Though Mors Kochanski popularized the use of the flip flop winch, it appears it was used during World War II, by the British Army to help them get their vehicles out of the trenches.
Using nothing more than rope and two four inch thick logs, the Flip Flop Winch really is an ingenious machine, giving the operator a tremendous mechanical aid in helping to get your vehicle unstuck.
For the outdoorsman, this skill is definitely a must have
Here is the guys from Northwest Bushcraft demonstrating this ingenious device.