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Snatch Speed calculations

Posted: Mon Nov 04, 2013 1:22 pm
by Colinl
Thoughts wander at work...so
Snatching speed for a 8000kg snatch strap.

Trucks weight approx 2100kg.
Assuming the truck being recovered as a rigid fixing.

Using online calcs because qualified engineers are lazy a feck.
I want to put a max speed my truck can reach before I exceed the snatch straps capability. (8000kg)

http://calculator.tutorvista.com/physics/522/momentum-calculator.html

Momentum = Mass x vel (m/s)
8000kg = 2100 x vel (m/s)
=3.8 m/s Or 13.7 Km/h

Doesn't seem like much.

Obviously if the truck being recovered moves it'll have an effect on the delta Vel figure & that means you can recover at a higher speeds but I'd rather play i safe. (I'm also not taking into account the shock loading factor because of a snatch strap is being used but if you know what shock load factor to apply please elaborate!)

A rough guide to how hard you can safely recover at...

Re: Snatch Speed calculations

Posted: Mon Nov 04, 2013 1:37 pm
by mudlva
ah and don't forget that the "rated" recovery hooks are only rated to 10,000pds which is approx 4500kgs so effectively you should be going slow slow the vehicle that is stuck will be able to wait until summer when the mud will dry out and then they can just drive themselves out...
problem sorted :lol: :lol:

Re: Snatch Speed calculations

Posted: Mon Nov 04, 2013 1:42 pm
by Colinl
Ha ha my mind really wanders at work... Maybe a stick of gelli in the bog to clear it out then reassemble your truck when it all lands again. Recovered!

Re: Snatch Speed calculations

Posted: Mon Nov 04, 2013 3:06 pm
by suzolla
Hi,
Far too simplistic as depends on how stretchy the snatch strap is.
Also not sure why you are assuming the rating of the strap is equivalent to the momentum of the tow vehicle ?
Not saying I know how to calculate it without a bit of research, just questioning your assumptions.
Cheers
Tim