If you had doubts about pull ropes...

[Rustyiron]

If it's just a rope, you have a chance of survival. But what about that 3lb steel clevis that he connects them with?

I've never used a clevis, just drop the loop over the ball and a tow hook. The failures I've seen are somewhere in the middle. Maybe I've been lucky, a flying clevis would definitely "leave a mark"

 

[ovrszd]

I've never used a clevis, just drop the loop over the ball and a tow hook. The failures I've seen are somewhere in the middle. Maybe I've been lucky, a flying clevis would definitely "leave a mark"

I've never tried the ball trick. We always use screw in shackles.

I've saw two rear bumpers yanked off trucks by hooking to the bumper.

Someone on here much smarter than me can do the math concerning how much energy is applied when you take a ten foot run on 40ft of stretch rope. It's many times more energy than can be applied on a tight chain pull.

I wouldn't even know how to mathematically compute that.

 

[Rustyiron]

Richard you speak of a rope, are you referring to the "new" (as far as I know) purposely made snatch type. I've only been aware of these for maybe 5 years or so. But then I don't get out much either.

 

[CobyRupert]

I've never tried the ball trick. We always use screw in shackles.

I've saw two rear bumpers yanked off trucks by hooking to the bumper.

Someone on here much smarter than me can do the math concerning how much energy is applied when you take a ten foot run on 40ft of stretch rope. It's many times more energy than can be applied on a tight chain pull.

I wouldn't even know how to mathematically compute that.

It’s easier to calculate the force than the energy.
One way would be to measure the acceleration (a) of the pulled vehicle, and knowing it’s mass (m), the force (F) applied was F= m x a. This assumes pulling vehicle came to a stop at maximum stretch. Trying to figure how much moving pull vehicle contributes on top of rope’s stored energy makes calculation more complicated.
Another way would be to consider the rope like a spring, and find its spring constant (k). This is a measure of how resistant it is to being stretched. And measure how much it got stretched during the pull. Assuming (k) is the same whether it’s stretched 1 foot or 8 feet, the force (F) required to stretch it “X” feet is: F= k times X. That’s the force it has at a particular stretched distance. The energy (E) over the length of the spring as it snaps back (various distances), involves integration (complicated math), but boils down to E=1/2 kX^2 .
Again, it’s easy to calculate stored energy contribution, but not moving energy contribution of the pull vehicle.
However, if we know how much the pulled vehicle accelerates beyond what the “spring” can contribute, the pulling vehicle must of contributed this.
.....of course, this assumes pulled vehicle was in neutral and contributed none.

In conclusion: Just floor it and let ‘er rip.

 

[Redlands Okie]

If it stretches it can hurt you on the snap back. That’s why there is a difference between slings and snatch ropes. Even chains will stretch then break. It’s just hard to tell unless you look closely at the links.

 

[Rustyiron]

I've never tried the ball trick. We always use screw in shackles.

I've saw two rear bumpers yanked off trucks by hooking to the bumper.

Well this was waay back, high school and after when we were kids, knew everything and also bulletproof.

 

[SylvainG]

I've never used a clevis, just drop the loop over the ball and a tow hook. The failures I've seen are somewhere in the middle. Maybe I've been lucky, a flying clevis would definitely "leave a mark"

You mean the ball of a hitch? If so, what I've read is this is not recommended. As you pull, the back will lower and the strap can break free of the ball.

 

[Farmer495]

I've never used a clevis, just drop the loop over the ball and a tow hook. The failures I've seen are somewhere in the middle. Maybe I've been lucky, a flying clevis would definitely "leave a mark"

Read an article about a clevis on end of tow strap coming off a hook (not captive) and breaking truck windshield and penetrating skull of truck driver. :-(

I've also worried about the ball some how breaking and becoming a 2 5/16" cannon ball.

I have a hitch slug with a screw in clevis for towing.

 

[ovrszd]

Richard you speak of a rope, are you referring to the "new" (as far as I know) purposely made snatch type. I've only been aware of these for maybe 5 years or so. But then I don't get out much either.

I first knew of stretch ropes in 1977. Not sure when they were first sold. They've been around a long time. The forces they allow the user to exert are extreme. That's evidenced in the videos posted. That force is extremely dangerous and should never be under estimated.

And I don't get out much either. But I somehow have history with these ropes.

 

[ovrszd]

It’s easier to calculate the force than the energy.
One way would be to measure the acceleration (a) of the pulled vehicle, and knowing it’s mass (m), the force (F) applied was F= m x a. This assumes pulling vehicle came to a stop at maximum stretch. Trying to figure how much moving pull vehicle contributes on top of rope’s stored energy makes calculation more complicated.
Another way would be to consider the rope like a spring, and find its spring constant (k). This is a measure of how resistant it is to being stretched. And measure how much it got stretched during the pull. Assuming (k) is the same whether it’s stretched 1 foot or 8 feet, the force (F) required to stretch it “X” feet is: F= k times X. That’s the force it has at a particular stretched distance. The energy (E) over the length of the spring as it snaps back (various distances), involves integration (complicated math), but boils down to E=1/2 kX^2 .
Again, it’s easy to calculate stored energy contribution, but not moving energy contribution of the pull vehicle.
However, if we know how much the pulled vehicle accelerates beyond what the “spring” can contribute, the pulling vehicle must of contributed this.
.....of course, this assumes pulled vehicle was in neutral and contributed none.

In conclusion: Just floor it and let ‘er rip.

And lay down.