International Guild of Knot Tyers Forum

General => Practical Knots => Topic started by: NotSure on November 12, 2013, 11:54:53 PM

Title: Rope Winching for off-road salvation
Post by: NotSure on November 12, 2013, 11:54:53 PM
After a cursory search and with bad weather fast approaching, I haven't seen any mention of this yet, so...

When a Versatackle just won't cut it, a "Flip-Flop Winch" is a clever option to consider. It basically turns the Spanish Windlass into a 1-man operation. You just need to pack a long roll of tow rope or strap in your trunk.

Links:
1. http://www.ravenlore.co.uk/html/kochanski_winch.html (http://www.ravenlore.co.uk/html/kochanski_winch.html) (Mors Kochanski's version - the originator of this method)
2. http://www.youtube.com/watch?v=oKC6z24ZgqI (http://www.youtube.com/watch?v=oKC6z24ZgqI) (Michael Lummio's version)
3. http://www.youtube.com/watch?v=8g9oOMnwqo4 (http://www.youtube.com/watch?v=8g9oOMnwqo4) (Dave Canterbury's version)

Of those three links, I think Mr. Lummio has the best version because it minimizes sideways torque on the "Drum" log and doesn't pinch the rope anywhere. Also, I find his use of a Round Turn with an Adjustable Grip Hitch for the tree anchor quite interesting. His reasoning is sound and is something I might have otherwise overlooked. (Although I'd probably use a couple more gripping turns on the AGH myself...)

Mr. Canterbury's video is excellent for demonstrating how staking the Drum log and temporarily looping the Lever log in place can help, but I really HATE the hitches he chose to anchor with at either end. (the first one is prone to jamming despite what he may believe, and the other is not terribly secure I think).

A Chinese Windlass would be a superior option to the "Flip-Flop", but I can't figure out any easy method of achieving this in the bush. It's just a little brain teaser for now.

Also, I have seen other videos recommending a Tourniquet (ABoK #1258) style of twisting the rope with a stick to raise or pull objects with, but I think this is the absolute worst method to use. It puts a lot of strain on the rope and the stick, and I see it providing progressively LESS leverage the more you twist.

Below, the first image is a still shot from Mr. Lummio's video, the other two are from the Ashley Book of Knots.
Title: Re: Rope Winching for off-road salvation
Post by: [Inkanyezi] gone on November 13, 2013, 12:44:48 PM
There's a substantial difference between mr Lummio's approach and Canterbury's. You can easily see it, and you might then understand that the stakes in Canterbury's approach are there for a reason, a reason that is not present, or if so, to a much lesser degree, in the "original" Kochanski method, shown by Lummio.

In Canterbury's approach, which is amply unsafe, downright dangerous, the rope is wound onto alternate sides of the lever pole, causing leverage on the drum pole, making it tend to swing sideways. That's why he uses stakes to keep it in place, but bear in mind that the demonstration is done without any slope that the vehicle could slide down. Hence the vehicle will stay more or less in place when tension is removed from the line.

The Real World often is a bit different. The Canterbury drum pole will swing swiftly and remove those stakes in a jiffy when the vehicle slides back down a slope. It may also sever the legs of the operator when it swings back.

Kochanski and Lummio wind the two parts of the rope neatly side by side, never causing much sideways leverage on the drum pole. Both parts are essentially in line, as seen from above, never at a large distance from each other, as in the Canterbury application. The distance between where the rope is attached to the drum pole in Canterbury's approach is a major flaw, and the method should not be used in that way.
Title: Re: Rope Winching for off-road salvation
Post by: Sweeney on November 13, 2013, 05:43:45 PM
There's a substantial difference between mr Lummio's approach and Canterbury's. You can easily see it, and you might then understand that the stakes in Canterbury's approach are there for a reason, a reason that is not present, or if so, to a much lesser degree, in the "original" Kochanski method, shown by Lummio.

In Canterbury's approach, which is amply unsafe, downright dangerous, the rope is wound onto alternate sides of the lever pole, causing leverage on the drum pole, making it tend to swing sideways. That's why he uses stakes to keep it in place, but bear in mind that the demonstration is done without any slope that the vehicle could slide down. Hence the vehicle will stay more or less in place when tension is removed from the line.

The Real World often is a bit different. The Canterbury drum pole will swing swiftly and remove those stakes in a jiffy when the vehicle slides back down a slope. It may also sever the legs of the operator when it swings back.

Kochanski and Lummio wind the two parts of the rope neatly side by side, never causing much sideways leverage on the drum pole. Both parts are essentially in line, as seen from above, never at a large distance from each other, as in the Canterbury application. The distance between where the rope is attached to the drum pole in Canterbury's approach is a major flaw, and the method should not be used in that way.

Having watched both videos and then tried this with 2 pencils (a lot less dangerous than 2 trees!) there is a significant increase in the sideways pressure using Canterbury's method as Inkanyezi points out - I certainly wouldn't use it though the principle looks useful for occasions where something heavy needs moving even in the back garden.

Barry
Title: Re: Rope Winching for off-road salvation
Post by: TMCD on November 18, 2013, 02:22:50 PM
I watched Dave Canterbury's video and that seems like A WHOLE LOT OF WORK! It seems rather clumsy too, I think I'd devise a trucker's hitch that could achieve the goal of moving that vehicle out to a clear spot. If you've got a solid tree, which Dave had, you can produce a reasonable trucker's hitch that should be able to move that ATV without having to go through the motions he went through to move it, IMO of course.
Title: Re: Rope Winching for off-road salvation
Post by: struktor on November 18, 2013, 08:09:03 PM
The First Tackle. Eskimo landing a walrus.
http://archive.org/stream/cu31924003643040#page/n65/mode/2up
''The origins of invention: a study of industry among primitive peoples'' by Otis T. Mason,  1902

Working a Spanish windlass:
http://www.flickr.com/photos/mcmillanportraits/3221110864/

Effects of breaking a towline.
http://youtu.be/hAY0oVwuzNY?t=2m00s
Oil rig anchor chain snaps near death.
http://www.youtube.com/watch?v=nGyvZSnjVLc
Title: Re: Rope Winching for off-road salvation
Post by: Bob Thrun on November 22, 2013, 06:14:54 AM
It seems to me that the maximum force the "Flip-Flop Winch" can exert is the force it takes to drag the logs across the ground.  This depends on the weight of the logs, which is limited by what a  person can lift. Is there some way of anchoring it to a tree?
Title: Re: Rope Winching for off-road salvation
Post by: [Inkanyezi] gone on November 22, 2013, 10:10:19 PM
It seems to me that the maximum force the "Flip-Flop Winch" can exert is the force it takes to drag the logs across the ground.  This depends on the weight of the logs, which is limited by what a  person can lift. Is there some way of anchoring it to a tree?

It is anchored to a tree, and it can exert much more force than to drag the logs. However there are opposing forces on the drum log from the two ends of the line, and therefore, both parts should preferably be wound side by side onto the drum, and not be split widely apart.

Think of it like a winch put mid-line. It pulls from both ends, and the force depends on the length of the lever log and the diameter of the drum log. If the drum is 1/2 ' diameter and the lever is 5 ' length there's 10 times gain of force. Evidently, the most fruitful way to increase force is to decrease drum diameter.
Title: Re: Rope Winching for off-road salvation
Post by: Rich on November 25, 2013, 01:27:03 PM
NotSure, thank you, this was new to me, as were comments on the Lummio video suggesting blankets or similar on the rope to reduce the risk of injury if the rope breaks.

One man, one rope and, if you can find a fallen tree to cut in half, one sawcut. Why whittle a Chinese Windlass ?

Lummio pulled a a c300Kg load on hard, flat, ground. I don't think he could pull a 3500Kg 4X4 up a muddy bank without more mechanical advantage.

More MA can be obtained by :-
#1 Reducing drum diameter (Inkanyezi), there is a limit to this.
#2 Extending lever pole as suggested by Lummio. But the effort MUST be applied to the END of the pole. Since people are
     not 7M tall we need another device. A second, compounding, flip flop ?
#3 Block and tackle or some other in line arrangement.

Or combination thereof.     
Title: Re: Rope Winching for off-road salvation
Post by: roo on November 25, 2013, 04:15:13 PM
An unusual application of a windlass:

http://www.youtube.com/watch?v=c0_oKHARhXw

Title: Re: Rope Winching for off-road salvation
Post by: Rich on November 26, 2013, 01:15:12 PM
#1 Horizontal operation, vertical drum, this is a capstan.

#2 If you don't have a convenient tree for the flip flop you will have to create a ground anchor anyway, so why
     not use it in your wheel and axle ?

#3 Pros.
     Wheel spoke, however long, rotated from its end.
     Continuous rotation.
     Facilitates multi-person operation.

#4 Cons
      Auger needed for an accurate, cylindrical, hole.
      Brake needed to enable you to stop for a fag.

Can anyone identify the car to enable a load estimate to be made ?