Mechanical Advantage

[Kevin]

No, not tractors or skidders.

Mechanical advantage using blocks and pulleys.
I don't see this mentioned often and it is handy for winch loading a trailer which so many small operators do here.
I loaded a couple of 12' spruce logs today about 14"dia using pulleys and pulling the rope by hand hauling the logs up a ramp and onto my trailer.
The third was over 20"dia. and required the rope winch but it was easily loaded.
Save your back and try a mechanical advantage.

http://www.btinternet.com/~fourthgill.seascouts/tackle.htm#Luff_Luff

[Chet]

Da last logs I loaded on my trailer using ramps I used a rope too. But I used a lot of mechanical advantage, I used my pickup.  

[DanG]

Yup, mechanical is definitely an advantage. It beats manual, any day. It even beats Manuel on a hot day.
Seriously though, you are right, but if I have a trailer, that means I have my truck, which has a winch, which don't require me to pull on a rope. I do have some blocks and ropes, though, and won't hesitate to use them if I need to.

[Bro. Noble]

And don't forget levers.   I find the levers on our front end loader especially useful

[Kevin]

I give up!  

[Woodhog]

I was thinking of this the other day when I had a big spruce
hung up (first one for 30 years) .      

I was thinking of getting a block and using it for a movable
pulley. i.e. making one end of the winch cable fast to a tree,
hooking the block to the butt of the tree, then the free end
would come back to the winch drum, I think this about doubles the pull on the tree??, however if that is so does it
also mean the cable could break by its normal breaking load being exceeded...      OUCH!!!!    

[Kevin]

The force on each winch line would equal the load, the force on the anchor would double.
I would opt for two blocks for a better MA as in fig 9 Luff.

[Ed_K]

 When I get a hangup, the frist thing I try is to run the cable around the butt a turn and a half to two turns, and try to screw the tree around enough to break the top free. also try using a slid or two to get the butt off the ground and foward in one motion.
Ed

[Kevin]

Good idea Ed, here's a good example of MA from How Stuff Works...

http://static.howstuffworks.com/gif/bt4.gif

[Don P]

The ridge here was lifted on the line of pump jacks that are here shown lowered to be the working scaffold under the ridge. The back rafters over the loft floor were hand set first. Then the clamp on gin pole was hung on them and a suspended block and tackle lifted the front rafter. This was all pretty heavy cypress. Michelle handled the haul line.

[D._Frederick]

Woodhog,

Your post #5, you are correct that your pulley system will double the pulling force to the tree. The tension on the cable will be no more than your winch will pull.

[woodmills1]

Now mentioned twice the theoretical value of tension in the cable would remain constant.  But, I fear the friction introduced into the system would in fact increase tension in the cable.  Now if you have read the thread on tractor winches you could easily see that the truck itself could loose its footings and slide sideways Oh never mind.