M925A1 Stuck on my own property. DOH!!! Winch to the rescue!

[Truckoholic]

Cool stuff to look out for....Like a little test drive around the place....That what hiways are for....Nice recovery....Going to plant more trees??

Ha ha. I bought this property a year and a half ago, and already the trees in the meadow have grown far bigger than they were when I bought the place. Part of me was irritated that my meadow was being overtaken by trees, and I thought about pulling them all out. But at the same time, I thing having a grove of trees on my property later might be more beneficial than having an open field that is too wet to farm anything on anyway.

And yeah, the only reason I took the little drive around the meadow, was because the truck wasn't registered yet, and I was going to be driving it on the highway the next day for its first time in 5 years after doing a bunch of mechanical work to it, and wanted to make sure things were still looking good.

 

[therooster2001]

Camels on wheels... Lol.

That sand anchor looks like the pull-pal, but still like a DanForth. I know 'jpg' used one on a sandbar, very similar to the way these guys used it. I am in Colorado with NO anchor, and no West Marine around. Guess I could get one, and do the stress test, as I see a lot of discussion but no real publishable results. I see a lot of religious debates on the pull-pal, which is really boiling down to just the expense (which the opposition is how much would a tow cost...).

I did some google research on winch theory and pulling power vs anchor holding power (which is a bit subjective as holding power for the Danforth in "average bottom conditions" just doesn't translate to being stuck in 2 feet of mud). As I dove into this, I realized I am a bit under educated, and am going to research a bit more. Winch power and wraps on the drum make a huge difference on the pulling power, and I'm not sure that being stuck in the mud down 10 inches can easily be measured (the military has a chart on grade), nor the tensile strength affecting an anchor, so I am going to have think on this one. I'm a bit scientific on this subject and want to make sure I don't make wild claims, but back it up with something material. If someone has done the homework, I'm all about listening..

Some interesting pages:

http://www.danforthanchors.com/hitensile.html
http://www.innovation-engineering.co.uk/winch_theory.htm
http://www.pacificmarine.net/marine-deck/winches-and-hoists/how-to-size-a-winch.htm
http://www.pullpal.com/ppspec.html

From one of our peeps, not about winch sizing necessarily, but about snatch block, dead weight guidelines and general math on the pull theory, which explains some of the direct forces on the anchor (just good knowledge)
http://www.steelsoldiers.com/showth...-for-front-winch&p=42318&viewfull=1#post42318

Using a snatch block on the anchor would be even worse for it's "holding power".

As someone stated in that thread, math is hard...

Apologies for the hijack, let me know if we should move this to another thread.

 

[therooster2001]

Wow, there were like 6 posts since I started writing my novella above. Nice article on the hold power (and from West Marine!) Ha!

 

[rhurey]

I asked Lewmar (They make Delta Anchors) if they have a size to holding force table.

They sent me an "anchor size" to "Foot of boat length" table, but not quite what I was looking for. I'm sure they have it, but the question is can I find someone customer facing who has it.

 

[Truckoholic]

This discussion is great, and is relative to my original post. So keep it up It's all very interesting!

 

[jpg]

The engineering department should be able to tell us how hard you'd have to pull to break the anchor, given a uniform holding ground like sand or mud, and a straight-line horizontal pull. This type of pull never happens in boating, so Customer Support won't likely have this info handy. Boats constantly shift the direction of pull, and they pull up, not just horizontally.

On a boat, when the wind shifts, the boat pulls from a different direction. Anchors are designed to cope with this by shifting in the holding ground. So if you use an anchor to hold a pulley that changes a line's direction of pull, the anchor will shift to match the direction of pull that it "sees". This should work reasonably well.

The danforth is one of many anchor designs. They all have strengths and weaknesses. The danforth is the only one that folds flat for storage, which is why I recommend it for us. I'd go for the lightest one that can handle the pull of your winch. Lighter is easier to handle. The harder you pull, the deeper it digs in, so even a small one should dig in enough to make your winch the limiting factor.

 

[rhurey]

I was most worried about breaking the eye on the top of the anchor if you get an anchor that can hold 1500lbs and try to attach a M925 to it.

 

[jpg]

I was most worried about breaking the eye on the top of the anchor if you get an anchor that can hold 1500lbs and try to attach a M925 to it.

Agreed.

Remember in boating, much of the pull is up, toward the surface, so they worry about the amount of pull required to pull the anchor up out of the bottom. We pull horizontally, and boating anchors are not marketed for that application, so the straight horizontal pull capacity is not readily available.

My anchor is high tensile steel, and the eye seems to have about as much "meat" as the D ring on the truck bumper. I'd be very interested to hear what the engineers say the working load is for a straight horizontal pull in uniform ground.

I should mention again that my truck is just a little M1010. You guys with the big trucks have far more weight, winch, wheels and ground clearance to work with.

For any winch newbies reading this: safe winching always assumes that something could break, so no people are allowed in the danger zone in case something gives way when a cable is under tension. When something snaps when a heavy steel cable is under tension, it can whip around and sever limbs and/or kill people. You should never trust winching gear not to break, but this is especially true for the old surplus gear we use. Corrosion can be hidden in places like under fittings, concealed until you put a strain on your cable. Get proper training before you get involved in heavy winch operations. Be safe.

 

[salt6]

The M113 had a kit like this.

Capstan Kit.
A capstan kit NSN 2540-00-933-3570 can be used to ease the APC over steep or slippery banks and through boggy areas. If the APC does not have a kit, one can be ordered using the national stock number. The kit has two adapters permanently bolted to the hub of each drive sprocket, two capstan drums (bolted on each adapter [with a T-bolt]), four 100-foot and two 50-foot lengths of 1-inch nylon rope with shackles, and two marine anchors with recovery cables.
To use the kit:
Bolt drums with T-bolts to the adapters, making sure that laterals are locked.
Thread a length of rope through the outside flange of each drum.
Make two or three turns over the end of the rope to anchor it, being sure that the rope extends from under the drums.
Set the marine anchors in line with the drums and press them into the ground to give them a good start.
Eliminate all rope slack before attaching the ropes to the anchors.
Apply vehicle power slowly until the tracks are turning equally. Keep a slow, steady, equal pull so that the anchors will dig in evenly.
As the drums winch the ropes, the APC will move out. Use a guide to make sure that the rope winds up properly.
The anchors can be used side-by-side or in tandem. Because the anchors may go underground, be sure to attach the recovery cables to them before pulling. Recover the anchors by pulling the recovery cables with the APC.

http://www.globalsecurity.org/military/library/policy/army/fm/7-7/Appl.htm#s3

 

[rhurey]

Remember in boating, much of the pull is up, toward the surface, so they worry about the amount of pull required to pull the anchor up out of the bottom. We pull horizontally, and boating anchors are not marketed for that application, so the straight horizontal pull capacity is not readily available.

Isn't that the point of a chain lead and setting scope correctly? So your anchor only "sees" horizontal forces? (And the reason we need to let out more line as the tide rises, cause it's moving the boat up.) The derating on holding power for incorrect scope is pretty nasty.

 

[jpg]

Isn't that the point of a chain lead and setting scope correctly? So your anchor only "sees" horizontal forces? (And the reason we need to let out more line as the tide rises, cause it's moving the boat up.) The derating on holding power for incorrect scope is pretty nasty.

Right. But if the boat pulls the rode straight, say due to a strong wind, the holding power drops dramatically. If a strong swell causes the boat to tug on the line, that also reduces holding power. These issues don't apply when we use the anchor to winch a truck. This is why the usual anchor specs don't tell us what we need to know.

 

[Truckoholic]

I was in Sportsman's Warehouse this evening, and happened to see that they had some Danforth style anchors in there. These were 18 pounders, rated for up to 34 foot boats I think. I looked it over real good. Just based on my experience with the strength of steel, I would expect one of those ones to withstand about 6,000 pounds of horizontal force in one direction. The only potential issue I saw as they are designed, is that the tangs or whatever you call them, would not be able to go at a steep enough angle. Those particular anchors only allowed something like a 25 degree angle, and with the tangs already being as short as they are, they really wouldn't dig in very deep, and I could see you just pulling the top 8 inches or so of dirt right along with the anchor. But if you get too much of an angle, then it won't dig in right, or it will just be bent from the forces exerted where they shouldn't be. So I can see where using an anchor that was designed for use by a boat, could very well work amazingly well, but might need a little modification here or there. I ended up not going and trying to buy the danforth anchors I found on Craigslist yet. But now after looking at the ones at Sportsman's Warehouse, I really think it might be worth having one or two onboard the truck behind the seat or something for emergencies where even 6,000 pounds or so of pull will be enough to get you out of a mess.

 

[RedBlok]

Have you thought about making some Sand ladders? I know there are companies out there like www.Okoffroad.com I am not endorsing then or connected to them. I was just suggesting looking at their site for ideals. I kind of like the ladder ideal.

 

[VPed]

As for getting stuck in sand (I'm not a mudder), if you have bead locks and supersingles, I think you really have to work at getting stuck if aired down. I use my trucks a lot in deep sugar sand and have not stuck one yet.

On my deuce, I originally had the stock NDT and that was not too good. I then went with 395's on the stock wheels using tubes. I could not air down sufficiently to prevent the tires from sinking in on a climb. If you air down too much, the tire spins on the wheel and rips the tube stem out. Now I have MRAP wheels and tires with bead-locks and I am virtually unstoppable in the sand. I know that is saying a lot and I do still choose my path with care but I hang with Jeepers and most of them have expressed their amazement in my trucks' capabilities.

My 5-tons had super-singles with bead-locks from the get-go. The biggest liability I have now in the sand dunes is the huge overhang to the rear of my M927. That I do have to watch to prevent hanging the butt end up.

The towing and recovery TM does have some great ideas for putting together anchor points. The one using large wooden stakes tied to each other seems like could be combined with a marine anchor to increase the hold potential.

PS: I do have a wrecker for just in case

 

[jpg]

Here is a table from an old Danforth brochure. Note that pound for pound, a few smaller anchors give you more holding power than a bigger anchor of equal weight. For example, for my 18,000 pound winch, 2 20-lb anchors in series would be a good match in hard sand.

The brand has changed hands since. I called the new company and asked engineering our question. They may or may not answer. I asked for working load and yield load. I'm not sure what the relationship is between holding power and working load. I imagine holding power is <= working load, but I'm not sure by how much the differ.

When the anchor doesn't hold, it's designed to bury itself deeper as it's dragged through the holding ground. The idea is that it should eventually hit something more solid and hold.

You can see the whole Danforth Anchoring Pamphlet here: http://www.steelsoldiers.com/showthread.php?140031-Danforth-Anchor-Pamphlet