Scary stuff

[playdoh]

Don't know if anyone here has seen this before, I came across it on another forum, it's a new 'recovery device' listed in the trading post.

http://www.autotrader.com.au/photodispl ... 7487522341

Understandably, it caused a pretty strong reaction from it's previous posting, and no, this isn't a joke, unfortunately.

[dansedgli]

Are you sure you didnt come across that thread on this forum?

Its in the discussion area.

[playdoh]

No it was on 4wd Monthly forum, didn't see it in the discussion area.

PS. still can't.

[gu4800]

No it was on 4wd Monthly forum, didn't see it in the discussion area.

PS. still can't.

http://www.outerlimits4x4.com/PHP_Modul ... t=receiver

[playdoh]

So it is, thanx.

On the upside, i've figured out the search function now, and it might get seen by those who missed the other post.

[dinos4x4]

Who evers idea that is they are asking to get sued

[HotFourOk]

Some people have little to do...

Who cares if you have to take your tow ball off to put a shackle in... You're bloody stuck anyways.. an extra minute wont hurt you

Lots of people just don't see the safety risks in a recovery... Its just one of those things you need to see with you're own eyes before you realise how much force is actually used.

[Shadow]

it looks asif the shackle cant be removed from the ball unless the pin is removed from the shackle, looks like it tapers off, which if it cant be removed, i dont really see a problem with it.

Unless youyr saying that the ball cant take the load? it says a 50mm ball can take a 12.8tonne load, which most snatch straps arent rated to?

[GRINCH]

why not just put the strap straight over the tow ball

[HotFourOk]

it says a 50mm ball can take a 12.8tonne load

Yeh.... it 'says'

[HotFourOk]

why not just put the strap straight over the tow ball

Spose there's a chance of it coming off when the car jerks..

Just dont use a bloody towball at all!!

[Shadow]

it says a 50mm ball can take a 12.8tonne load

Yeh.... it 'says'

well there are different rated 50mm towballs, 1800 2500 3500 (thinkj 3500 is the best)

so i guess if you have a 3500kg 50mm towball youd be pretty right

would be scary if you had something like a 900kg towball of a toyota starlet or something, but then that ball should always be an indication of the weight of the vehicle its fitted to, since the towing capcity is based off this.

[pongo]

so i guess ................

..............should always be an indication of the weight of the vehicle its fitted to, .

Assumption is the mother of all fark ups

[HotFourOk]

I'm not sure how the towballs are rated though... Recovery's involve lots of shear force on the towball (horizontal).. towing applications also deal with the weight pushing down on the towball (vertical), which is not evident in recovery operations.
So it depends on the methods in which the items are tested to give this rating.

It takes less than a minute to remove one... so I'll be a minute longer... but hopefully be safer in the long run.

How many clubs out there allow snatching from a towball??

[Shadow]

I'm not sure how the towballs are rated though... Recovery's involve lots of shear force on the towball (horizontal).. towing applications also deal with the weight pushing down on the towball (vertical), which is not evident in recovery operations.
So it depends on the methods in which the items are tested to give this rating.

It takes less than a minute to remove one... so I'll be a minute longer... but hopefully be safer in the long run.

How many clubs out there allow snatching from a towball??

i would just use the pin anyway, as this is far easier and in my opinion safer, but as someone on explore-aus said, most bow shackles are rated at 3.2tonnes, which is less than what a 3.5tonne tow ball is rated at.

[Jimbo]

Rated shackles usually have a saftey factor of around 10.
Tow balls are under a lot of bending stress and not sure how they are rated.

Bond

[RAY185]

so i guess ................

..............should always be an indication of the weight of the vehicle its fitted to, .

Assumption is the mother of all fark ups

Its been way too long since I saw that movie.

[Bunyip]

Ok here goe's!!!!
I run my own small driver training buisness which include's recovery and ofcorse SAFE!!!!!!!!practices
in the 4wd world the is no requirement or law's when it come's to the use of rated stuff e.g. strap's shackels recovery points it is at the owners descretion. But because the rated stuff that we 4wders use actually comes from the craning industry, rigging and dogging where you actually need training and tickets to use the same equiptment, GO FIGURE?? the problem is that tow balls are rated in the automotive industry for towing. NOT SNATCHING!!!!!! THEY ARE NOT RATED FOR SUDDEN IMPACT OR SUDDEN FORCE. I have seen a few times the tow ball snap of at the neck becoming a leathal missile I also have seen the bolt on type tow hitch snap. the best recovery point if you have to use a tow bar is the square hitch and pin type remove the tow hitch insert your strap into square hole replace the pin through you strap
MY ADVICE IF YOU SEE ANYONE USING THAT PRODUCT DONT STAND IN THE LINE OF FIRE!!!!!!!!!!!!!!!!!!!!!!!!!

[frp88]

we use lifting gear at work and that looks more like 4.75t there is no way any car is going to come close to loading it up anywhere to it breaking point.are you guys forget that it is a natch not a chain which is direct shockloading.iam going to find out what the shear rating off tow ball is it must be 20mm in dia and that would take alot of force.anyway the recovery point on a new 4bee would not of that dia.i only see 1 problem in that the shackle could come of and then it would it would become the problem.

[Jimbo]

Under straight shear the towball is very strong but its under bending as well shich greatly reduces its strength

[Shadow]

Under straight shear the towball is very strong but its under bending as well shich greatly reduces its strength

recovery hooks are under the same stress and i dont know anyone thats bent a recovery hook.

[Jimbo]

"recovery hooks are under the same stress and i dont know anyone thats bent a recovery hook."

Totally different.


The best thing about a recovery hook is that it bends rather than fails so you get the strap coming back WITHOUT a peice of metal attached.

[HotFourOk]

Under straight shear the towball is very strong but its under bending as well shich greatly reduces its strength

recovery hooks are under the same stress and i dont know anyone thats bent a recovery hook.

Didnt you just read that towballs are not made for sudden forces.. whereas recovery points/gear is designed to cope with these forces.

JUST DON'T USE IT! It is really so simple.

If you do use your towball.... dont expect any sane person to snatch you out

[Shadow]

Under straight shear the towball is very strong but its under bending as well shich greatly reduces its strength

recovery hooks are under the same stress and i dont know anyone thats bent a recovery hook.

Didnt you just read that towballs are not made for sudden forces.. whereas recovery points/gear is designed to cope with these forces.

JUST DON'T USE IT! It is really so simple.

If you do use your towball.... dont expect any sane person to snatch you out

youve heard of brakes right?

what happens when your going 100 and you put your foot on the brake. The trailer (1tonne) exerts sudden force on the tow ball.

now sure a 3.5tonne trailer is supposed to have brakes, but if those brakes arent as good as the car's brakes alot of the 3.5toinne is going to be applied to the 50mm ball.

The difference between a 50mm tow ball and a recovery hook is that a 50mm towball IS designed to have these forces applied to it every day. A recovery hook is a piece of emergency equipment and normally not used every day, and as such probably not designed to the same tolerences.

Also, a snatch strap doesnt put shockloading on the recovery point, thats why we use a snatch strap, it doesnt shock load the vehicle.

A snatch strap can exert up to 8000 pound of force, (3.6tonne?) or 10000lb (4.5tonne) depending on what strap you have, but it certainly isnt shock loading, its more of a sheer force than a towball is designed to live with.

[HotFourOk]

EDIT -

A trailer makes more sense... but the forces are nowhere near a snatch
recovery

[Shadow]

Didnt you just read that towballs are not made for sudden forces.. whereas recovery points/gear is designed to cope with these forces.

JUST DON'T USE IT! It is really so simple.

If you do use your towball.... dont expect any sane person to snatch you out

you said they arent made for sudden forces

yet they are... thats exactly what they are designed for.... its called braking...

[Shadow]

EDIT -

I just read the last post again... I can't say anything... It has no relevance whatsoever.


Oh yeh, you know when you are doing a snatch recovery, you slam your brakes on it creates sudden force just the same.

That is how much relevance your post had.

um, i was talking about towing a trailer at 100kkm/h and hitting the brakes

should have made that more clear...

[HotFourOk]

As if a trailer braking from 100km/h is ANYWHERE NEAR a force used in a snatch recovery...

And Sudden does not refer to the speed of a car braking.... that is very very slow

Sudden is going from no force to a force of a number of tonnes in a second or so.
Not a gradual force like braking.

The trailer has the same momentum as the vehicle towing it when driving along at first, so any change in momentum is not going to produce a great deal of force on the towball. And heavy trailers require brakes anyway. So its still of no relevance.

You obviously have no idea about recovery techniques. End of story.

kthnxbye

[Shadow]

As if a trailer braking from 100km/h is ANYWHERE NEAR a force used in a snatch recovery...

F = M x A

Braking distances are calculated using a friction coefficient of 0.8xG. this is based on new (very good) tyres on a dry road.

So the braking force is 0.8 x 9.8m/ss = 7.84m/ss

F = M x A

= 1000KG x 7.84m/ss
= 7840KGM/ss

so a 1tonne trailer behind a car doing 100Km/h exerts 7.84tonnes of force on the tow ball. Remember, this is the actual force and can actually happen.

Even assuming a braking coefficient of 0.5xG (mud tyres prolly) the force is 4.9tonnes.

And this is on a 50mm ball rated at 1tonne. So what can a 3.5tonne ball handle? As you say a 3.5tonne trailer is required to have brakes so the same maths cannot be used. But assuming the brakes on the trailer failed, that 3.5tonne trailer would be pushing the car infront with a force of 27.4tonnes.


7.84tonnes is 57% more than a 10,000LB snatch strap is certified to handle.

[DR Frankenstine]

As if a trailer braking from 100km/h is ANYWHERE NEAR a force used in a snatch recovery...

F = M x A

Braking distances are calculated using a friction coefficient of 0.8xG. this is based on new (very good) tyres on a dry road.

So the braking force is 0.8 x 9.8m/ss = 7.84m/ss

F = M x A

= 1000KG x 7.84m/ss
= 7840KGM/ss

so a 1tonne trailer behind a car doing 100Km/h exerts 7.84tonnes of force on the tow ball. Remember, this is the actual force and can actually happen.

Even assuming a braking coefficient of 0.5xG (mud tyres prolly) the force is 4.9tonnes.

And this is on a 50mm ball rated at 1tonne. So what can a 3.5tonne ball handle? As you say a 3.5tonne trailer is required to have brakes so the same maths cannot be used. But assuming the brakes on the trailer failed, that 3.5tonne trailer would be pushing the car infront with a force of 27.4tonnes.


7.84tonnes is 57% more than a 10,000LB snatch strap is certified to handle.

YAY SOMEONE WITH A BRAIN. Ok boys look at the little pin holding your hook on your 9000lb winch. (don't bother saying they don't get shock loaded occasionally). Now look at your towball. 10mm vs 22mm which is stronger?
You will never break a 3500kg towball with a snatch strap GET OVER IT!!
Towballs were breaking when people used the two piece ones.
4WD monthly did a sort of Myth Busters a little while ago and stated that though they didn't reccomend its use(litigation and all that) a 3500kg rated towball was quite safe to snatch off.