Weakest point in winch and rigging?

[ntsqd]

In looking at the linked page I see that the 10.000kg rope shackle is labeled as being "16mm". I would assume that most folks use 5/16"<->8mm rope on their winches (or maybe 3/8" - 10mm on the bigger winches), so the 16mm shackle would probably be enough larger as to avoid the tight radius bend within the shackle itself that kills this type of rope. Then so long as the the winch rope is properly eyeleted there should not be any problem.

I very much like the idea of these shackles, but I'm going to have to make some mental adjustments if I ever use any.

 

[Capt Eddie]

I have found the weakest link. The 3/8 inch clevis pin the is used to attach the hook to the cable. 3/8 x 1/2 inch piece of metal stands betwwen success and failure. We use four 1/2 inch bolts minimun to hold the bumper to the truck. Four 5/16 bolts hold the winch to the bumper. Our snatch block has 1 inch bolt thru the sheave. It all comes down to one little 3/8 clevis pin. But I have never seen or heard of the pin breaking. Why is this??

 

[ntsqd]

Because it is loaded purely in double shear and was sized for the job.

The bolts have to deal with complex combination's of tensile, single shear, and bending loadings; and have a lot tougher job to do.

 

[Bongo Boy]

There was an article several years ago in a Jeep mag, and they had a tensionometer and did a bunch of scenerio type pulls. They were not as high as you might think.

Thanks--having at least some anecdotal data is very nice, even if there's a large range. Yes, I'm a little surprised by the numbers--I simply had no idea what they might be.

It's a great idea to have some idea of the weakest point in a complete recovery situation, not just in the frame-to-hook components on the recovery vehicle. I imagine a fine setup can be beside-the-point in cases where a bad hookup is made when recovering, either through carelessness or simply not knowing how the target vehicle is assembled.

 

[johnnyrover]

Weakest link = operator!

In my experience, rope is safer but subject to more environmental damage (including sand and ice); cable is more durable but dangerous when it lets go.

Failure points seem to be outside the winch/cable/block and more with the connection points (weak bumper, poor selection of recovery point, etc)

I have had both rope and cable fail, and finally settled on a hybrid solution.

We used a shorter cable on the winch with a rope extension (kept in the truck). This kept the rope away from the environment (sand, ice, sun) and reduced our exposure to cable under load.