Bubba rope

[FritzTKatt]

I wouldn't try to extract much more than a heavy atv with a 10k.

A little wisdom... we got the Army's field recovery manual for our AAVR7 class, despite that it doesn't list anything about the AAV, and has a big warning on the first page that says "THIS DOES NOT APPLY TO THE MARINE CORPS"... but it was testable anyway... haha. As I was, a vehicle mired to the axles getting hung, only requires the vehicles weight of force to recover it. A 40% reduction of force can be accounted for if the vehicle is capable of moving under it's own power (applies to all situations). Vehicles up to hull depth (tires completely buried) requires 2x the force of vehicle weight. And one stuck up to the turret can be 3x or more (ranger is buried up to the top of the wheel wells).

Now that I think about it, as I get further off topic but am still going, I'll see if I can get a digital copy of that manual so the mods can sticky it or make it into a tech article.

 

[swynx]

Ya I've broken many 10k thought I was going to break a 17 but haven't tugged allot with it. That's why I want 30k-40k.

I figured there was some kind of math to say how much suction the mud had.

 

[FritzTKatt]

I'll see what I can do on monday. Even though it was written by the army, the manual does have some good stuff in it. Not all of which is pertinent to RBV recovery, but a good read for anyone going off-road.

It's not specified, but we all know that thicker mud has more suction to it so you can expect a harder pull...

One thing I have to account for now that wasn't a problem just recovering a ranger, is that snatch blocks are considered a 10% resistance to the overall force. When you have to pull a 26t track mired to the hull, you need a lot of blocks.

 

[swynx]

We use snatch blocks more to pull at and angle than we do for multiplying power

 

[4.0B2]

I'm still voting on a winch

 

[Andy D]

The strap stretched almost 4 feet then contracted . It would prolly tow just fine too I'm glad the pick up held on because that strap had a lot of energy. It isn't just a straight pull. like a cable or a chain. They are no fun when they break either. I worked around 150 ton cranes in the ship yard. The basic safety factor was 3 times the rated max. Stuff still broke, In the 11 yrs I worked there , 2 guys were killed when they pulled a crane over. One was a dummy , the other was a victim of bad engineering. Be careful out there. Trust me, you dont want to be around a lifting or pulling gear failure. AKMHIK

 

[swynx]

Yeah I vote winch.

I'm waiting for a bumper to come off because of the energy

 

[FritzTKatt]

Definitely have a winch, but you'd have to be high to think I leave the pavement without a strap (or 3).

That's why you need loops/shackle points, or at least hooks. Or build a ridiculous bumper and hold it on with 3/4" bolts... that has lift lugs on it anyway.

 

[FritzTKatt]

As promised, I found a .pdf of that BDAR manual. Great read for any off-roader, not too much truly applies to civilian vehicles, but the principles remain the same.

http://armypubs.army.mil/doctrine/DR_pubs/dr_a/pdf/fm4_30x31.pdf

 

[ridgerunner]

One time I used a picnic table to extricate a Japanese guy in a Focus from a beach on Presque Isle peninsula. He got himself dug into the bumper in the front.

Hmmm...Japanese guy stuck in Focus rescued by picnic table ...yes, yes U now have my attention please continue.