Should towbar recoveries be banned?

Agreed.

I dare say 90% of recoveries use the Reece hitch - me included, but there has been a few threads in various forums with people being outraged about a NATA a towball shackle on sale, yet I find it strange the same people seem to advocate SHOCK loading a non-rated mild steel pin in an assembly rated to a minimum of half the max loading for the kinetic strap in contrary to direct written instructions from the manufacturer.

I don't know.......you're either in the OH&S safety first boat, or not IMO.

A snatch strap used correctly is one of the most efficient, inexpensive, compact light weight pieces of recovery gear invented. Sensible commonsense recoveries done at moderate speed with the tow vehicle in low range second gear and the recovered vehicle assisting if possible will nearly always get the job done. Several small snatches are a lot safer than one huge high speed pull. It is important that the vehicles be in as straight a line as possible. An angle greater than 20% will put severe stress on even the stongest recovery point. I have seen a chassis bent when attempting a snatch from a chassis mounted recovery point at a 45% angle. Over the last 10 years as a nationally recognised instuctor I have demonstrated 100s of recoverys using the pin in a tow hitch and the above methods, I have never had any issues whatsoever or experienced a bent pin. My recoveries are done in a straight line with the recovered vehicle bogged axles deep in river sand on an uphill slope. I teach and reccommend this method to all my trainees. IMHO it is far safer with less margin for error than using a drag chain and shackles as a bridle which I have seen in some recoveries from the front of a vehicle. Always let practical commonsense be your guide if you have any doubts about the integrity of any component dont do it. Cheers Rob Berrill

Rob, I personally have no problems with the Reece at all and couldn't give a toss if it's legal or not. I know it works and works bloody well.

I am NOT advocating a ban, just putting up a topic for discussion.

i agree with what you say here rob.the whole toe bar on my old disco was fixed at 6 or 8 points , the pin being the weak link,(Hayman reece covering there perverbial) i f we are in fear of the pin tearing out and being a missile that can kill, use a cable break, as used in recovery with winches. this gives safety and will drop the pin and strap to the ground if such a thing happened and the pin came out.
cheers donnnnny

8 ton snatch straps break more or less at 8 ton force. The stretch factor of 20% is quoted at 50% force (4 tons for our example). Some snatch straps break at a lower, some at a higher force. The straps are 9m long. 20% relates to 1.8m, and assuming a linear spring constant in the elasticity of the strap, elongation, or stretch, will be 3.6m at a force of 8 tons.

Now F= k x s, where F = force (Newtons), s = distance (stretch) and k = spring constant.

Therefore k = F/s = 4000kg x 9.81 / 1.8m
==> k = 21800N/m

To calculate the stored energy and resultant forces in the snatch strap, we need to determine what the kinetic energy of the recovery vehicle is at the point where the snatch trap has enough force to stop it, ie at the point where the injected kinetic energy equals the stored potential energy in the strap.

The kinetic energy of the vehicle = 0.5 x m x v^2 (^2 = squared),
and the strain energy in the strap = 0.5 x F x s

Therefore, at v=17km/hr (4.72m/s), m=2300kg, and k=21800N/m,
the vehicle kinetic energy = 25644 Nm

Now, at this point, the strap strain energy = induced kinetic energy by the recovery vehicle

==> 0.5 x F x s = 0.5 x m x v^2

==> s = sqrt(m x v^2 / k) = 1.53m stretch

Therefore, the force exerted is
F = k s = 21800 x 1.53 = 3.41 tons.

In other words oops can be produced using the towball.

Yep I knew that all along. :-)

LOL....didnt say it would be oops said it can be. And I am just as guilty of the slip it over the ball to pull through sand as any one else.

Ahhhhaaaa...........but F=ma so a 3.5 tonne 4x4 accelerating at a slightly higher rate will increase the force significantly and not forgeting the half mv squared factor either!

Is that not so?

The prosecution rests;-)

This force assumes that the snatch strap has a 20% elongation at 50% load. Tests have shown that some snatch straps only have 15% elongation, which would mean that for these the exerted force would be 4.5 tons instead of the calculated 3.41 tons. If we add a V8 at the same vehicle mass with a higher speed to the equation, the forces will be much higher.

But as a cure for boredom on a monday night equations are a tad of fun as you can make them say much what you want.

At this stage the prosecution calls for an adjournment until he can remember more of his high school physics lessons.

I knew it would come in handy one day!

Nah...Common sense prevails most of the time and you know what your vehicle is capable of. Just thought I would see if it was possible to work it out. There are so many variables, rust, fatigue, heat and how many beers have been consumed.

Hey Oldsquizzy, is that dairy on the road to Ivanhoe still making those deluxe banana milkshakes? Lived in Kunnunurra for a while and they were a real treat. Picked melons and then got a real job at Oliver Ford as a mechanic. Great memories but it would have to be 17 years since last there.

And the Bridbangbidilyongtongbangbong bar and the Hotel Kunnurra 'Sportsmens's Bar'. The Four Star Cafe.

Do the Youngs still run the town?

Had a couple of wooblahs tonight myself as a matter of fact, might be beddie byes for me.

Yeah you can still get milkshakes and the Birchs are the ones to watch around town nowadays and the hotel is still going strong

True to a certain degree, but in thick mud for example or below the water line in the ocean situations I could easily imagine the forces being huge. When they get stuck down to the gunwhales, man do they get stuck.

Yep V8, I had 2 brocken snatch straps and $2500.00 damage to a strangers car (which of course I organised the repairs and paid) to boot in that scenario....won't go anywhere without the high lift jack again!

Cheers Andrew

I think you have a pretty strong point there Peter.

Before I read your reply I was thinking about asking the same question.

Cheers Luke

Righto.

That'd be why all the army Landrovers, Acco's, Unimogs, Macks etc etc etc have winches then?

Main reason for said winches is that the tactical situation sometimes demands going where you shouldn't really go ;-) Using a winch is often the quickest way out. Can also be used to haul heavy loads (artillery pieces etc) into position.

>>Memorable words of Army Driving Instructor to trainees during off-road training course c1966

and as stupid today as it was C1966...

Truckie, your turn to stir the pot now.

Over to you.

You mention rated hooks and recovery point and that many clubs insist on these ratings, but how many are correctly attached to the vehicle and then certified for that load rating? So unless people have had these hooks load tested and certified after fitting them they should not be pointing the finger at anyone.
Chris

Another good point Chris!

Willem, I agree with you 100% but my point was to raise this as a discusion topic following on from the recent bullbar and towball shackle threads.

I've done many, many non-rated recoveries (what did we do 20 years ago???) to the extent of pulling 6 wheeler trucks and tractors out and just exercised common sense (it's got me this far) without too many dramas (touch wood). I don't consider myself the anti-christ for doing so either, but some folks would call for me to be burnt alive at the stake for doing them, yet in the same breath happily do what appears to be exactly the same thing from a Recce hitch. I find it surprising some clubs advocate leaving bogged people if they don't have rated points as well.

I'm not advocating it, I'm interested in the responses, that's all. I may have missed something glaringly obvious too which is highly likely.

(BTW see my response to re: the 'clubs' question a few hours ago too;-)))

OK Karl... didn't mean to hi jack the principle

DON'T USE TOWBALLS AS ANCHOR POINTS FOR SNATCHING.........LOL

Satellites Willem, satellites.

They can spot anything nowadays.

and don't forget the miniature electronic bugs in your fillings.......

Ill Police it Willem,

The Rules.
1. If you want to you can, if you get hurt its your fault.
2. If you dont want to you dont have to therefore it doesnt concern you.
3. If you see someone else doing it, move away.

For those who regulary say there needs to be a law for everything and no laws should be broken, follow the above rules and you will be alright. If you found yourself to be breaking one of the rules post a $100 cheque to :
Hairy
Po box 6546986583
Alice Springs
0871
and your concience will be clear

Cheers

Hairy,

The last thing we need is an outbreak of common sense in these types of debates!

Shame on you. Fine yoursefl $100 dollars and do not pass go.

Matt.

Cheques in the Mail!! LOL
Cheers

So you'd say using 1. overloaded 2. non-rated recovery points directly against 3. written manufacturers instructions would be OK as there hasn't been a precedent set?

Would you class the above as a 'recognized recovery technique'? If so, by whom?

Care to stake your house on that?

Once again I point out I personally don't give a rats, just playing devil's advocate here.

How do you know they are overloaded if they are not rated?

I'm saying my vehicle manufacturer has tested them using the same equipment i use ie. towbar, so i am happy with the equipment. Using a genuine towbar in my case, and referencing the vehicle manufacturer as saying that it is safe to recover using the towbar, not the towball incidentally (opens up another thread :-)), is my defense....and i will bet my house on it in this case.

I wouldn't bet against a manufacturer (towbar or vehicle) if forced, however who would win if pitted against each other in a court?

BTW i have never seen any written instructions from the manufacturer of the towbar, only from the vehicle manufacturer......sort of a genuine v's after-market issue in the case i mention.

Thanks for playing devils drinking partner.

Andrew

Mike, it honestly don't worry me none - I'm just playing devils advocate (as I'm prone to do) and raising a topic for discussion.

I endorse risk taking behaviour in this sterile and cotton wooled, nanny state society we now have to live in.

There is nothing wrong with a little pussy - a friend of mine has two small kittens.

It would only apply where it happens in a workplace which is a place where paid work is occuring

Yeah I know that, joist pointing out that a lot of thighs we do when 4WD doesn’t comply with safety standards or procedures

Exploder, was that a Freudian slip; 'a lot of thighs' after reading Mr Harding's comment about a little pussy?

Could have been, but I would ahve to say I don’t like pussy bolted to a chassis rail.

We should meet for a beer jack :)

Hi Mike:

Now that is one thing I know would be an absolute pleasure :)

Jack

Would that beer drinking arm be legally load rated though?
And what is the rated duty cycle of said arm as per the manufacturers specs.

Jack, you can't go spouting common sense ideas like that; society is not ready for it!

I'm still waiting for the flaming poo nazi to leap from behind a behind a bush and appraise combustion of the bog roll and hole depth when I'm next laying a cable or the Stalin of tyre pressures to chastise me as an eco vandal for not dropping my pressures 2lbs on the Paynes Find to Sandstone gravel road.

Welcome to our campsite Bware, plenty of room here and getting quieter by the day;-))))

Mog?

here is a pic with the 28" extension mounted
with the weight distribution mounted I can tow 12,000lbs at 28" extended from
the tow bar
have fun

http://www.ozshops.com/P1110012.JPG

gmd

damn keyboard 0418904057

Okay if some wants their Hayman Resse set up without tow ball Their risk. I 'm for rated recovery points but lets not ban everything

Wasn't advocating it, just some food for thought.

It's D.I.L.L.I.G.A.F. for me when out bush;-)))

Now if you could hit a bush turkey with a flying towball...mhhhh....now there is some food

But wouldn't the turkeys be 'busted'?

busted , basted, who cares still be nice