Center of Gravity and Sling Loading
When lifting vertically, the load will be shared equally if the center of gravity is placed equally between the pick points. If the weight of the load is 10,000 lbs., then each sling will have a load of 5,000 lbs. and each shackle and eyebolt will also have a load of 5,000 lbs.
When the center of gravity is not equally spaced between the pick points, the sling and fittings will not carry an equal share of the load. The sling connected to the pick point closest to the center of gravity will carry the greatest share of the load. Sling 2 is closest to cog. It will have the greatest share of the load. Sling 2 = 10,000 X 8 / (8+2) = 8,000 lbs. Sling 1 = 10,000 X 2 / (8+2) = 2,000 lbs.
Weights and Measures
Unit weight steel = 490 lbs/ft3
Unit weight aluminum = 165 lbs/ft3
Unit weight concrete = 150 lbs/ft3
Unit weight wood = 50 lbs/ft3
Unit weight water = 62 lbs/ft3
Unit weight sand and gravel= 120 lbs/ft3
Unit weight copper = 560 lbs/ft3
Unit weight oil = 58 lbs/ft3
1 cubic ft. = 7.5 gals
1 metric ton = 1.1 U.S. tons
1 kilogram = 2.2 lbs.
1/2 inch= 12.7 mm
1 inch = 25.4 mm
Volume of cube = height x width x length
Volume of sphere =
3.14 X (diam. X diam. X diam.) / 6
Volume of cylinder =
3.14 X (diam. X diam. X length) / 4