This took two 4500lb winches to get out pulling in tandem, yeah I could've doubled the line but it was a little too far for my short 38' line to reach when it's half length and there was another guy there so we just hooked them both up.
It wasn't a true 4500lb pull EACH because we weren't on the first layer probably at most 5000lb combined.
There's more to account for when winching than a 4500lb winch and a 1700lb vehicle (what mine weighs)
You have to account for the different pulls on each layer of the winch the more rope you have on the winch the higher the effective gear ratio(lower the pulling power), like Joey said the Alabama Clay is like peanut butter crossed with quicksand, it draws you in then doesn't want to let go because of its composition. So the mud is effectively stuck to the vehicle holding it in place so you have to break the mud apart or break the vehicle free( consider a 3'x3'x3' section of dry earth weighs @2700-3000lbs) so if you're pushing a portion of that do the math for dirt on dirt CoF. Then add that to the vehicle then account for accessories and a slight incline or a root or rock, or you may have to position the block in such a way that you are in effect lifting AND pulling the vehicle free to get it over the obstacle.
Twice the weight of a vehicle is a general guideline, I like triple the weight and a snatch block, just in case.
Better to have it and not need it than need it and not have it.
