understand where ur coming from, all about the circumstances
know I’ve got a recovery point on the back of my D3 but am very mindful that as the disco is getting older that maybe there’s rust behind it that I can’t see and therefore making it weaker , know the disco can tow 3500kg but must admit don’t know what the actual rating of that recovery point was when new
see one D3 member had a mishap with a strop breaking
Please show me where I have called you untrustworthy or a pillock.
I resent such remarks.
No I will not show you a picture of a modification. I would become the design authority if you copied it and something happened to you.
In my career yes I would have to supply full calculations of any design.
As I said, enjoy yourself and do what you feel comfortable with.
If you'd seen some of the so called "recovery points" my crew chief and I had to deal with.....its all about being sensible thoughif you're going to do a snatch.. dont use a skimpy rope and a 20 yard run. of course, recovery points were checked during scrutineering, werent they?
if someone's been stupid enough to get stupidly stuck, say, up to the windscreen in sticky mud... a snatch isn't the right tool for the job.
you should plan for ropes/chains/wires breaking because it happens
Put it this way, with some we used a special small shackle which would go through one, as it was so stupidly small and then connect to a proper size shackle. But this would ONLY be used for straight tow a few yards, deffo not a full on recovery.
If it was too dangerous we simply got under the car, if safe to do so, and attached either chains or soft shackles to a sensible point, usually part of the suspension, in order to not crush any brake lines, wiring etc.
And the MSR do not approve snatch recoveries, ever, which is why all recovery vehicles have to have both winch and jib.
I can only think what ann Robinson would have saidIf you'd seen some of the so called "recovery points" my crew chief and I had to deal with.....
Put it this way, with some we used a special small shackle which would go through one, as it was so stupidly small and then connect to a proper size shackle. But this would ONLY be used for straight tow a few yards, deffo not a full on recovery.
If it was too dangerous we simply got under the car, if safe to do so, and attached either chains or soft shackles to a sensible point, usually part of the suspension, in order to not crush any brake lines, wiring etc.
And the MSR do not approve snatch recoveries, ever, which is why all recovery vehicles have to have both winch and jib.
So can I ...... as i cannot see the connection, yet , oh yes, the Weakest Link!I can only think what ann Robinson would have said
(Thort you were on about her recent move to Countdown!
)and no i don't watch it either!
Traffic cops always use tow balls to tow. A good way to tell the difference between an area car and traffic (especially the beemer 5 series) is if they have the Swan neck towball.
Very interesting and to be honest never noticed , but indeed I assume they use the tow bar for ease of use when dragging a car across a motorway after an accident etc , thks again
The only way you will see a police vehicle around here is if it is a riot van
They do rounds here, I'm sure it's just 'hi vis' policingThe only way you will see a police vehicle around here is if it is a riot van
Hicap phill
Well-Known Member
Some competitions now do not allow jibs as they only pick up the front ends. Not good for 4wheel drive motorsIf you'd seen some of the so called "recovery points" my crew chief and I had to deal with.....
Put it this way, with some we used a special small shackle which would go through one, as it was so stupidly small and then connect to a proper size shackle. But this would ONLY be used for straight tow a few yards, deffo not a full on recovery.
If it was too dangerous we simply got under the car, if safe to do so, and attached either chains or soft shackles to a sensible point, usually part of the suspension, in order to not crush any brake lines, wiring etc.
And the MSR do not approve snatch recoveries, ever, which is why all recovery vehicles have to have both winch and jib.
drop flat trailer & rear winch made fast recovery work As for MSA scrutineers, I used to have the correct recovery shackle & if I could not put it through an eye I would make them fit a strap recovery point.
Oh the joys of MSA work
Thanks. As long as your kids are proud of you and you don't kill or injure anyone with negligence or stupidity you carry on.
Just read from page 1.
This comment has peaked my interest.
How many pulleys and what rating & anchors did you use?
I note you said “dragged “ not towed.
J
Yes and No.
The difference is that one of the vehicles is moving. That momentum is added into the equation.
In very 'simple' terms
Recovery 4x4 Weight: 2200kg
Recovered/Stuck 4x4: 2200kg (dead weight)
Recovery 4x4 speed: 22.34 mph before the load slowed it down.
momentum = mv, Energy = Work = 1/2mv2 ; Force = ma; Force = Work x Distance etc.
The speed must be converted to m/s: 22.34 mph = 10 m/s
Lets assume that the tow rope is 10 meters long and stretches 30%, so recovery vehicle stops in 30% x 10 = 3 meters.
So Force = Energy / Distance = 1/2mv2 x 1/d = [2200 x (10)2] / [2x3] = 36666.6 Newton = 36.66 kN = 3.74 tonne.
If the rope doesn't stretch it would be 7.48 tonne shared equally and (as you said) the shock would be greater.
Shock isn't the right word really ( ask von Neumann about his conjectures) but I know what you mean.
The transfer of force resulting in the decelleration of the moving object is transfered as accelleration to the stationary object. It is horribly complex and can't easily be calculated and is often underesitmated which is why there are so mnay 'accidents' using this method.
My advice would be 'don't' .... use a winch or a rope and some pulleys... if you see someone using a snatch recovery, stand well back.
Hicap phill
Well-Known Member
Here we go for the safety people. While at a job today spotted the insurance man checking out the winch. He unwound all the dynema rope.
I did say to someone...hope they have secured the end as he wanders of with the hook.
I did say to someone...hope they have secured the end as he wanders of with the hook.
hi
many thks , think I know what u mean, alas most of it went over my head but indeed understand why usinf a winch etc is better, so it’s a slow constant force and not a quick shock loading onto the vehicle points
must admit have never used a kinetic rope due to the dangers, always taken up slack very slowly and applied a steady pull not floored it as don’t fancy having something go through the back of my landy
In the last odd 30 x years of greenlaning that I’ve done indeed seen some really dangerous things , even someone stepping over a wire winch rope , front dumb irons and rear cross members ripped off an old series landies
don’t think some understand how much stress is on a vehicle when off roading , of course depends on the course , know I snapped my chassis on my old 88, chassis was rotten and it just finished it off, lol
thks again
Ur right , ages ago I helped someone pull his winch rope out , suddenly went slack , yep , it came off the spool , lol
As a side note , managed to pick up an absolute bargain off ebay , a front nudge bar that I still need to fit , also see there going up in price, some asking £4-500, only thing that will be fun is drilling the holes in the right place on the front bumper, lol
plus me waffling also got a boot sliding floor, my god there also going for silly money , have nearly finished restoring some rock sliders , should come in handy at the supermarket’s car park as some idiot bounces there door off them, snigger
I better stop talking shouldn’t I before I keep waffling on, lol
Just read from page 1.
This comment has peaked my interest.
How many pulleys and what rating & anchors did you use?
I note you said “dragged “ not towed.
J
Yes. A friend needed to move a 40' high cube container across a concrete slab by 10' so he could get another one in.
The container wieghs 4000kgs and was sat on some steel spreader plates.
It was full of wood at the time which I was told weighed 20 tonne but I think that was exaggerated.
We has a load more spreader plates to play with and some 1200x900x10mm Hardox sheets.
I have a Goldfish winch rated to 11500lb (5216kg) with 11mm Dyneema rope (5896kg).
I use 5/8" rated 3.25T, green pin shackles and 3 ton (WWL) lifting slings and straps.along with a couple of 10ton recovery straps which I use to connect to anchors/wrap around trees.
I have several diffent snatck blocks, mainly 'stamped' 8 ton and also use pulley wheels that fit the pin of a 3.25T rated shackle.
There are loads of videos and stuff on UTube and lots on the mechanical advantage gained from using pulleys.
I try to calculate a 3 ton load on the winch. The D90 with the brakes locked on and a couple of bricks in front of all 4 wheels normally suffices as the 'limit', ie if it rides over the briks i'm around 3 ton.
From the winch to 1 corner, through a pully to another container, back to the center leg, through another pulley back to another pulley attached to the back corner, through a pulley to a tree (which I moved to a forklift as it started to bend).
I use 2 ton lifting slings to attach the pulleys
6 lines each taking 3 ton
We needed to encourage the container to move the first few mm and put some oil on the speader plates to quiet the squeal plus stick some wedges under one of the anchor containers to stop it moving, but we got there.
Heres a pick of the low-load pulley blocks.
I also use these ... https://goodwinch.com/product/swingaway-pulley-block-3/ which I much prefer to the std 'Orange/Red' Rhino Winch types with the small axle...
Most pulls I do use at least 1 pulley/block, often two - winch, load, anchor back to load.
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I like waffles.. especially with maple syrup
