Getting unstuck

[DanielJRioux]

[font "Georgia"][size 5]How To Get Your Car Unstuck[/size][/font][font "verdana,geneva,arial,helvetica,sans-serif"][size 2]
Even that shiny new 4X4's gonna get stuck - here's how to get it out!

Around here, there's only two seasons - dust and mud - and your search for a place to enjoy them is going to lead you into some pretty remote areas before you get back home. Remember, other than bulkin' up your wallet, that triple-A card you're carrying is about useless on the back-roads and beaches while you're traveling in Mexico.

[font "verdana,arial,sans-serif"][size 1]Sand:
"As soon as the car starts to sink, stop," says Marv Felwell, owner of 4X4 Tuff (www.4x4tuff.com), a custom off-road and sand dragster shop in California. "Put something under the wheel in the direction you want to go. Wood blocks, branches... a lot of things will work." (Even floor mats in a pinch.) Don't floor it. "If you spin the tires, the car will bury itself," says Marv. To increase traction and widen your "footprint," lower tire pressure by five to 10 psi, then pack detritus behind the tires, straighten the wheels, and follow your tracks to the road. A push will help here, too, but make sure your girlfriend takes off her heels first.[/size][/font] [font "verdana,arial,sans-serif"][size 1]Mud:
There are lots of good times to be had in the mud, but very few involve rope, rubber, and two-by-fours. To get your slop-happy pig back on the tarmac, build a simple gadget called a mud ladder. You'll need to cut a two-by-four into ten 18-inch lengths; then line 'em up and drill holes near each end. Thread long ropes through, knotting the rope after each "rung" to form your ladder. "Put that under the drive wheel [the one that's spinning] and it'll dig you right out," Marv says. The tire will climb the ladder as the motion pushes it down to stable ground. If you're still stuck, entice a sexy passerby to join you in the mud until help arrives[/size][/font]
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You can also get some big guys to push you out! What was your worst time being stuck?
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[gdn443]

That mud ladder is something else. My worst time 4 wheeling was in 75 when three of us decided to go along the blue trail. Went up the moutain and was trying to go down the other side. Took a stream bed wrong and the front left tire dropped and the right rear tire came off the ground. I was stareing at 100' of open air with trees mixed in. We sloowly got out and hooked a chain to the guy behind me and then to the guy behind him and pulled out. I still have a picture of that truck over my computer.
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[DanielJRioux]

That would be a sight to see your truck hanging over the edge like that. Thank god you got out of that all right.
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[Kraizee_Skot]

[font "Comic Sans MS"][#ff4040]You should try to get that pictured scanned and post it up. That would be cool to see, but it sounded like it wasn't too fun.[/#ff4040][/font]
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[gdn443]

Sorry Kraizee Skot, I only have a pic of the truck not my young foolish ways.LOL[]
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[Kraizee_Skot]

[font "Comic Sans MS"][#ff4040]I myself have gotten into some nasty predicaments in my truck also. Makes you think for a minute why you would even try anything like that doesn't it? For some odd reason I keep doing it though.[crazy][/#ff4040][/font]
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[RonPaulFan]

Getting unstuck is best done before getting stuck by making wise choices.

I bought a good vehicle choice and then bought extra sets of wheels and sets of the best tires optomised for traction for various terrains since no one design does everything best.

Every characteristic of tires is a compromise and when you compromise with all of the attributes, each is less than what is possible. Most people go for good tread life for economy, but at the compromise of less traction. All of my tire choices have very poor tread life and a softer rubber that has best traction.

Of my off-road optomised sets, one set is for ice and snow and has done amazingly well this past winter and I've tested and proven them to have grip on ice and snow and even climbing at speed in a blizzard.

The other set is untested for soft sand that can be a challenge for even the experienced with vehicles good for that.

I have a theory that my tire choice will allow them to drive on top of the sand easily without sinking in and without creating ruts to constantly climb out as with the aggressive tread types which are effectively making a flat beach into work that's the same as driving uphill and using lots of power and always on the verge of being stuck.

That's the way it is for most with the problem being that it digs in more whenever the drag is greater than the traction and it's actually digging and climbing out of the ruts it digs all the time with being near the threshold of digging in too much and being stuck which will happen as soon as some conditions line up to make it more difficult like turns, inclines, towing and / or softer looser sand.

I'm looking to test my sand traction on some local sand near Sandy, Utah to gain experience and confidence to make for a better first surf fishing experience for when I take vacation time and want everything to work well.

Anyone know a good place to test them near me?

My theory is the key is to compress the sand for it to behave like a solid road surface instead of trying to have grip on the sand with aggressive mud tread which only makes the sand flow and exhibit it's fluid properties as sand has both properties.

Take two glasses, one in each hand, one with sand and one with water. Have a pan under each. Slowly tilt each to pour the contents into the pans. The water flows as a fluid and so does the sand almost exactly the same. They are both fluid.

Now, place the palms of your hands on top of the surface of each that is in the pans. The water only exhibits fluid properties and the flat palm of your hand goes to the bottom of the pan. But, the sand also has solid properties and under the compression of the flat palm of your hand, you can't compress the solid sand to push through it to the bottom of the pan. Now, with your fingers poking downward, push them onto the surface of the sand. Your fingertips will easily touch the bottom of the pan as the sand moves away like water.

Likewise, knobby tires which have excellent off-road traction on everything else, will be like your fingers causing the sand to flow and exhibit it's fluid properties.

That's fine for mud because under the slicker, slimy mud on top, there is firmer dirt below. But, for loose beach sand, below the surface is more of the same loose beach sand and you are digging in enough to use propulsion in the fluid that sand can become.

Given enough power, I see it works like a paddle wheel on a river boat (sand can have fluid properties like water and we know boats can go fast with propulsion in the water) that is used in sand drag races.

But, speed limits on the beaches for surf fishing are often only 25 MPH and the purpose for the driving on the sand for me is to facilitate surf fishing with optimization for not getting stuck rather than drag racing though I'm sure tread that makes sand exhibit it's solid properties under compression rather than it's fluid properties will still allow for very high speeds (for desolate beaches without the speed limit).

It's all theory now, but I'm ready to test it as I have the vehicle and the sand tires and surf fishing equipment. The main thing I don't have is experience as it will be my first surf fishing vacation.

Anyone here an experienced surf fisherman? Let's go surf fishing!
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[RonPaulFan]

At the time of this post 202 people have read my above post yet there are no conversations, so here is a conversation starter:

Anyone like physics?

Let's have your thoughts on the physics of getting a vehicle unstuck.

Why?

Understanding the physics of our task enables us to optimize what is working for us which is important in difficult situations where getting a vehicle unstuck is marginal or won't happen.

Next proposed (participation) topic: What is the difference between tow straps and recovery straps and how are they most effectively used? You start.

I'm a scientist. Not the new sort of "consensus science," but the traditional definition of science.

What's particularly interesting to me on what works and how what works better is counterintuitive. Common sense has it that what works best is what the experienced are doing. But, are they doing that because they really know? No. They just figure it must be best because it looks best (as in the previous example of aggressive knobby tread on loose sand) or everyone does it that way.

On the topic of getting vehicles unstuck, my observation is there is often a lot of emotion, frustration with what doesn't work and even end-of-the-world sort of desperation which is not the best time to discuss physics even though it is often exactly what they need.

Example: I was reading an article of a death from a couple being stuck in sand long enough for exposure to be a factor. The rescuers recovered the vehicle simply by letting out most of the air pressure out of the tires and driving off without need for any other action. If the elderly couple had this simple knowledge, there wouldn't be the death.

I have more such examples and some in my experiences. What are yours?

Still not replying! The Russians got to you, too! "The Russians Did It!"

What is the physics of getting a vehicle unstuck with a strap?

Your turn. It's not a conversation with just one person posting.
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[RonPaulFan]

What is the difference between tow straps and recovery straps and how are they most effectively used? Understanding the physics.

A tow strap is designed for towing a vehicle that is free to easily roll on a good surface.

A recovery strap is designed for pulling a vehicle out from being stuck which takes considerably more force.

The difference is the recovery strap is designed to stretch.

A chain is an example of almost no stretch. Let's compare.

A chain or a tow strap or a recovery strap can tow a vehicle. But, for recovery of a stuck vehicle, it's best to use a recovery strap.

Without stretch like the extreme example of using a chain, the force that can be used to pull out a stuck vehicle is limited mainly two ways:

1. The limit of traction of the pulling vehicle which might be in nearly the same mud or snow and ice or loose sand as the stuck vehicle, so not only does it need to have enough traction to not get stuck itself, it also has to have enough additional traction for the other vehicle and that it is stuck means even more traction which it might not have on a surface of poor traction.

2. Force. There is a limit of force that should be used to pull out the stuck vehicle.

If the required force can't be achieved with traction alone, having slack in the strap allows the pulling vehicle to gain some speed before encountering the resistance of the strap attached to the stuck vehicle. That short distance allows the pulling vehicle to gain momentum even when the low traction would be otherwise insufficient to getting both vehicles moving together as with a strap without slack. With a chain, the kinetic energy of the moving vehicle suddenly is imparted to the location on the vehicle to be recovered with a high peak of force of very small duration. Such high force of short duration is called impact. Impact has a tendency of being destructive and is not the sort of force conducive to moving things.

Let's examine that. Let's say that six thousand foot-pounds of energy is sufficient to move the stuck vehicle from being stuck. My rifle has more than six thousand foot-pounds of energy. If I were to shoot the stuck vehicle from behind, it would not budge the vehicle at all. Instead there will be a hole through it. That's an extreme example, but the energy of a moving vehicle suddenly transferred through a chain that suddenly becomes taught will likewise be impact. It can bend the stuck vehicle frame without moving it from being stuck and the tow vehicle frame can be damaged and it can even exceed the breaking strength of the chain. This experiment done in thought shows that impact or a high peak force over a very short duration is not useful for recovery and there is little benefit to getting this added short duration peak of force when taught chain force of just traction alone is insufficient.

Stretch is the key to recovery straps. They are designed to stretch by the choice of a material that stretches. Some tow straps also stretch and some have little stretch, so choose a recovery strap. Stretch works very powerfully for recovery by storing the energy of momentum when the slack is taken up. Instead of the tow vehicle coming to a sudden stop on a chain and useless and damaging impact imparted on both vehicles, the energy is stored to allow a much lower peak of force that is spread out over a much longer time duration and that is useful to pull out the stuck vehicle.

Now that we know that stretch works, we know we want to maximize stretch by purchasing the right recovery strap or straps. Pick one that is specifically a recovery strap rather than a tow strap. For safety, it has loops on the ends and no hooks to come dangerously undone and should be fastened properly. Remember the energy of momentum is stored in the stretch, so if a hook comes loose, it can have the energy of a bullet or more and act similarly (more on that in another post, if requested). A recovery strap of greater working load capacity than necessary will have reduced stretch, so more isn't necessarily better. A recovery strap of longer length will have more stretch and can store more energy from greater momentum without a greater peak force. That means less impact and more useful duration of pull which means it can pull out a vehicle that is stuck worse. Buy the longer length by choosing the longer recovery strap or several you can connect end to end with technique to not have a knot get too tight to come apart again (more on that in another post, if requested).

I have several recovery straps to connect end to end for both more stretch (more capacity to store the energy of momentum) and more length. The extra length can be advantageous in that it might allow the recovery vehicle to pull from different terrain for more traction instead of getting into the same slimy mud or loose sand or ice patch as the stuck vehicle. It will allow a vehicle with otherwise insufficient traction to pull out the stuck vehicle
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[fishguy01]

Sounds good, anyone tried using the car mat? Does it work?
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[RonPaulFan]

[quote fishguy01]Sounds good, anyone tried using the car mat? Does it work?[/quote]

I'm more into preparedness to not get stuck. If you have to use a car mat, then you're already stuck, so hopefully it is just one hole instead of the terrain like being in loose sand because you would have to use the mat many times.
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[letscruise84]

Getting a good recovery winch like Warn Winch is a must.
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[RonPaulFan]

Since we're in a fishing group, I'll address that from my perspective on a trolling motor or using oars for my fly fishing pontoon boat or using an engine driven ice auger or muscle powered. I use oars. I use a Nils auger and muscle power. It's great for fitness.

On the winch, I have a small lightweight come-a-long as my alternative to powered. My thinking is I put emphasis on traction in a premium and highly capable vehicle and optomised tire choices for the terrain instead of emphasis on getting unstuck and that is much better than the other way around.

But, I'm still into preparedness and the come-a-long fills that unlikely yet possible need well particularly since I expect it to never need to be used and I want it to not weigh much.

If on the unlikely chance it is needed, it can pull the same amount and it will just be good exercise for me. It's reliable. It's more versatile since I can connect to any recovery point on the vehicle and then put it away when I'm finished.

Traction is so good that I won't need a winch to help get others unstuck and a recovery strap will be sufficient and it's also lightweight, reliable and can be put away after use.

But, you're right in recommending a winch for mostly everyone else. It is a good choice.

I'm also thinking of loose sand. In traveling far in loose sand and getting stuck, there is just a lot more loose sand to continue on or to turn back and it's all about the same, so if you get stuck, getting unstuck just to get stuck again and again doesn't really solve the problem that good traction solves.
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