Holdfast Advice Needed - Ground Anchors

WonDERR

Clanker
Can anyone help this foxhound with some holdfast advice please?

I've just been given a ground anchor plate and pins - the type that's about 18 inches long with 5 pins of about the same length (as opposed to the pattern that is about a yard long with 8 long pins with eyes). I assume it's RE kit, it's certainly British issue.

Will that ground anchor have sufficient holding power (in 'average ground'!) to act as an anchor for a tirfor winch (1600 kg type) recovering a 110 defender?

Thanks in advance.
 

Arte_et_Marte

ADC
Moderator
Couple of points from an ex Recy Mech Sergeant.

I haven't seen the type of ground anchor plate (GAP) to which you refer. We (the professionals) used the longer 8 hole plates and longer pins to which you also refer.

There is no such thing as 'average ground.'

It would appear that the smaller GAP and pins are about 1/2 the size of the standard recovery issue GAP.

Given that the larger GAP can withstand a 4T pull (that's 1/2 a ton per pin) in solid ground I would hazard a guess that the smaller GAP will be about 1/2 of that and with only 5 pins will work out at 1.25T per plate.

The bigger GAP's can be placed together with a maximum of 4 in a line (16T) or 6 in an arrow formation giving 24T. The angles (and straightness of the 4 in line arrangement) are critical.

Some more factors need to be considered if you wish to successfully recover your vehicle, regardless of the type of winch involved.

An estimated pull (EP) in tons needs calculating.

For this you need to know five things.

1) Type of soil. (The state of the ground or Ground Factor is known as rolling resistance.) (RR)

2) Any wheel/track damage to the vehicle to be recovered. Damage resistance. (DR)

3) Any gradient that the vehicle needs to be winched up. (GR)

4) Weight of the vehicle to be recovered. (WOV)

5) Any change of direction involving a non direct pull.

A safety factor of 25% is then added to the total tonnage to maximise a first time recovery. (SF)

Therefore RR + DR + GR +SF = EP (Estimated Pull)

1) Type of soil: Obviously pulling/winching a vehicle on hard standing is a lot easier than pulling it though clay/deep mud, therefore a basic knowledge of soil mechanics gives a weight percentage for any particular type of ground condition.

i.e. On hard standing GF is 1/25th WOV. In deep mud/clay it is 1/2 WOV with various percentages and ground type in between those. Gravel is 1/5th WOV grass is 1/7th WOV.

So: WOV divided by GF = RR

2) Wheel damage is straightforward. One damaged/locked wheel is 1/3rd WOV and two damaged/locked wheels is 2/3rds WOV.

So: WOV divided by 1/3rd (or 2/3rds) = DR

3) Gradient is also easy. Known as degree of slope (DOS) any slope up to 45 degrees is proportionate 1/60th WOV and anything steeper than 45 degrees is the whole WOV.

So: For 15 degree DOS. WOV x 15 divided by 60 = GR

4) Is simply the weight of the vehicle to be recovered.

5) Don't worry about change of direction at this stage.

So: Let’s say your 110 Defender weighs 3T it is stuck in deep mud with no damage and there is no gradient. (I am rounding up the numbers below)

RR. WOV / GF = 3/2 = 1.5T

DR. = 0T

GR. =0T

SF. 25% of 1.5T

EP. Estimated Pull = 1.9T

Now, you have a 1.6 ton Tirfor winch.

Given the EP this winch will not be adequate enough to recover your vehicle with a single line pull.

As I stated at the start of this post I am only guessing at the WLL (working load limit) of the GAP’s that you want to use, this being 1.25T per plate. One plate therefore will not suffice either.

What you are looking at in this scenario then is the use of 2 GAP’s (Don’t feck about counting the tonnage on each pin, bang ‘em all in) and a 2:1 pull using a pulley.

That is for another post though.

If all else fails you can do what many other people do. Hammer a GAP into the ground, hook up a winch and hope for the best. The worst that can happen (using your Tirfor in this scenario) is that you will winch up your GAP’s (Known in the trade as a Bordon Spider.)

On bigger (A Vehicle recovery) jobs the consequences of getting it wrong will result in massive damage and/or serious injury.

Safety brief:

Don’t handle steel wire rope with bare hands.

Don’t step over a winch rope. If you must cross one. Stand on it.

Hope this helps.
 

WonDERR

Clanker
Brilliant, thanks Arte et Marte - just what i needed to know. Makes you wonder about the similar size GAPs that are marketed to land rover owners. I shall seek out another small GAP - much easier to move/store than the big one. I have a snatch block which I should have mentioned re tirfor. I remember standing on the rope to cross it from using the big GAP to set up a death slide as an army cadet aged16!

if you're interested i found a picture of my GAP at http://www.anchorsupplies.com/small-anchor-kit.html I might buy another if combined you guesstimate they'll work for a 110!
 

Arte_et_Marte

ADC
Moderator
Crikey they look a bit feeble mate!

But I guess the manufacturer can give you an accurate WLL (working load limit) for each plate

Worst case scenario (not really an untypical job):

Your 110 Defender is bogged in deep mud, its lost a front wheel and needs dragging up a 45 degree slope.

RR = 1.5T
DR = 0.5T
GR = 3T
SF = 1.25T

Your EP is 6.25 tons

Given your little Tirfor winch, (1.6T) You wouldn't winch your vehicle out regardless of the number of GAP's you bang in.

A 3:1 ratio (using a second snatch block) would only give you a 4.8T pull. Not enough. And of course on any multi pulley (3:1 or 2:1 pull) you are drastically reducing your Tirfor winch rope length, which isn't that long to start with.

Aghhhh. Nightmare. :frustrated:
 

ugly

LE
Moderator
I seem to recall being taught to angle the pins across each other in X's to get a bigger bite but it was a brief bit on a course 30 years ago! AEH being the TLA! The advantage of using them is where BFO trees aren't available or where they may be pulled over by the load.
 

Arte_et_Marte

ADC
Moderator
I seem to recall being taught to angle the pins across each other in X's to get a bigger bite but it was a brief bit on a course 30 years ago! AEH being the TLA! The advantage of using them is where BFO trees aren't available or where they may be pulled over by the load.

The X over is correct mate, and the way that the Ground Anchor Plates are designed make this possible.

Trees are difficult. Leave the fir trees alone as there are no deep roots there. A deciduous tree with a trunk of 18" diameter will give an anchorage of about 20T. As long as the tree is protected with 'skidding' (basically 4" x 2" planks) it is an acceptable anchor point.
 
To be honest the best ground anchor I ever used was the bucket of a CET. I hope that helped ;)REgards Holdfast :-D
 

ugly

LE
Moderator
I have a vague recollection of using the AEH for anchoring gyn and shears for improvised bridging which was 30 years ago. I wonder if that field engineering is still taught. Back on topic there is a reason the civ div green laning mud pluggers have big warne winches mounted front and rear, rated usually to pull the vehicle out of the sticky stuff using mother nature. I have found the tall jacks useful and daisy chaining wagons to pull out stuck ones and rarely are trees too well protected, a strop sock through which the SWR is fed seems to be the norm. Avoid Beech trees, Birch trees and any ring coppiced type trees like chestnut, bugger all root ball.
 

ugly

LE
Moderator
I have a vague recollection of using the AEH for anchoring gyn and shears for improvised bridging which was 30 years ago. I wonder if that field engineering is still taught. Back on topic there is a reason the civ div green laning mud pluggers have big warne winches mounted front and rear, rated usually to pull the vehicle out of the sticky stuff using mother nature. I have found the tall jacks useful and daisy chaining wagons to pull out stuck ones and rarely are trees too well protected, a strop sock through which the SWR is fed seems to be the norm. Avoid Beech trees, Birch trees and any ring coppiced type trees like chestnut, bugger all root ball.
 
Trees are difficult. Leave the fir trees alone as there are no deep roots there. A deciduous tree with a trunk of 18" diameter will give an anchorage of about 20T. As long as the tree is protected with 'skidding' (basically 4" x 2" planks) it is an acceptable anchor point.

That's what the recce mech in the foden thought too. Shame it was DPTA and any root system in sand is shallow as shite.
Oh how we would have laughed, as the sod off big tree came down, except we were in the wolf he was supposed to be recovering when he got stuck himself......
 

Arte_et_Marte

ADC
Moderator
That's what the recce mech in the foden thought too. Shame it was DPTA and any root system in sand is shallow as shite.
Oh how we would have laughed, as the sod off big tree came down, except we were in the wolf he was supposed to be recovering when he got stuck himself......

We have all been there.

Me, more than once. :rolleyes:
 
I have a vague recollection of using the AEH for anchoring gyn and shears for improvised bridging which was 30 years ago. I wonder if that field engineering is still taught. Back on topic there is a reason the civ div green laning mud pluggers have big warne winches mounted front and rear, rated usually to pull the vehicle out of the sticky stuff using mother nature. I have found the tall jacks useful and daisy chaining wagons to pull out stuck ones and rarely are trees too well protected, a strop sock through which the SWR is fed seems to be the norm. Avoid Beech trees, Birch trees and any ring coppiced type trees like chestnut, bugger all root ball.

It was 10 years ago ;)
 

ugly

LE
Moderator
It was in the 1950's according to my late father in law. Mind you the manuals we had in the 80's were issued about then!
 
I used the same manual in 95 that my old man used in the late 60's. Field engineering is timeless!
 

WonDERR

Clanker
Crikey they look a bit feeble mate!

But I guess the manufacturer can give you an accurate WLL (working load limit) for each plate

Worst case scenario (not really an untypical job):

Your 110 Defender is bogged in deep mud, its lost a front wheel and needs dragging up a 45 degree slope.

RR = 1.5T
DR = 0.5T
GR = 3T
SF = 1.25T

Your EP is 6.25 tons

Given your little Tirfor winch, (1.6T) You wouldn't winch your vehicle out regardless of the number of GAP's you bang in.

A 3:1 ratio (using a second snatch block) would only give you a 4.8T pull. Not enough. And of course on any multi pulley (3:1 or 2:1 pull) you are drastically reducing your Tirfor winch rope length, which isn't that long to start with.

Aghhhh. Nightmare. :frustrated:

Thanks for the advice, but given what I actually do, realistically i think the worst case scenario you describe is very unlikely - you're right, the wire is too short. What really intrigues me though, is that the tirfor tu16 or t516 (both 1.6T) is the winch that many of the land rover off-road trouble-seeking enthusiasts seem to have (unless they rely on electric winches).
 

B42T

LE
Imagine my disapointment when I checked this thread out and found out it had nothing to do with Belize
 

12345dave

Clanker
Thanks for the advice, but given what I actually do, realistically i think the worst case scenario you describe is very unlikely - you're right, the wire is too short. What really intrigues me though, is that the tirfor tu16 or t516 (both 1.6T) is the winch that many of the land rover off-road trouble-seeking enthusiasts seem to have (unless they rely on electric winches).


I have seen those plates for sale at some of the Land Rover summer shows. I am lead to believe that they are designed as anchors for guys used on masts by the Scalies.

I've been getting stuck in mud (Green Laning) for over 20 years, and i dont think I'd trust one of those not to come flying through the windscreen!

Depending on your budget, electric winches can be purchased at a reasonable price.
 

WonDERR

Clanker
I have seen those plates for sale at some of the Land Rover summer shows. I am lead to believe that they are designed as anchors for guys used on masts by the Scalies.

I've been getting stuck in mud (Green Laning) for over 20 years, and i dont think I'd trust one of those not to come flying through the windscreen!

scaley kit? I wondered. Be interesting to test 2 of those small pates in a V shape and see what happens! ever seen these in use? http://www.island-4x4.co.uk/ground-anchor-db1314-p-7950.html
 

12345dave

Clanker
For years, i used to carry a "proper" RE plate, 8 pins, and a sledge hammer, along with a T35 tirfor. I never needed to use them. Not once.
One of the guys in our group carries a foldable, self digging anchor, which we have tried a couple of times, and its worked very well. He paid about £80 for it, from Germany.

All i carry now is 100' of plasma rope on my leccy winch, with 2x 100' plasma extensions in the back, with a few shackles & strops. There is usually a tree/rock/gate post within range.

Dave
 
Top