Common Types Of Sling Configs, Working Load Limits And Their Applications

Question 1

What are 3 common slings and their rated WLL

Answer 1

Vertical hitches- when used in straight pulling fashion, the single vertical hitch will safely hoist 100% of its rated WLL

Choker hitch- when used in a straight pulling fashion, the choker hitch will safely hoist 75% of its WLL

Basket hitch- When the legs of the basket hitch are in the vertical position, the basket hitch will safely hoist 200% of its rated WLL

Question 2

Bridle hitch

Answer 2

Used on loads that have suitable attachment points. Usually have 2, 3 or more legs to form the bridle hitch. When it has more than 2 legs you cannot assume all the legs are sharing the load equally. Regardless of the total number of legs, the load might be shared by only 2 legs. While the other 2 are used for balancing (bridle hitch with 4 legs).

Question 3

Basket hitch

Answer 3

Passed through the load, with both ends of the slings attached to the main hook. When the legs of the basket hitch are in the vertical position, the basket hitch will hoist 200% of its rated WLL. Never use a single basket hitch on loads that could tilt or slide.

Question 4

Double basket hitch

Answer 4

This is used when a load requires support from underneath. The double basket hitch has to be located so that the load is balanced between the 2 points of support. The legs have to be at an angle of 60° from the horizontal to prevent the legs from sliding towards each other.

Question 5

Double-wrap basket hitch

Answer 5

Wrap the sling completely around the load. This double wrapping compresses all components of the load together so that even the top pieces will not slip out of the rigging.

Question 6

Double chokers and double wrapped choker hitches

Answer 6

Double choker hitches must be used on all horizontal loads that contain 2 or more pieces of materials that are over 3m (10ft.) In length.

Double wrap choker hitches are similar to double wrap basket hitches and can be used singly or in pairs

Question 7

Endless slings

Answer 7

Also called “grommet slings” are usually made of fibre rope or synthetic webbing. They are light to handle and do not damage loads, but because they’re subjected to sharp bends, they tend to deteriorate more rapidly than most other types of slings.

Question 8

What is the formula to calculate a slings WLL?

Answer 8

Bridle hitch:
WLL= WLL of a single bridle hitch× H× number of legs÷ L

Basket hitch:
WLL= WLL of single vertical hitch×2
(If the legs are inclined the WLL will be reduced)
WLL= WLL of SVH×H÷L×2

Double basket hitch-
WLL=WLL of SVH×H÷L×4

Single choker hitch-
WLL= WLL of SVH×3/4
If its below a 45° angle you use this formula
WLL= WLL×A÷B×H÷L×2

A=Height from material to hooked
B=Length from hook to edge of material
2= this is a formula for a pair of single choker hitches