Yes. The internal line with a weight is a good idea. Probably needs a
extension arm at the top to hold the weight away from the tower so the
weight clears the rings. That rigging and bracket need to be strong
enough to withstand a fall - 250# x 10g = 2500# plus a 2x safety factor
as OSHA lanyards are rated 5000# break. Another way to rig the safety
line is to exit the internal line at the top guy and run it beside that
guy with just enough tension to keep it out of the antenna elements (7
rings on my tower). Then the challenge remains of threading the safety
line through the elements to use it. It seems to me most falls on OSHA
lanyards will have other injuries from contact with stuff. A max fall
from above the tie off is the lanyard 6' static plus 6' dynamic or 12'.
My tower climbers are also technical climbers, so climbing over the
rings is within their skills. I'm pretty sure I couldn't do it (+40
years age difference). The rings also limit who will take a climbing
job on my tower. A good reason to use swing arms instead of rings for
independently rotating side mount antennas.
Grant KZ1W
On 6/16/2016 5:29 AM, ve4xt@mymts.net wrote:
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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