Some thoughts on Snatch Straps, winch and other items of recovery..

[outback]

Updating the recovery gear and thoughts.

After adding a few extra things to the patrol and looking at want was on it before the new additions I suspect the girl has had a bit of a base weight gain.
I decided its time to reappraise such things as snatch blocks, snatch straps, tree trunk protector etc.

Whether I need to update is a different issue but it pays to keep an eye on loads and what is needed.

I did a bit of web surfing and came up with some basic points that were reoccurring:

1. Minimum breaking strength of the strap should be between 2 and 3 times the vehicle’s gross vehicle mass (GVM).

2. The strap must be suited to the GVM of the lighter of the two vehicles used in the recovery process

3. A strap with a ‘too light’ breaking strength may break under load. A strap with ‘too heavy’ a breaking strength may not stretch properly and more stress will be placed on the recovery points, possibly causing damage or injury.



Now Nissan suggests, stares, the GVM should be about 3060 kg, simple terms 3t.

So you have:
You
The Minister of Finance and War,
Any associated 2 legged encumbrances,
Nissan bull bar*,
Tow bar*,
Rock sliders,
Under body bash plates*,
Diff armour*,
Winch*,
Dual battery system*,
On board air compressor and tank,
2 full tanks of diesel, 90+l and 30+l.
Roof rack,
Second spare wheel,
Recovery gear,
First aid*,
Fire extinguisher*,
Cargo Barrier*,
Draw system,
Fridge,
Side awning,
Sleeping gear,
Cooking gear,
Gas bottle; assume 4kg,
Food for about a week,
Water for week,
Tools,
Spares, (?), depends on trip,
Anything I missed.

This assumes you don’t have a camper in tow as well. That may reduce the vehicle load though.

So you are still under 3t for the Patrol?


First back to the snatch strap.
Theory its to be 2 – 3 times GMV. Or should this be 2 – 3 times the complete vehicle mass.

Now on standard GMV, a snatch strap should sit in the 6000 – 9000 kg breaking strain.

But with above load is a 8000 kg snatch strap going to work or just get over stretched/break?

So in reality should you consider a 9000kg snatch strap more that the 8000kg one?

Add a camper trailer to the vehicle then the problem goes more to the 9000 – 10000 kg strap.



Winch issues:
If you run with a standard Nissan bull bar it is recommended for the Warn 9000 lb winch.
So if you stick a 12000 lb winch on it, is this not being over loaded if you start getting above the 9000 lb of winch load?

But how many will think," hey I have a 12000 lb winch so I only need a 1:1 line pull here", when they should still be doing a 1:2 or 1:3 pull because of the bull bar and mount ratings.

Ok so far a bit of rambling but it’s the start of what is really needed.
Vehicle off soon for a base load weigh in. Hope she does not see the weight.

Base load: These are things that don’t leave the vehicle. Yes the fuel will change but I start off with full tanks.
This is what is always in the vehicle even if I am just highway cursing between home and Adelaide.

Nissan bull bar*,
Tow bar*
Under body bash plates*,
Diff armour*,
Winch*,
Dual battery system*,
2 full tanks of diesel, 90+l and 30+l.
Recovery gear*,
First aid*,
Fire extinguisher*,
Cargo Barrier*,
Some tools*.


Just thinking out loud ...

[the evil twin]

Some very valid points raised so here is some of the info that I pass on to students on courses I am involved with.

Be very aware of just how heavy a mired vehicle may be.
The WA SES use many vehicles, predominantly the 70 series troop carriers and Patrol and Cruiser Wagons.
The troopies are an 11 seater however we are limited by SOP's to 5 to 6 depending on vehicle config because we have long range tanks, steel bars, winches, extra batteries, steel roof racks, radio equipment etc. which gets the vehicle to the GVM with all that gear and only 1/2 the seating used.

Snatch strap rating - 8000 or 9000 makes little difference as the ratings are not to a Standard and actual performance can vary hugely hence the "2 to 3 times" variable.
If you have to exert 9000 Kilos of force to a mired vehicle to get it out you are in very, very dangerous territory and have not done sufficient shovel work, vehicle preparation or track improvements to debog the vehicle.
I might add that snatching should be the last method of recovery employed to move a vehicle.

Snatch recovery with a trailer attached is bordering on suicidal.
IMHO you would have to be loony tunes to attempt it.

Winch ratings - because winches are mostly rated in pounds a 12000 is close enough to 5000 Kg in my book
Will a good quality bar steel bar mounted correctly handle that considering it is a static and not a shock load?
Remembering that you can only get anywhere near that rating on the first layer and with top notch cabling I would like to think so.
Esp considering the mounting can be pretty much identical to how rated recovery points are attached
When rigging to advantage, say a 2 to 1 I also insist that the anchor is not back to the winch mount but to a seperately rated point or part of the vehicle so the load is halved?

[outback]

Thanks ET. You are just confirming my own opinion here.

[outback]

The ramblings I have posted are draw on what I have read on several forums.


I suppose the big questions are:
1. Are we, in general terms, over weight when heading out on that trip?
2. If so is the recovery gear carried up to that load?

All the added hardware: e.g.:

Bull bar,
Tow bar,
Rock sliders,
Under body bash plates,
Diff armour,
Winch,
Dual battery system,
Roof rack,
Cargo Barrier;
adds up and reduces the available load capability of the vehicle.



Comments re snatch straps and winches are more to see/hear people's thoughts on this whole issue.


Towing a tent trailer/campervan/caravan will change/reduce possibly real on board vehicle load but tow ball weight now also comes into the vehicle's GVM.