Circle the best answer for each system which matches the illustrations at the right.
Information: All winches have a maximum capacity of 2 tons. All single sheave rigging blocks are rated at 3 ton WLL, and triple sheave rigging blocks are rated at 10 ton WLL. All load and wall anchor pulling lugs are rated at 8 ton WLL each. All shackles are rated at 12 tons each.
Panels from ITI Bookstore‘s Journeyman Rigger’s Reference Card and Master Rigger’s Reference Card have been provided to assist you in your calculations.
(Answers below)
System 1, no blocks
A) OK
B) No, high potential for overload if the winches are not synchronized
System 2, single sheave blocks
A) OK
B) No, it would not tend to pull square and would require constant attention to rollers
System 3, triple sheave blocks
A) OK
B) No, it would overload the load’s pulling lug
Caution: Don’t stand in the bight.
Happy trails to all my crane and rigging friends,
Mike Parnell
ITI-Field Services
P.S. This article was originally published in The Pro Rigger– Rigging Selection (sheave blocks)
Answers:
System 1 = B, System 2 = B, System 3 = A
