Equilizer strap

[Two89w Member Find all posts View Profile Close Two89w]

I have a 8T snatch strap, 3.25T bow shackles for the front recovery points also rated at 3tonne each.

What length and tonne rating equilizer strap should I be buying?

[2016VX Junior Member Find all posts View Profile Close 2016VX]

I'd be getting an equaliser strap that is rated the same, if not higher than your snatch strap. So 8T or more. 2.5-3.0m should be sufficient length for an equalisation strap.

[Mr ok Lurker Find all posts View Profile Close Mr ok]

To answer your question. To match the 8t strap you will need at least 3m and 8t breaking strain/4t working load. The week point will be where the equalizer strap joins to the snatch strap.

For a perfectly straight snatch where the two legs are equal length, a 3m strap will give you a 30 degree angle at the apex which will result in 4.15t (40.6kN) of load on each leg if 8T (78.5kN) was applied to the snatch strap. Basically, the equalizer strap will halve the load on each attachment point. The lower ratings for the shackle and anchor point would be based on yield strength, most likely with a safety factor included.

To apply an 8T load to the strap, my calculations come to a 3T snatching car decelerating from 38kph in 0.4 seconds (2.1 meters of stretch). As a comparison, a 3T car decelerating from 18kph in 0.5 seconds (1.3 meters of stretch) will give you 3T of load on the strap.

[2016VX Junior Member Find all posts View Profile Close 2016VX]

Mr OK. I saw your post and immediately thought to myself "4.15t on each leg does not sound right!". Then I got out my pen, paper and calculator, and a few SINs and COSs later I found that you are almost bang on.

I went to the additional step of measuring the distance between recovery points. It is 0.9m. This makes it 34deg at the apex if using a 3m equalising strap. Assuming an 8T snatch strap load at 90deg to the stranded vehicle, it results in a 4.18T load on each leg of the equalisation strap.

Good work!