Rigging With Lifting Blocks
1. Total Load
Total Load:
Load Wt. (1000 lbs.)
+ Winch Pull (1000 lbs.)
= 2000 lbs. minimum
2. One Part of Line
No Mechanical Advantage = One
Winch Pull = 1,000 lbs.
1. Total Load
Total Load:
Load Wt. (1000 lbs.)
+ Winch Pull (500 lbs.)
= 1500 lbs. minimum
2. Two Parts of Line
3. Total Load = 1,000
Mechanical Advantage = Two
Winch Pull = 500 lbs.
Pull (P) required (level ground)
= Weight (W) X Friction Factor (F)
Many surfaces have a friction factor < 1
(f) for steel on steel is .16 lubricated
(f) for steel on steel is .8 clean
(f) for wood on metal is .2 To .6 clean
(f) for wood on wood is .25 To .5 clean
Winch Pull Required =
Weight X Friction Factor
Mechanical Advantage