When raising and lowering the weight you'd have problems with it hitting a
ring and not being able to get past it, or getting caught inside a ring
between the inside edge and the tower face.
The pulley at the top would have to be rated for a man-load, too.
I'm not wild about the belay system because it relies on the belay man. For
jobs requiring hours on the tower, the belay man is going to get bored and
may lose concentration. If he screws up, you could die.
Yes, ring-mounted rotors are a problem, but it's possible to deal with them.
I think the best safety climb system for rings would be one of the rail
systems designed for climbing ladders. They're relatively low profile, so
when mounted on the tower face they wouldn't stick out far enough to hit the
inside of each ring. The rails come in 10' sections, so it's easy to
customize a system and install it yourself. A galvanized rail kit for my
tower would cost about $1,300, not counting the ascender.
Unfortunately, it looks like the rail systems require a minimum rung
diameter of 3/4". The cross-brace diameter on my Rohn 55 is less than 1/2".
My guess is that the rail manufacturers don't want you to attach them towers
because the cross braces, aren't as resistant to bending (or welds breaking)
as ladder rungs. There are clamps that attach to the ladder sides instead,
but they don't look like they'd fit tower legs. Maybe another manufacturer
has a leg-clamp that would work. If anyone knows of a rail system compatible
with Rohn 55, let me know.
A cable system can be used with rings by doing the same thing -- running it
through the rings between the face and inner edge of each ring. But it
depends on how far the top and bottom cable mounts stick out from the tower
face -- it can't be greater than the distance from the tower face to the
inside of the ring. I can't recall right now how much distance that is, but
it's only a few inches -- maybe 6 inches? It looks like the TufTug system
sticks out more than that, but I can't tell from the photos and they don't
provide specs online. This is not an item I would homebrew, so it would
require finding a commercial product with standoffs that don't stick out too
far. If someone knows of such a product, let me know.
Even if suitable cable mounts can be found, it seems likely that when
stressed with the outward pull of a climber, a 100' cable would hit the
inside of the next ring up, risking abrasion over the long run. Probably the
best cable solution for my tower would be to run three separate 30-foot
cables, one from the bottom to the first ring, and one each between the
bottom/middle rings and the middle/top rings. It would be nice to have
another 10-foot cable between the top ring and the top of the tower, but
that's gravy. I haven't done any research into other products, but the top
mount of the TufTug system looks large (maybe taking up a good bit of the 30
feet) and probably too expensive for this approach. Their fixed-length
systems are too long (80') and I don't know if they would make a custom
system, If so, my guess is that it would be expensive.
As you probably guessed, with all these solutions you have to unclip below
the ring and clip on above the ring. This will require climbing with a
Y-lanyard, but it would only be needed when climbing over rings or working
on the tower away from the safety cable or rail (which implies that you need
a Y-lanyard even with a safety climb system on a tower without rings.)
Nonetheless, given that without a safety climb rail or cable I have to clip
and unclip every two or three cross-braces, any one of the systems would be
a major relief in terms of fatigue and hand muscle cramping.
If anyone knows of a rail or cable system that would work, let me know!
73, Dick WC1M
-----Original Message-----
From: ve4xt@mymts.net [mailto:ve4xt@mymts.net]
Sent: Thursday, June 16, 2016 8:30 AM
To: Dick Green WC1M <wc1m73@gmail.com>
Cc: N3AE <n3ae@comcast.net>; <towertalk@contesting.com>
<towertalk@contesting.com>
Subject: Re: [TowerTalk] Sad news N5IA SK in tower fall (Shawn Donley -
N3AE)
Hi Dick,
It would get in the way of the rotation, wouldn't it?
What if you ran the belayer's line through the middle of the tower, through
pulleys at the top so in use, the line from top to climber is outside, but
when not in use, you'd use it to haul a weight to the top? This way, when
not in use, the climber's line is out of the way of the antennas rotating on
the rings. When you needed to climb, you'd undo the line holding the weight,
let gravity bring the line to ground level, attach the climber and up you
go.
Thinking you'd also need a snatch block at the bottom of the tower so the
line through the tower would come out horizontal to the belayer.
Ring-mounted rotators also defeat most other continuous-attachment systems,
don't they?
73, kelly, ve4xt
Sent from my iPad
> On Jun 15, 2016, at 8:25 PM, Dick Green WC1M <wc1m73@gmail.com> wrote:
>
> Interesting idea, but it wouldn't work with towers that have TIC rings.
>
> 73, Dick WC1M
>
> -----Original Message-----
> From: N3AE [mailto:n3ae@comcast.net]
> Sent: Wednesday, June 15, 2016 9:11 AM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Sad news N5IA SK in tower fall (Shawn Donley -
N3AE)
>
> It's with some trepidation that I respond to this thread, but there''s one
other climbing technique I have not seen mentioned in this forum.
>
> For modest height towers, say up to 75 feet, why not climb it like a
top-roped rock climb? Have two (redundancy) mountaineering grade locking
carabiners secured at the top of the tower with a suitable temporary rope
loop (like 3/16 Dacron) going to the ground through the carabiners. On the
day of the climb, use the temporary rope to pull some 9 to10mm static line
(like BlueWater Assaultline) through the carabiner to the ground.
>
> Attach your harness to the climbing rope and have a competent and properly
equipped belayer on the ground to take up the rope and protect you during
the climb. "Competent" in this context means someone you trust your life to
and vice versa...i.e. a fellow climber.
>
> Advantages:
>
> 1. Always on slight rope tension (provided by the belayer) so minimal fall
distance and shock loads.
> 2. No energy expenditure (or fatigue related mistakes) hooking and
unhooking safety lanyards to the tower during the climb.
> 3. Can concentrate on the climb with less distraction.
>
> Disadvantages:
>
> 1. Need to climb in a conventional safe manner once to get the carabiners
installed.
> 2. Carabiners will need replaced periodically 3. Need a competent and
experienced belayer
>
> Some comments on rope:
>
> A typical "dynamic" climbing rope with zero slack (belayer has slight
tension) will elongate by about 10% with a 180 lb climber on it. Example: 60
ft tower. Say you are only10 ft up the tower. So ~ 110 ft of rope between
you and the belayer. If you fall, the rope will stretch about 10 ft (but
like a bungee) and you WOULD land on the ground but softly. Fall near the
top: ~ 60 ft of rope between you and the belayer. So you'd bungee down about
6 ft. In either case, there could be risk of injury if an arm or a leg was
across a tower brace prior to or during the fall.
>
> A "static line" typically used for mountain rescue or rappelling into
caves, has an elongation < 3% (for a 300 lb load), so in the above example,
the "fall distance) would be < 3 ft and <1.5 ft.
>
> A "dynamic" climbing rope will be better at reducing shock loads in a
fall, but I'd be concerned about possible arm or leg injury if either got
across a tower brace member prior to or during the fall. That's why I'm
thinking a "static" type rope and zero slack at all times (belayer
responsibility).
>
> I've climbed towers and rock for many years. Not so much rock now that I'm
older. Always felt safer on a top-roped rock climb, even compared to
climbing towers with conventional "always attached" technique and gear.
>
> So how DO I climb towers? I use conventional methods and gear following
the "always attached" philosophy only because I rarely have an experienced
rock climber around to belay. Nevertheless, having been on both towers and
rock, I wonder which technique would be better (safety and efficiency)?
>
> OK. Ready for the incoming stones and rocks.
>
> N3AE
>
>
>
>
>
>
> _______________________________________________
>
>
>
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