Greetings gang;
I performed some gutter work on my 2-story home that required a safety
rope system. I was installing gutter guards in places I could not reach with
my ladder. I do not have a very steep roof, so footing was not a problem.
For work on the front of my home, I tied a dynamic climbing rope (a type
that has give to absorb shock loads) to a tree in my back yard and threw the
rope over the peak of the house toward the front. I used my tower climbing
harness (a Petzl model Navaho-Vario, an industrial combination seat harness
with side rings and a center suspension ring), and two lanyards made from a
loop of rope with a three-turn prussick knot tied on the safety rope, and a
locking carabiner attaching the lanyard to my harness. The knots will slide
easily on the safety rope with hand pressure, for adjustment, but will hold
tight when released. I used two lanyards of slightly different lengths, as
is commonly done in climbing, to have a backup while one is being adjusted.
I think they are better than ascenders for this application, since they can
change direction without having to be disconnected from the safety rope and
flipped around.
As I a worked my way toward the gutter, I connected one lanyard to one of
my side rings and one to the center ring. I alternately slid each of the two
lanyards out, a few inches at a time, keeping some tension on the safety
rope. Once I was in position, I worked with the safety lanyard pulled tight
on one of my side rings, allowing my arm on the opposite side to safely
reach out and over the gutter. This is fall prevention, not fall arrest,
since the safety rope is already pulled tight, supporting a large portion of
my bodyweight. In fact, due to the elasticity of the rope, I set the lanyard
a bit short on purpose so that some effort was required to stretch the
safety rope to put me in position. Relaxing a bit resulted in my being
pulled up and away from the roof edge a few inches.
Prussick knots are amazing. They are best tied with loops of rope of a
size that is slightly larger than half of the rope size they are grabbing.
My safety rope is typically 11mm in diameter, and my prussick loops are tied
from 6mm cord. For tower work, I use these prussic loops to secure temporary
pulleys or lanyards to vertical masts. The prussick knot grabs so securely
that I can suspend my body weight from a smooth, 2" diameter, vertical
aluminum mast. yet, I can still adjust it up or down easily. This is how I
attatched the rigging to tram my beams up to my tower.
I also made a number of prussick loops from 0.075" kevlar cord with a
polyester jacket (this cord has a 500 pound breaking strength and is
available from Radio Works http://www.radioworks.com/crope.html ). I take a
6 or 7 foot long piece of rope, tie the ends together using a double
fisherman's bend to form a loop. I use the loops to tie prussick knots onto
antennas, mounts, coax, guy cables, etc and then clip the loop into the haul
line of the gin pole using a carabiner or quicklink to haul things up the
tower. I have even used these prussick loops to grab all three guys of a
tower, one loop per guy, to temporarily anchor guys while changing out
anchor hardware.
Here are some websites where you can see prussick knots in use:
Controlled release of rope (belaying
http://www.basarc.org/papers/roperescue/belaying.html
Anchoring a climbing rope:
http://www.basarc.org/papers/roperescue/anchoring.html
More information about my harnesses for climbing from the archives:
http://lists.contesting.com/_towertalk/199811/0653.html
Unfortunately my favorite links for sites describing techniques and knots
have broken. But there are plenty of other knot-tying site out there.
My favorite book on using ropes for climbing:
On Rope By Padgett & Smith
regards,
--...MARK_N1LO...--
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