Line pull is way more than the breaking strength of the 3/8” GAC, dads says it is upwards of 10 tons and the design has been put through the test over the years.
Some of the winches were built with larger heavier frame and spooled with 200’ of 1/2” cable. Obviously too heavy to be called portable.
Gearboxes are tricky, the more torque that can be generated the larger and heavier they are.
The gearbox ratio has not a thing to do with the rated torque and sometimes you have to make a compromise or a balance between the weight and at the same time the boulder pulling power.
Choose wisely the smaller gearboxes have smaller gears and will be easy to sprip out.
A working ratio from motor to the spool should be between 750-1000:1 when building a winch of this type. Choose your gearbox and sprockets according to the math.
An utmost respect for the unsane amount of pent up torque is a must and take it from there.
Never have we had any problems with the winches we built but one should not be so sure when it come to safety.
A True StoryMy uncle back in his days made a bet that his winch would pull a massive boulder out of the gravel bar just so he could fill in his deep wide dredge hole, the thing was the size of a small cabin or maybe bigger.
Most guys said there was no way that would never happen.
So on the first attempt he hooked it all up and miners came from all around out of the wood to watch this mountain style entertainment.
He set the motor to wide open and set in waiting safely out of the way.
Well, the winch got into a hard pull and that a boulder began to move ever so slightly, then flash the winch shot like a bullet across the river smashin' into a many a pieces against the bedrock embankment.
My dad never will forget that sight. (200+ Pounds of steel flying and exploding into a million pieces)
The anchor chain which was double wrapped holding the winch had snapped.
Being he is our family, if you only knew what I meant, he went home and fixed up another winch that WOULD pull that boulder once and for all.
Matter of fact, he was down there the next day and was going to pull that there boulder. This time he used the biggest chains he could muster up and had been up all night fixing up a new winch.
The spectators all in place, the winch was rigged up again, he fired up the motor and set it to full throttle, then took cover.
The winch started its pulling and the motor started bogging down but no movement on the boulder. The suspense grew.
All of a sudden it began to jerk and shake; sure enough it was a movin' like molasses fresh out of the freezer. No one could believe their eyes.
That boulder came down with the loudest of rumbles that, later was told, the force of the impact could be heard and felt by miners miles away. And all the looker-ons, well, they got themselves a good bath that day.
It was the talk around many a campfires for years to come, still hear it from time to time. My dad will never forget it and he can tell of it far better than I have, I was to little to be a witness.
True story, a family one at that.