Kinetic Recovery Rope for Unimog??

[opie]

Sorry, I'm not really following what you are saying. You mentioned that both ropes would store the same mount of energy if the pulling force was the same. However, you then mention that the smaller rope would hold less potential energy as a function of rope length. What exactly does that mean and how would it translate to extracting a stuck vehicle? I knew I should have paid more attention in physics class!

Im no physics whiz either... But to answer your question simply...

Nylon stretches a certain percentage at a given load. For instance, the ropes I use stretch 6.7% at 30% of average tensile. In short, a 20' rope will stretch more in a linear sense than a 10' rope of equal diameter. Either should store the same amount of energy given the inputs are the same, but the longer rope will release that energy slower. The shorter rope will release the energy quicker and hence not hold that energy as long as the longer rope.

Make sense?

And Geo makes a good point. The recovery gear you carry in your vehicle should be sized for your vehicle. If you get stuck and someone shows up to extract you, then you should be using your gear.

 

[Jolly Roger]

And Geo makes a good point. The recovery gear you carry in your vehicle should be sized for your vehicle. If you get stuck and someone shows up to extract you, then you should be using your gear.

Which kind of brings me back to my original quandary about what size rope I should be getting. There seems to be a number of different thoughts on the subject. Some say I should be going for a rope that it rated at twice the weight of my vehicle. Others say at least 3-4 times the weight of my vehicle should be my target. Yet more people have said that with heavier vehicles like mine, I only need 1 - 1.5 times the weight of my vehicle. Soooooooo . . . should I be going for a 33,000 lb capacity which is just under twice the weight of my vehicle? Should I be going for the 52,000 lb option which is around 3 times my vehicle's weight?. Or should I go all out and get a 74,000 lb rope which is over 4 times my vehicles weight? Decisions! Decisions!

 

[opie]

Which kind of brings me back to my original quandary about what size rope I should be getting. There seems to be a number of different thoughts on the subject. Some say I should be going for a rope that it rated at twice the weight of my vehicle. Others say at least 3-4 times the weight of my vehicle should be my target. Yet more people have said that with heavier vehicles like mine, I only need 1 - 1.5 times the weight of my vehicle. Soooooooo . . . should I be going for a 33,000 lb capacity which is just under twice the weight of my vehicle? Should I be going for the 52,000 lb option which is around 3 times my vehicle's weight?. Or should I go all out and get a 74,000 lb rope which is over 4 times my vehicles weight? Decisions! Decisions!

The general consensus is 3-4 times your vehicle weight.

I think either rope would work. The quandary is if you go to big, you won't be able to get any stretch out of it. If the mass of the rig pulling you out isn't sufficient to load up the rope, then it's useless as a kinetic rope. I think you'd find the 1.25" rope a good fit. I think a 1.5" rope may be to big for real world use where other rigs on the trail may not go over 10,000 pounds. Unless you travel with like sized rigs, then get the 1.5" rope.