I use a Petzl Navaho Complete full body harness, an earlier model of the
current Navahoe Bod:
http://www.petzl.com/us/pro/verticality/harnesses/work-positioning-and-fall-
arrest-harnesses-0/navaho-bod
The harness has rings on the front and back, but I use only the back ring
for the fall-arrest lanyard, mainly because that's what's been recommended
here and it seems at least as safe, or safer, than attaching the lanyard to
the chest ring.
That said, I question whether it's really true that there's a greater risk
of injury with the chest ring. Remember that the ring is placed relatively
high on the harness, not at belly level. It seems to me that the attachment
point is so far above the center of the back that it can't bend the spine
backwards. Put another way, the center of gravity is way below the
attachment point, so I don't see how the legs could swing upwards and you
could end up horizontal with the lanyard pulling the center of your body
upwards. The mass of the body below the pivot point is much, much greater
than the mass of the body above the pivot point.
I suppose there might be a scenario where you fall backwards head first and
your chest gets pulled up by the lanyard and your legs continue to swing
around and bend your spine backwards. But I would think the whole body would
pivot. I'd like to hear some comments on this.
Seems to me a similar face-forward fall with the lanyard attached to the
dorsal ring could break your ribs.
I don't think it's all that different whether you end up suspended from your
chest or from your back. It's going to be bad either way, and imperative to
get out of either position ASAP.
Note that the the dorsal ring is mounted high as well, so I don't think you
would double over if pulled up by that attachment point, either. I believe
these back rings are sometimes used to attach a restraining lanyard when
someone has to lean out from the tower or rock face. Newer harnesses like
the Navaho Bod have an attachment point on the back of the belt for that.
My harness does have a waist ring, and that surely would be a bad place to
attach the fall arrest lanyard. I'd either end up breaking my back or
flipping upside down, or both.
Another data point is that much of the Petzl literature, for both harnesses
and lanyards, show the fall arrest lanyard attached to the chest ring, not
the doral ring. This is true even in drawings showing use on a steel
structure like a tower. I've seen photos of rock climbers and rescuers with
chest lanyards, too.
There's a reason I'd rather use the chest ring: the body doesn't get in the
way of the straps when climbing. If I attach the lanyard to the dorsal ring,
then the straps must pass over my shoulder, not under one of my arms (if you
fall that way, you'll probably break an arm or dislocate your shoulder.)
When attaching one of the hooks, I often have to move the strap around my
arm (or vice versa) to make sure the lanyard doesn't pass under my arm. This
takes extra concentration, awareness and motion. If the lanyard was attached
to the chest ring, then this would not be a problem and the climbing motion
would be much more efficient and natural. Believe me, any wasted energy can
be very costly when climbing a tower. Another benefit would be not needing
as much strap length to reach higher rungs (though my body length is a
bigger limiting factor.)
I suppose one possible disadvantage of the chest ring is that the lanyard
might get in the way (or in my face) more when at the work position. I think
that would still be preferable to the hassle of managing the lanyard passing
over my shoulder.
All that said, until someone with real expertise tells me otherwise, I'll
continue to attach the lanyard to the dorsal ring.
Another subject: the lanyard. For a number of years I used the Petzl
Absorbica Y MGO Y-lanyard:
http://www.karstsports.com/petl59mgoaby.html
(It was a lot cheaper when I got mine.) It has large gorilla hooks, but it's
relatively heavy because of the hooks, the hooks take a fair amount of hand
pressure to open (leading to hand fatigue, especially on the way down), the
lanyards tend to get tangled with each other, and the sock tends to slip
down and expose the shock absorber (the current model has a zippered cover,
which is much better.)
A couple of years ago, I saw this at the Outoor Retailer Show in Salt Lake
City:
http://www.blackdiamondequipment.com/en-us/shop/climb/via-ferrata/easy-rider
-via-ferrata-set
I was immediately attracted because the lanyard is super light and the hooks
are much easier to operate. The lanyards have elastic inside that
automatically retracts them to the minimum length needed. When extended,
they're a little shorter than the Absorbica Y MGO, but still plenty long
enough to easily extend as far as I can reach above my head. The cover is
zippered, too.
This lanyard is designed for a climbing technique called Via Ferrata, where
a steel cable is strung up the face, secured to the face every few feet. You
can clip onto the cable, but must unclip at each point where the cable is
secured to the face. Hence, the need for a Y-lanyard to stay 100% clipped
in. A similar technique is required for safely climbing a tower. In fact,
though Petzl markets the Absorbica Y MGO for an industrial and rescue use,
it's sometimes called a Via Ferrata lanyard. I suspect the large gorilla
hooks make that use difficult, though.
I was somewhat concerned that the smaller hooks would be more difficult to
quickly snap to a tower rung. You can hold the big gorilla hook by the
bottom and slap it onto the rung, and it looked like the small hooks
wouldn't allow that. Turned out to be no problem. The strike area is a
little smaller, and you can't pivot the hook in the same way, but it slaps
on just fine once you get the hang of it (no pun intended.)
As I was preparing this post and looking for a link to the Absorbica Y MGO,
I came across this:
http://www.petzl.com/us/security-alert/2011/05/19/request-immediate-self-ins
pection-all-absorbica-energy-absorbers
Glad I switched!
Of course, for legal reasons I'm going to disclaim any liability for my
favorable post on these items. Use at your own risk.
73, Dick WC1M
-----Original Message-----
From: David Gilbert [mailto:xdavid@cis-broadband.com]
Sent: Wednesday, September 28, 2011 2:50 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Harness, Gorilla Hooks
"What am I missing here??"
LOTS.
An eye in the back between the shoulders is exactly where you want it to
be to restrain you in a fall. An eye in back will most likely spin you
around ... face away from the tower ... but more importantly it will not
snap your spine at the neck like it would if it was in front of you.
Think about which way you want to be bent with a sharp jerking motion.
Using hooks with no latching gate mechanism to climb a tower is just one
step below suicide and there is a very good reason you didn't see them
at any dealers. In my opinion, anyone who uses anything like that to
climb a tower better have a lot of life insurance and a family that
doesn't much care about them. The latching gate on a proper climbing
hook is trivial to engage/disengage, and if you can't manage that you
will probably have difficulty with anything else you do on or around a
tower as well. I spend considerably more time making sure I am clear of
the straps attached to my gorilla hooks as I climb (they blow in the
wind) than I do actually engaging or disengaging the hooks themselves.
Dave AB7E
On 9/27/2011 8:57 PM, Wilson Lamb wrote:
> I just bought a Klein harness, which has an eye in the back, behind the
> shoulders. This looks like a very bad idea to me, since a fall will
surely
> drive ones face into the tower. With a little bad luck, it will hook ones
> chin on a brach and break ones neck.
> What am I missing here??
>
> Steve's harness has no chest hook, so if using a runner one will wind up
> hanging more or less horizontal, with severe stress on the spine when
> fetching up on the lanyard.
> What am I missing here?
>
> Re hooks: I saw some guys climbing a while back with large OPEN hooks,
> which were great for easy moving while climbing. They were like giant
fish
> hooks, maybe four inches across the opening...no snap gates to deal with.
> What are they called? I didn't see them at any of the dealers.
>
> Obviously I haven't started climbiing yet, but hope to soon.
>
> 73,
> Wilson
> W4BOH
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