From: amirza@bronze.ucs.indiana.edu (Anmar Caves)
Subject: Re: Tow chains or slings?
Organization: Indiana University
Date: Wed, 16 Dec 1992 18:55:56 GMT

In article <122980022@hpfcso.FC.HP.COM> byrnes@hpfcso.FC.HP.COM (John Byrnes) writes:
>>	In terms of winches, yes they would be very nice and yes they are very
>>	expensive. A good intermediate solution is a hand winch. I have one
>>	I bought for $50 that can straight lift 2,000 pounds. That means...
>
>Hmmm.  Considering all the dangers cited about this, it seems weird that
>people are recommending hand winches.  Am I missing something?  
>
>Seems to me that in order to operate a hand winch, you must be standing 
>next to it -- the prime "target" area if something blows.  

As we all know, shit happens.  The come-along is one of the most
versatile pieces of equipment you can pack, and it has the advantage
of working when the truck engine isn't.  Yes, it is dangerous to be
anywhere inline with the pull, but with proper operation it can be
made fairly safe.  Typically, with a come-along, I wouldn't work with
anchor to vehicle distances than say 20-30 feet unless a longer pull
was my only option.  If I tried a 100' pull even with my static rope,
the stretch potential can take up a significant amount of the overall
pull, making for a lot of extra work.  Forget it with the dynamic
rope, it stretches too far at that distance.  Properly  done, with a
hand operated winch, the operator is in the middle of the pull, and
there are no heavy objects that the rope is tied to that could come
loose and fly towards the operator.  The reason that we're stressing
not standing inline with the pull is that invariably someone is gonna
tie the damn rope to the ball hitch on their bumper.
>
>*********************
>In regards to my post about using a climbing rope:
>
>Sure, the stretch of the rope stores energy, BUT the rope has a very small
>mass (F=MA), so even if it breaks, it probably won't seriously injure you
>(unless it brings something with it).  So I echo the discussion of being
>aware of what you tie it to.

The problem here is time.  A static rope has stretch to it, quite a
bit in fact, sometimes up to 15% before breakage.  But, if it breaks
it expends all that energy quickly, and mostly right at the point of
breakage with the rest being absorbed along the length of the rope.
A dynamic rope has a hell of a lot of stretch and may stretch up to
50% before breakage, this leaves a lot more energy for the whole rope
to dissipate, and it does that by snapping back with a *lot* more
force than a static rope.  And *never* underestimate what that rope
will do when it breaks.  You don't read it right and it'll bite you
for sure.  That's from experience with both static and dynamic ropes.

>My personal opinion and experience tells me that the stretch is an 
>advantage to static ropes, chains and straps for pulling vehicles (not
>pulling stumps, etc).  Your milage may vary.

My whole point in the original post was that if you're gonna do short
pulls then it doesn't really matter what type of rope you use, static
or dynamic, but if you're going to store the capability to do a 150'
pull then you're much better off using a static rope.  Static rope has
enough stretch to do the job, but not so much as to make the
possibility of getting bitten prohibitive.  If dynamic rope works for
you, then great, and I wish you success, but when I'm making a
recommendation to someone who is starting out with this, I'll stand by
what I say, not only as opinion, but as experience reaching far beyond
winching vehicles.

-- 
Anmar Mirza   # Chief of Tranquility  #My Opinions! NotIU's!#Purveyor of
EMT-D         # Base, Lawrence Co. IN # Legalize Explosives!#nontraditional
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