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Re: [TowerTalk] Your experience with rope capstan hoists or winches

To: Steve Maki <lists@oakcom.org>, towertalk <towertalk@contesting.com>
Subject: Re: [TowerTalk] Your experience with rope capstan hoists or winches
From: Grant Saviers <grants2@pacbell.net>
Date: Wed, 13 Sep 2017 12:01:34 -0700
List-post: <mailto:towertalk@contesting.com>
?? I think I point out that self tailing (sailing) winches are a bad choice. And capstans are a good choice, particularly if they have reversing. Lot's of them in use as you mention.

Do the problems I mention never happen on capstans? The original post question was basically "what can go wrong using a capstan?"

Grant KZ1W



On 9/13/2017 11:05 AM, Steve Maki wrote:
Grant,

I can only say that if the sudden load movements and other undesirable occurrences you describe were common happenings in the tower industry using industry standard catheads, they would not be industry standard equipment.

The AB Chance catheads in particular were designed for the overhead line industry, and have been used safely for decades for installing pole transformers and HV lines.

I wonder what type of capstan you were using while sailing. It doesn't sound like the right gear for tower work.

-Steve K8LX

On 9/13/2017 12:28 PM, Grant Saviers wrote:

Years of sailing with winches large enough to pull 2+ tons taught me a few lessons about self tailing and hand tailing. Fortunately my or others screw ups resulted only in flailing sails, not the disaster that can happen with heavy vertical lifting. Although an out of control boom can be a lethal device as a friend was killed by one.

I would never use a self tailing winch for overhead lifting. While the grip systems usually work, "usually" is not safe enough. They are also sensitive to the size, type of line and its condition. Then the release from the self tailing mechanism requires actions which often cause a jump in the load part of the line. The person releasing the line is in an awkward position to control the line and has fingers close to the drum.

The person doing hand tailing needs to be thoughtful, alert, communicative, physically capable, and trained. Just as any other ground crew member. The functional problems I encountered with sailing winches were overruns, jams, and run-offs. An overrun is when a line gets under a turn nearer to the load (basically a half hitch knot). These can be very hard to safely or slightly release. A jam can happen when the turns get so tight together (or too many turns on the drum) they need hand massaging or a turn unwound to release and slip. Run-offs are when loops slip off the open end of the capstan and the tailing load jumps or becomes the total load. These are sometimes caused by the line handler not paying attention to the angle of the free line to the capstan, or jumps in the load.

Is a spool drum winch better? - it depends. Different kinds of jams occur for winches of the type used on vehicles and tractors (experience with this), which btw are not overhead load rated. A crane winch spools wire rope with perfect lays to not have those problems. Like my HDX589's feeder to the spool. However, working with wire rope has a lot of downsides for handling and rigging. Not the way to go IMO for amateur radio sized towers and loads especially with the rope technology now available.

The pro team that did my big tower used ropes and a capstan with power up/down. That capability with a good operator avoids the problems mentioned with lines on capstans. The loads were up to 350# antennas and controllable in less than a inch up/down. A convenient tie off on a cleat was on the winch mount and that was backed by a safety tie off. The tower sections weighed up to 1000# and went up with a crane. Although they had the gin pole and winch capacity for them the crane was faster, cheaper, and safer. For more than 25G towers and bigger than tribanders, I think these are the ways to go.

Grant KZ1W

On 9/12/2017 19:23 PM, Richard (Rick) Karlquist wrote:
I have been reading about how nice capstan winches are,
but I have no experience with them.  They seem very
dangerous since the line comes loose and the load
falls down in case the line handler's attention wanders
for a second. It seems especially dangerous to be
lowering a heavy load when the handler has to pay
out the line just fast enough, but not too fast.
A foot switch is suggested, but it doesn't work as
a dead man safety.  The winch stops but the line
still slips if not held back.

Seems like an accident waiting to happen, like free
climbing a tower.  Can someone with experience explain
how these capstans could possibly be safe?


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