Winches

[ch1ch2]

If you do get a winch, consider getting one rated at 2.5 times the weight of the vehicle.
The pictures of a winch pulling a ATV up in a tree may impress those whom have not used a wench but if you are stuck in mud, the weight of your vehicle plus the weight of the mud plus the weight of air. The weight of air is the one that will get you.
Some might think that is a joke but suction can be the hardest thing to over come.
If you have ever seen a cable break...well, you would not be trusting anything small.

 

[GPintheMitten]

Suction is not weight of air. It has to do with the strong covalent bond in water.

 

[ch1ch2]

Suction has everything to do with the weight of air. Somewhere around 14.5 PSI I forget the exact pressure.
I got a mid size BH stuck in the mud. It could not pull itself out. Called in a full size big rig wrecker. It winched itself to the point the front tires were ten feet in the air. We had to wiggle the loader and BH until the suction broke and air could get under the BH.

 

[GPintheMitten]

Ok, so once you got air under the backhoe, the air was able to hold it up?

 

[ovrszd]

Suction has everything to do with the weight of air. Somewhere around 14.5 PSI I forget the exact pressure.
I got a mid size BH stuck in the mud. It could not pull itself out. Called in a full size big rig wrecker. It winched itself to the point the front tires were ten feet in the air. We had to wiggle the loader and BH until the suction broke and air could get under the BH.

I'm afraid I gotta go with GPintheMitten on this one.

What you, ch1ch2, are referring to is vacuum. Nothing to do with weight.

In the end I think we all know the end result.

 

[David P]

I turned an aluminum boat trailer into a utility trailer and scavenged the winch from it and now use it for other purposes. The winch would slide down onto a 2x2 post on the trailer and was then bolted to the post. I use this end of the winch to attach to a tree and the other end to my gator. Works great, although the gator isn't very heavy (6x4).

 

[CobyRupert]

I'm afraid I gotta go with GPintheMitten on this one.

What you, ch1ch2, are referring to is vacuum. Nothing to do with weight.

Uhmmm.....not so fast...
Vacuum is directly related to the weight of the air. They're opposite sides of the coin. If I put a glass upside down on a table and suck all the air out , you could say the vacuum is keeping it stuck to the table, but it's also true that the weight of the atmospheric air pressing on the outside of the glass is keeping it stuck to the table.

It's the old argument about why a sailboat moves, does the air push the sail, or does the vacuum on the opposite side suck the boat forward?

 

[ovrszd]

Uhmmm.....not so fast...
Vacuum is directly related to the weight of the air. They're opposite sides of the coin. If I put a glass upside down on a table and suck all the air out , you could say the vacuum is keeping it stuck to the table, but it's also true that the weight of the atmospheric air pressing on the outside of the glass is keeping it stuck to the table.

It's the old argument about why a sailboat moves, does the air push the sail, or does the vacuum on the opposite side suck the boat forward?

Uhmmm,,,,,not so fast...

If I take a glass, heat it, put it upside down on a scale, and weigh it. With your theory it will gain weight as the air in the glass cools and creates a vacuum??

 

[joefromga]

Surface tension is what you're talking about.

 

[CobyRupert]

Uhmmm,,,,,not so fast...

If I take a glass, heat it, put it upside down on a scale, and weigh it. With your theory it will gain weight as the air in the glass cools and creates a vacuum??

No, it would weigh (mass) the same, because there's still the same number of molecules. No mass is gained when it cools. The force pressing in from the outside would appear to increase, but in reality it's constant, it's just that there is not the same force pushing back from the inside, because the molecules contract as they cool. If it was in a medium that didn't expand and contract as much as air, (or steam) you wouldn't get effects as dramatic as this:

The reason we know the force one experiences with a vacuum is caused by the weight of the air, is because absolute vacuum is the weight of the air (about -14.7 psi). If you were on top of Mt. Everest and sucked all the air out of that glass, or this barrel, the vacuum would be less, (correction: not less, but the force the glass experiences would be less) because the atmosphere would only exert about 4.9 psi on the outside instead of 14.7psi. (if it was at sea level).