Kev M (NSW) posted:

Yeah,

I forgot that one,
also consider a compressor for reinflation.

Kev

Nick R (VIC) posted:

Tyre pressure is always the key, about 12lb in the 80 series when we went to fraser and it didn't look like stopping except one place on the east side where it is suggested that you don't drive!!! even then it just took some more herbs as there was no wheel slippage....

NickR

Member - Kiwi Kia posted:

Phil, Why do you say that shackles should not be rated over 3.25T ?
Other then the physical size (and weight) I don't understand why you should say this.

Member - Phil G (SA) posted:

Kiwi,
The most dangerous thing that can happen during a snatch recovery, is that a recovery point breaks, and you then have a flying missile attempting to kill the guy in the other vehicle. The bigger the shackle, the bigger that missile will be. Shackles never break during recovery (they don't break until about 30T when tested). So to put anything bigger is unnecessary and increases the level of danger.

Member - Phil G (SA) posted:

I guess to follow on,

Everything should be stronger than the strap. If anything were to break, then a broken strap is least likely to cause injury. So the chassis mounted recovery points need to be the strongest points - its very hard to get them rated these days. Many of us rely on the factory towing points, but if you can easily mount the 10,000lb hooks directly to the chassis with HT bolts, then thats the best option. Hooks are preferable to loops because they do not require shackles.

At the front, to increase safety, an equaliser strap (sling between two chassis mounted recovery points, and through the loop of the snatch strap) is best used - it halves the load on each recovery point, and should a recovery point break, the broken point and shackle will be retained by the opposite side. It also is kinder to the vehicle chassis.

At the rear, the square hitch towbar is most commonly used. Most people simple slip the hitch pin through the loop of the strap. They don't break. Some people say they bend, but only with a huge amount of force. The towbar manufacturers say "no way", but they are covering their butt. Towbars are attached to the chassis on both sides with a minimum of 4 HT bolts, so are a good recovery point.

Best to use no shackles at all. Then theres no extra potential "missiles". So Towbar to towbar is best, because it usually means no shackles, and the vehicles are mechanically stronger if pulling in a forward direction. Front to front is the worst, and to be avoided.

And if you minimise the required force by a bit of shovel work, then you're better off.

Most 4wd recovery is usually a mild tow or small snatch, but if you are in a situation where mud or wet sand are involved, you'll need to make it all as safe as possible.

Member - Kiwi Kia posted:

Hi again Phil, I agree with all your reasoning. I was just wondering why you emphasised that you did not recommend any shackle with a higher rating ("no higher, and no lower").

I will be involved with recording the actual forces during snatching of bogged vehicles next weekend, weather permitting, we don't want to get the data logging equipment wet :-)). It will be very interesting to see if the calculated forces actually do occur. We have tested recovery hooks to destruction on a static test rig with some interesting results regarding the failure of some factory fitted hooks but all the after market forged hooks reached their rated values before straightening. It should be noted though that some did not have any significant safety margin above the rated value. I will pm the dynamic results if you are interested.

D-Jack posted:

I don't think it would really matter if you got hit with a 3.25T shackle in the event of something letting go or 5T - either way I think you're in serious trouble!

Member - Phil G (SA) posted:

Kiwi,
Just weighed the two - 3.2T shackle is 650gm, while the 4.75T is 1050gm - so its 400gm heavier - I think thats a significant difference for no gain. They will both do a lot of damage, but a bigger shackle may get thru a cargo barrier, and a headrest, as well as the rear windscreen.......
"No lower", just because the shackle needs to be strong enough, but have to admit to having a sling and two 1 1/2T shackles for the Subarus I've had in teh past.

Great to hear that someone's doing some testing with the factory points. I remember some interesting info coming out of WA a few years back with the 80series loops - the loops were actually stronger than the 12mm HT bolts that held them on - most people assume it would be the other way. Also, our club did some demos of shackle damage some years back - loaded a snatch strap with a 3.2T shackle, and let it go - the shackle went straight through sheets of 20mm ply. We were actually looking at air brakes, and demonstrating how useless they were - found that a heavy item like a drag chain, draped over the strap was much more effective in slowing down a shackle.

Its interesting stuff - way too many myths out there

Cheers
Phil

Member - Kiwi Kia posted:

100% agree Phil, For years I have been trying to tell people that 'air brakes', parachutes or dampeners' were useless. However, I do believe that a brightly coloured item certainly should be used as it acts as a warning to others who may not see the strap / rope etc.

Member - bushfix posted:

g'day Phil,

re the drag chain, that is what I use, but not just to slow things down, it should also keep things lower to the ground rather than the potential of reaching above the waist. "risk management" i guess eh?

4be posted:

Thanks for the driver training bit. I had training around 8 years ago when I was with the RAAF. But I do think I need to brush up though.