. Because it turns you around as you reach the end of your tether, the stress is spread across your upper back - the best muscled and protected part of your torso. Webbing is less uncomfortable in a fall, less bruising, but either will stop you.

Given how easy it is to make up a figure 8 harness, there's no reason for any crew to whine if they need harnesses and none are provided. Make it, like we all did in the 50's and 60's before modern rock climbing and the outdoor consumer products revolution from which we've all benefited.

G'luck