Double Pully

[msb1766]

Can anyone tell me how to set up a winch cable into a double pully set up for more power.

 

[Stumper]

A fixed/static/stationary block(pulley) simply changes the direction of pull. A movable block allows for multiplication of force by increasing the distance the line is pulled. (100lbs of force applied over 2x,3x,4x, the distance results in 2x ,3x,4x the force-ignoring frictional losses). The 'how' of setting up the blocks includes many posssibilities (Luff Tackle, Gun tackle etc. etc.) Just remember that for increased pull you have to have a block 'float' after that the more loops of rope in the system the more multiplication you recieve.
To get the maximum out of only 2 pulleys. Attach one at midline and the other to your"anchor" pass the line through the anchored pulley then back up to the floating pulley at midline. When you pull on the tail this arrangement it will give you a 3/1 multiplcation effect. (Essentially a gun tackle arrangement-named for its use in moving cannons aboard ships with the minimum of equipment)

 

[Tim Gardner]

If you do not have a copy of Clifford W. Ashley's book The Ashely Book Of Knots , you can check it out at your local library. There is a section called Practical Marlingspike Seamanship that addresses block and tackle setup. I had an eightfold purchase (total of 16 pulleys) that I used for a while. Without the method he describes in his book the block would not have functioned. I could drag my truck aross the yard with it in gear and the brake set using my hands to power the block.