Towing out snowed in cars - a cautionary tale!

On or around Wed, 04 Feb 2004 14:51:25 -0500, Mike Romain
<[email protected]> enlightened us thusly:

>I have a Warn XD9000i winch with 125' of 5/16 or 8mm aircraft wire rope.
>
>It is rated at 9000 lb or 4080 kg for a single pull (another site has it
>rated at 9500 lb single pull) and the wire rope has a 4773 kg or 10500
>lb breaking point.

which is considerably under the 19000lb or so you reckoned to pull with it.
Bit of luck those figures they quote have a built-in safety factor then,
isn't it. a bit like the ones for ball hitches, I expect.

another point - how do you attach straps/harnesses etc? what's the safe max
load of the shackles etc. you may use?


--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"My centre is giving way, my right is in retreat; situation excellent.
I shall attack. - Marshal Foch (1851 - 1929)

On or around Wed, 04 Feb 2004 08:44:52 +0000 (GMT),
[email protected] ("David G. Bell") enlightened us thusly:

>The Land Rover has a NATO tow-hook bolted to the frame, but I understand
>this ancient design couldn't be sold as a new vehicle in the US.

your loss

besides, I think they do, they must have exemption.

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"You praise the firm restraint with which they write -_
I'm with you there, of course: They use the snaffle and the bit
alright, but where's the bloody horse? - Roy Campbell (1902-1957)

On or around Wed, 04 Feb 2004 14:01:39 -0500, Mike Romain
<[email protected]> enlightened us thusly:

>These are bolted onto the frame with high grade bolts.

if you mean high tensile bolts note that they're not much better in shear
than mild steel.

the pin on the sliding hitch on the back of our disco turns out to be mild
steel, if overloaded it's more likely to bend than to snap. Apparently. I
made an adapter to mount NATO hitch at bumper height, which uses 2 such
pins, and I've towed about 3-and-a-bit tons on it.

The hitch is probably rated to tow 3.5 tonnes, on it's original single pin.
Not that I really like the design, mind.

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Soon shall thy arm, unconquered steam! afar Drag the slow barge, or
drive the rapid car; Or on wide-waving wings expanded bear the
flying chariot through the field of air.- Erasmus Darwin (1731-1802)

I have that same warn winch.

Here's what I found out about the cable/winch rating when before I
bought it.

The cable is rated at,let's say, 9000lbs. that means that you take that
cable and attach it to "something" secure and an object weighting
9000lbs can hang from it (not moving). (it doesn't mater if it is a
Jeep, Landrover, any other car or your mother in law).

The object is supposed to be in rest (not moving etc) and then basically
the cable can withstand a force equivalent to 9000lbs hanging from it.

Pulling "whatever" with the cable usually means it is not in rest and
other forces etc come into play too. This means that on some occasions
you can move a 10 ton tree with it without a problem or you might be
able to get a train moving and the next time however a 1 ton passenger
car might snap the cable.

The winch cables are rated at a constant force in a straight line.
that's it. if it exceeds the rating it might/can snap, if it doesn't
exceed the rating and the cable is in good condition it is not supposed
to break when the force is applied in a straight line.

When using leverage (blocks etc) it might be easier to pull things
(meaning it is easier to generate a higher force at the other end of
the cable, the winch just has to "work" longer) BUT it is also easier to
go beyond the rating of the cable.

The XD9000i can "pull" the cable using a force equivalent to 9000lbs
hanging (on a cable) in rest. The cable that comes with it is rated to
withstand that force when it is in good condition.

When winching, one of the rules of thumb is that when something isn't
moving towards the winch, and you keep pulling...it might get dangerous.
(I have seen a hitch break, hooks and bumpers fly)

But I must say, that XD9000i pulls pretty good size stumps.

No I don't sell Warn winches, I just got informed a bit by them before I
bought it.


Ron


Chris Phillipo wrote:

>>>http://www.warn.com/truck/winches/src/XD9000i.shtml for the winch.
>>>
>>>And for the wire rope specifications, see:
>>>
>>>http://www.warn.com/industrial/winches/series6hyd_pn33445.shtml
>>>
>>>Not the same winch, but the same rope I think.
>>
>>Thanks. Please don't think I'm being deliberately provocative, but the
>>safe working load of your wire is less about one ton/tonne:
>>
>>http://www.tiedown.com/winch.html
>>http://www.airwinch.com/tools/wireropechart.htm
>>
>>
>>
>
>
> Or try http://www.winchtest.com/, they fail at about 8500lbs. However
> to actually generate 9000 lbs. of pull on a winch rated for that you
> will only get it on the first wrap of the drum, which means you'd have
> to let out 125' of cable to do it. People rarely do that. Besides,
> with a snatch block you can safely go to 16,000 lbs. And if you are
> more stuck than that you are leaving the truck there for archeologists
> for find in 200 years.

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Mon, 2 Feb 2004 18:06:39 -0400, Chris Phillipo
> <[email protected]> enlightened us thusly:
>
> >And you think the two bolts holding that are rated for 3.5 tonnes?
>
> probably, they (should be) 16mm high tensile.
>
> gives you a combined CSA for both of around 400mm²
>
> ISTR that mild steel has a tensile strength of about 16 tons/sq.in, which
if
> my calculations are right means that 2x16mm mild steel bolts would have a
> tensile strength of getting on for 10 tons. High-tensile ones are apt to
be
> stronger, at least in tension... The NATO hitch on mine is fitted by
4x12mm
> high-tensile bolts which have a combined strength slightly higher than the
> 2x16mm ones.
>
> meanwhile, the neck of the towball is somewhat larger, without measuring
it
> I don't know what size it is, but I'd hazard a guess that it's at least
20mm
> which makes it the same area as the 2 bolts, it might be slightly larger.
>
> I'd have to look up shear loads.
>
> However. the tow ball is rated to tow 3500Kg, and even on-road, the
dynamic
> forces exceed the static load (e.g. from over-run braking), I'd be amazed
if
> the tow ball hasn't got at least a factor 2 in its design, probably more.
>
> Obviously, you can break it, you can break anything. But I don't think
it's
> common, and I don't think it's as puny as you all make out.
>
> ISTR a common size for shackles is 3/4" - that pin is probably not as
thick
> as the neck of a tow ball.
>

Most of the seious offroaders around here when going on a trip undo the
towball any way and take a extra high sheer force shackle. slip the U though
the loop in a snatch strap, and the pin through the hole where the towball
goes in the bar, and do up. I'd have to crawl under my Trooper/bighorn to
have a look to count the bolts or welds, but It would have to (by law) be
attached by welding (strong) or high tensile bolts (also strong ) to the
frame of a framed vehicle. I'm not sure about monocoque bodies.

rhys

In message <[email protected]>, Mike Romain
<[email protected]> writes

(cross posted on purpose)

>I don't know about him, but I have short straps that can wrap around a
>frame to give an anchor point if the vehicle isn't equipped with a tow
>hook or ring bolted to the frame. My long straps are rate for 30,000 lb
>and I think the short ones are the same. My straps have sewn loops, no
>metal to fire off.

I have been lurking with interest up to now but as I own and run my own
vehicle delivery and recovery business I'm afraid that I am going to
have to say something.

Webbing straps/strops ARE NOT designed to be wrapped around ANYTHING
(except tree strops with a protective sleeve). They are designed to
pull in a straight line with no fouling. You start wrapping around
chassis and you are reducing the 'safe working load' of the strap and
NEVER NEVER re-loop itself back through one of it's loops as this could
multiply the strain on the part of the strap going through the loop,
always use a shackle of suitable strength and quality for the job.
Always use one with a safety certificate so if there is any malfunction
you may have a 'possible' claim. My insurance runs into thousands and
as part of the health and safety/insurance are concerned my equipment
has to certified and checked at regular intervals. As regarding using
kinetic ropes, please, if you have never used one of these before be
careful and always read the instruction first, they are there for a
reason. They can be lethal if not used correctly.

--
Graham Jones

WOW!!! HOW MANY REPLIES!!! GOTTA BE THE MOST I HAVE EVER SEEN!

MC

------



"Chris Phillipo" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, orygunguy2001
> @hotmail.com says...
> > You may want to bash American's but when you need us to save your sorry
ass
> > we will!
> >
>
> We don't have any oil, go away.
> --
> ____________________
> Remove "X" from email address to reply.

Try Rec.Scuba.... they really go overboard... 4000 posts in one thread in
the archives


"Mark C." <[email protected]> wrote in message
news:d_aVb.2625$q%[email protected]...
> WOW!!! HOW MANY REPLIES!!! GOTTA BE THE MOST I HAVE EVER SEEN!
>
> MC
>
> ------
>
>
>
> "Chris Phillipo" <[email protected]> wrote in message
> news:[email protected]...
> > In article <[email protected]>, orygunguy2001
> > @hotmail.com says...
> > > You may want to bash American's but when you need us to save your
sorry
> ass
> > > we will!
> > >
> >
> > We don't have any oil, go away.
> > --
> > ____________________
> > Remove "X" from email address to reply.
>
>

Graham Jones wrote:
>
> In message <[email protected]>, Mike Romain
> <[email protected]> writes
>
> (cross posted on purpose)
>
> >I don't know about him, but I have short straps that can wrap around a
> >frame to give an anchor point if the vehicle isn't equipped with a tow
> >hook or ring bolted to the frame. My long straps are rate for 30,000 lb
> >and I think the short ones are the same. My straps have sewn loops, no
> >metal to fire off.
>
> I have been lurking with interest up to now but as I own and run my own
> vehicle delivery and recovery business I'm afraid that I am going to
> have to say something.
>
> Webbing straps/strops ARE NOT designed to be wrapped around ANYTHING
> (except tree strops with a protective sleeve). They are designed to
> pull in a straight line with no fouling. You start wrapping around
> chassis and you are reducing the 'safe working load' of the strap and
> NEVER NEVER re-loop itself back through one of it's loops as this could
> multiply the strain on the part of the strap going through the loop,
> always use a shackle of suitable strength and quality for the job.
> Always use one with a safety certificate so if there is any malfunction
> you may have a 'possible' claim. My insurance runs into thousands and
> as part of the health and safety/insurance are concerned my equipment
> has to certified and checked at regular intervals. As regarding using
> kinetic ropes, please, if you have never used one of these before be
> careful and always read the instruction first, they are there for a
> reason. They can be lethal if not used correctly.
>
> --
> Graham Jones

You are correct Graham!

I normally throw away the short straps that were used if they got ripped
pulling the stuck vehicle if it was wrapped around sharp points.

I live in Canada though.....

This is a serious rust belt in central and southern Canada, nasty rust
belt!!!

I use the straps in a loop, couple feet, loop, couple feet, loop, couple
feet, loop idea to spread out the stress.

I then have also just up and cut off the damaged ends and used a tied
loop.

Yes I know the knot is a weak point too, but am aware of it.

Same as someone else pointed out the 'working load' of my winch cable
isn't the best. I know this and watch my ass.

I also off road a whole bunch so take wear and tear on gear and vehicles
as a matter of 'you play, you pay'. ;-)

Here are some photo albums from my of road trips. I organize trips for
the central Canadian bunch from a Jeep newsgroup,
rec.autos.makers.jeep+willys.

Canadian Off Road Trips Photos:
Aug02 http://www.imagestation.com/album/?id=4291402603
June 16/02 http://www.imagestation.com/album/?id=4291718705
Easter/02 http://www.imagestation.com/album/?id=4291929351
Jan/02 http://www.imagestation.com/album/?id=4292141347
Aug/01 http://www.imagestation.com/album/?id=4292076845
Day Trip Misc. http://www.imagestation.com/album/?id=4291902217
CJ build http://www.imagestation.com/album/?id=4292105877
Jan03 http://www.imagestation.com/album/?id=4290887779
Aug 03 http://www.imagestation.com/album/?id=4289239511

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

: Here's what I found out about the cable/winch rating when before I
: bought it.


You left out one of the most important bits of information - the
winch rating only applies to the first layer of cable on the spool.
In other words you get maximum pull strength if most of the cable is
pulled off of the spool and you are down to the first layer.
The outer layers can't pull as strongly because the diameter
of the spool is effectively increased thus reducing the pull.

[email protected] wrote:
>
> : Here's what I found out about the cable/winch rating when before I
> : bought it.
>
> You left out one of the most important bits of information - the
> winch rating only applies to the first layer of cable on the spool.
> In other words you get maximum pull strength if most of the cable is
> pulled off of the spool and you are down to the first layer.
> The outer layers can't pull as strongly because the diameter
> of the spool is effectively increased thus reducing the pull.

That is why a pulley block is recommended. It gets more off the spool
and halves the load on the wire.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

That's true, as any other rating, certain conditions are assumed.


[email protected] wrote:
> : Here's what I found out about the cable/winch rating when before I
> : bought it.
>
>
> You left out one of the most important bits of information - the
> winch rating only applies to the first layer of cable on the spool.
> In other words you get maximum pull strength if most of the cable is
> pulled off of the spool and you are down to the first layer.
> The outer layers can't pull as strongly because the diameter
> of the spool is effectively increased thus reducing the pull.
>