A potentially dangerous recovery situation - and a lesson learned

We used it for many many years, until I read about it on this site a few years back.

Just for those who have not heard the why.

Tow balls fracture and become a great missile.
Several people have been killed.

There was a boke a few years ago in NSW who was on his tractor being snatched out by his wife in the 4wd.

The tow ball broke and he copped it straight in the head....killed instantly.

Imagine the state his MRS would have been in.

DONT use a the tow ball foe anything other than towing...please.

cheers

I would firstly ask what recovery point did you use that broke.
I assume that it was not rated bolts in it.

Yes there are many un uneducated people out there only too eager to throw a snatch strap on and go like the wind.
Please please people if someone tries to hurry you along with a recovery stand up and say something to them. I know it can be confronting but when lives can so easily be lost its not worth it
Never use a snatch strap in poor condition and certainly NEVER NEVER
use a tow ball. The pin in a Hayman Reece style tow bar with the pin through it is my preference for a recovery from the rear. Front recoveries I have two rated recovery spots and use a bridle and a snatch strap attached to the bridle.
You did the right thing by trying the Max Trax first and I think if he had driven properly then you may have succeeded.
Most 4x4 clubs have a driver trainer who will teach you free of charge how to snatch safely. I urge everyone to become trained in how to safely do this
Cheers
patrolman

What are:-

RPL
Stall stop hill recovery?

Phil

Recognition of Prior Learning

A stall stop hill recovery.

Is where.....when negociating a steep hill, it all gets a bit much and either the vehicle will not make forward progress OR there is a danger of the vehicle overturning or some such.

In simple terms, while the vehicle is still running in gear, you press on the brakes hard ( real hard)and stall the engine....leaving the clutch, accelerator and hand brake alone

Leaving the foot hard on the brakes, reverse gear is selected.... it is usual that the vehicle is already in low range.

the brake is released and the engine started with the vehicle in gear and allowed to idle down the hill under compression braking in reverse gear.

Until you have done it a couple of times it all seems very bazzare, BUT, it is considered the best and safest way to get off a very steep hill backward and with the wheels closest to the ground...and yes it works very well.

BTW, it can be done forward too.....if you have a holy crap moment and need to stop going down a hill...assuming you have a reasonable proposition of actually stopping......you can stop and start again leaving the vehicle in gear......but forward its arguably better to squeeze the brakes on the stomp on em..
Its does not work as well down hill as it does up.

cheers

Stall stop does work well for a manual but is not suitable for automatics.
Regards Andrew.

Sorry but it is entirely suitable for automatics, BUT, the procedure is different and you have to know how your particular automatic will react.

With an automatic you may not stall the engine and instead of restarting and idling down the hill. reverse is selected and you drive thru the brakes.

In general, reverse is selected and the brakes are eased off until the car moves at the desired rate....depending on the vehicle some throttle may be required.

It is most important with automatics to practice, particularly with some modern vehicles that have nanny like control systems.

In some autos, it may all be unnesessary, because hill decent works in reverse in some vehicles.

The principle of stopping the vehicle with the brakes while in drive and holding with the brakes while reverse is selected AND driving the vehicle off the hill under power rather than rolling down out of gear remains the critical part.

If you say it does not work with autos...sorry... I have seen it done as part of assessments for the nationally accredited training course....several vehicles, several times.

cheers

That makes no sense at all
Why put it in reverse?
If its in low range many 4bys wont move on compression
If your going down the hill let it crawl down
Doing it undet compression with reverse selected is shocking advice
It could lock up and just slide
Who the heck taught you that?

Sorry I misread. Your talking about reversing back down a hill after not making it up
Yes that's how I was taught

Sorry Bantam, whilst I agree with you on the fundamentals of driving through the auto as the best method of going downhill "slowly" in an auto it is not and never will be a stall/stop procedure.
I never claimed to reverse downhill in neutral merely pointed out that a stall/stop isn't applicable to automatic vehicles.
And yes, I am well aware and proficient at left foot braking and driving through the auto in situations requiring slow descent in downhill situations.
Regards Andrew.

You are correct in that some of the knobs were removed from my recently purchased Maxtrax. The annoying thing was that the tyres had left rubber on the flat surface of the Maxtrax indicating that the system was working. I was shouting at the guy all the time to ease off on the accelerator but he falsely claimed that the vehicle was on the verge of stalling without the extra revs.

The recovery point was rated at 4.5T so I thought that would be sufficient. Inspection has shown that part of the tow bar was secured by the recovery point bolts. I suspect the bolts used during the fitting of the tow bar were not those originally associated with the recovery point.

4.5 tonnes is insufficient by a long way for snatch recoveries.

As I mentionen further on, most of us carry either 8, 10 or 12 tonne minimum breaking strain snatch straps.

The 8 tonne for the light vehicles like hiluxes and prados and the others for heavier rigs.

The standard hook recovery point that is very commonly used is rated at 10 000 Pounds or around 4.5 tonnes. Because it is not regulated lifting equipment and there is no qualification to the rating it has to be assumed that that is breaking or failure load. Perhaps with a small safety margin, may be 20%.

They do fail, quite a few people have bent or broken them.....mostly they straighten out, but sometimes they fracture.

Experience in the 4wd industry seems to indcate the rating is a fair thing.

It is important to understand that we must dictate what is going to break, if ( no when) it does.....and we want the snatch strap to break and nothing else, because that is the lowest risk and the easiest risk to manage.

So for any sort of snatch recovery we should be using two of these recovery points with an equaliser strap.

We have ratings for the recovery point its self......but how about the attachments....AAAAHHH.

If the recovery point is attached directly or near directly to the chasis with high ternsile bolts as big as they should to fit the point
and the have full depth of thread in the nuts and the load properly distributed and crretly tightened.....they should achieve the rated performance.

cheers

This in my opinion is the best snatch and flat towing option. Better than 5 kilograms of solid steel with a kilo 'U' bolt hanging off it!

Micheal why do you say it is better than the traditional solid bar type?

Looks good to me BTW

Michael, I have always taken the tow bar out and put the pin through the eye of the snatch strap - if the pin snapped that is the only thing to become a projectile. Is there any reason it shouldn't be used in this way - a dedicated recovery point held in with the pin, or your tow / snatch hook is still a potential projectile?

Alby! Just from the point of ease of attachment of the snatch strap and lighter weight than those solid bars you see hanging off every second 4x4. If something does break with those solid bars, it's a hell of a projectile! And Drew yes I have the same opinion about the pin breaking but for a compromise ,I think it's a great idea . It's from a guy on the Patrol forum , screen name is Ray! I've tested it and it works great! Michael

Agree Michael that it would be easier to attach your strap too, I have not seen one of those before

Drew by just using the pin you are applying more leverage to it than the guillotine like shear forces that the pin is under with a recovery or towbar hitch. Not saying whether it is strong enough or not but under extreme test load it would fail first

Alby! I was going to mention about the shear either side of the pin, rather than the strap sitting in the middle of the pin but I guess if the pin did give way with just the strap on it, the pin halves would stay and just the strap would recoil! So if snatching safely, no personal harm would occur! That's why I didn't go into it but it is a valid point! Something other than just the pin would be stronger. Michael

I agree with your comments. I had the recovery equipment for MY circumstances and didn't consider the possibility of helping others during the trip planning. In hindsight I should of taken control of the motorhome and used minimum power to get the thing moving.

When the other guy wanted to use the snatch strap I should of just stood back and let him do the recovery. Point was he didn't want to use his own vehicle and I wasn't going to leave two elderly ladies in a remote location.

Yes Brian, sometimes when we get other intervention, our original plan is clouded. Later we realised the first plan was the best. Michael

While using the pin only in a hitch receiver type tow bar is reasonably safe and a good choice if there is no other option BUT there are several issues.

Firstly under no circumstances is the 1/2 inch pin going to shear, unless it has been replaced with something that is way weaker than supplied with the tow bar or has been damaged.....not with just the strap, not with a purpose made hitch in the reciever.

This is the opinion of engineers in both the towing industry and the recovery equipment industry.....and I have checked it my self.

The most common problem is the pin bending.....this is far from uncommon. The hitch pin was designed to operate in shear, not with the load concentrated in the center like a strap does.

It is far from uncommon for the pin to bend so badly that it can not be removed and the snatch strap remains stuck till the pin can be driven or cut out.
Do a proper job of bending the pin and you have to cut it inside the hitch, sometimes both sides.

The second issue is that the rerciever its self presents chafing points along all 4 edges of the tube. I have seen near razor sharp edges on some recievers that have had a hard life.

Third, that half inch diameter of the pin is toward the lower end of the diameter that the loop of the strap should be carrying load on.

A properly constructed hitch reciever recovery point is by far a better option.

It is more likely that the whole tow bar will come of the vehicle before the pin shears.
If you are doing the calculations yourself, remember there are two shear points....thus twice the shear strength.

While someone may have enginered the t bar recovery point above. My strong preference and the strong preferance in general is the solid machined bar with a large rated bow shackle.

the advantage of these is that they accomodate off angle trusts well, in two planes.
In addition the shackle is what straps are designed to terminate on and will result in no reduction in strength at the attachment point.

Now, this brings up a complicated issue....how different things are rated.

Because there are so many different rating systems in play we have to resolve everything to minimum breaking strain.

Now, most of us will be carrying 8 or 10 tonne minimum breaking strain snatch straps, some may be 12 tonne.

For most light 4wds like hiluxes & prados an 8 tonne strap is appropriate.
AND 8 tonne minimum breaking strain is exatly that, when the strap is new.

The rated lifting industry shackle in my recovery hitch is rated at 4.7 tonnes Working Load Limit(W.L.L.), standards and federal laws require that it must have a safety factor of at least 4:1. That gives it a minimum failure load of 18.8 tonnes ( under the regs any sort of distortion is failure). Most reputable manufacturers far exceed the safety factors in the regs, most claim at least 5:1 the better manufacturers up in the 7 & 8 to 1.

The shackle is not going to break

For most people bar far the best option for a rear recovery point is a properly designed hitch reciever recovery point with a large bow shackle.
A reputable item can be had for around $50.

cheers

In using the rated recovery gear cioncept the rating of the lowest item in the system means that its rating is the lowest for the system. In the above system the tow bar itself will have a max rating of 3500kg (maybe less) so really this makes the whole snatch system using a tow bar is 3500kg - too low to snatch safely.

People quite rightly go on about the ratings of snatch straps, shackles etc but ignore the low rating of the tow bar - if you follow the rating philosophy you must also take into account the rating of the tow bar - no different to the rating of a dedicated rated recovery point bolted to the chassis.

Garry

System I use on the back of the 40. Of interest, the tow-bar is both bolted to the upper frame and welded to the lower frame.

Again we have an item with a different rating system.

The tow bar is rated for towing a 3500Kg maximum, ATM, this is not its minimum breaking strain or failure load.

It's rating is very different to the rating on a dedicated recovery point attached to the chasis.
It is clear that the rated recovery point has a rating of 10 000 pounds around 4.5 tonnes, for the purpose for which it was Designed and for which it was labled.

In fact it is not necessarily the towbar its self that is rated, the rating stamped on the tow bar is that which is permitted bassed on a series of factors in particular the rated towing capacity of the vehicle.

If you go and look at ADR 62/02 Mechanical connections between vehicles.

In simple terms.
It requires a minimum tested static longitudinal tension and compression of at least 1.5 times the Agrigate Trailer Mass for which the tow bar is rated.

Plus a number of other factors specified in the standard.
Including repated dynamic loadings.

In practice properly designed installed tow bars are much stronger than required by the ADRs.

AND

The matter has been discussed at length in detail between the 4wd associations, the recovery equipment manufacturers and the tow bar manufacturers.

The considered view is that if the vehicle is fitted with the maximum permitted towing capacity towbar for the vehicle it should be safe to snatch with it.......AHH...... provded that the correct rated snatch strap is used for the vehicle mass.

On a practical level.
I have two standard 4.5 tonne recovery points on my vehicle front and rear they are fixed with the appropriate high tensile fasteners two in each point.
I expect these points to perform as rated.
My rear tow bar is fastened with 6 similar sized bolts, 3 each side.
In addition the design of the bar positively locates it against the chasis to deal with rotational forces due to the leverage of the bar.

I estimate that in straight line pull the towbar is 50% stronger than both recovery points conbined.

In fact I expect the chasis will bend before the towbar or its attachment fails, because, I have seen the very same model rear ended, towbar straight & in tact, but the chasis well bent.

OH Yess it has been known for tow bars to fail during snatch recoveries.

In most cases the tow bars in question where either low rated non hitch reciever type tow bars or there were issues with the attachment of the towbar.


Garry mate its good that you are thinking of these things...they need to be discussed and braught to peoples attention.

all too often people are just blindly ignorant.

There is also the issue of alternatives.
For some many, due to the design of the body work and access to the chasis, the hitch reciever in their tow bar is the only practical recovery attachment to their chasis.

cheers

I agree with everything you have said - and indeed I use my tow bar as well for snatch recoveries using an appropriate receptical in the receiver hitch but as the bar does not have a rating (even though I know it will be strong enough) for recovery then in theory it should not be used until a recovery rating but a competent authority is determined.

As I said - in theory.

As a side issue - we talk about not snatching from towballs and that is how it should be but if you have a look at a few of the official incident reports on these towball incidents in a few of them it is the tow bar that actually failed but mainly due to corrosion.

Garry

Yep yep yep......it all comes down to maintenance.

A lot of the things we do in both towing and 4wding realy push the limits of what the vehicle is capable of.

If the vehicle and all its attachments are not in top repair, those limits are drasticly reduced.

AND attachent of items comes in for a lot of attention.

There are some quite spactacular videos that would be funny if the situation was no so dangerous.

cheers

Bantam, If you have a 1/2" pin, your set up is not standard! ! 16mm is the standard for Hitch pins! Michadel

Yes you are correct.

cheers