When I had a crankup, "lowered" was still supported by the same single steel
cable as when all the way up, at least for my US Towers 89 footer.
Bringing it down was to a point where a limit switch stopped the motor. But
it was not "bottomed out" when fully nested. This is good, because the
tension on the steel cable wasn't changing dramatically in the fully
retracted position.
If the steel cable should part or slip significantly with your fingers or
toes between sections, the result could be injurious. Many suggest blocking
the thing off with big wood or metal pieces inserted between sections, and
usually we don't test the ability of the blocks to support the load without
slip. It could be risky taking the tension off the cable and then apply
tension again it when your task is complete. I'm not sure I'd trust a
relatively untested block any more than the steel cable.
I confess that I didn't usually bother, but I was always uncomfortable
climbing my nested crankup and felt much better when I was standing at the
top of the 20' or so nested tower. If you try to climb with your toes just
touching the outer section, it's not often enough "grip". I guess I could
have leaned a tall ladder against it and climbed that, it might have been
safer.
I feel much more comfortable climbing my newer guyed Rohn 55, even though
I'm climbing much higher. I've also learned the joys of "full body arrest
harness" rather than the old single Klein belt with one belt that I used to
climb with. It's slower and more fatiguing to constantly clip and unclip the
two shock lanyards as I climb and descend. But I'm now always tied off,
which reduces my chance of a fall should I make a mistake or I suddenly lose
function.
Tower climbing is hazardous. You make various choices to reduce risk.
Appropriate fall arrest gear is one choice, guyed versus crankup is another.
73 de Dick, K6KR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
Patrick Greenlee
Sent: Thursday, August 01, 2013 11:45 AM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Crankup Danger
Wouldn't you ordinarily lower a crank-up tower before climbing? If it were a
tilt over as well wouldn't you tilt it over instead of climbing it?
Patrick AF5CK
-----Original Message-----
From: Wilson
Sent: Thursday, August 01, 2013 1:22 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Crankup Danger
Well, if the tower should telescope while you are on it, the shearing off of
fingers and the front of your feet might be considered an undesirable
possibility.
If you are on an upper section when the collapse occurs, you might get by
with just some foot damage and being thrown to the ground as the section you
are on drops into the next one down...
Your plan is much like the old EZWay towers. There's a book for the two
section 40 footer on BAMA. http://bama.edebris.com/manuals/ezway/rbs40
WL
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