單項選擇題

What is the purpose of the equalizing beam aboard a crane vessel（）.

A.It allows for rotation of the hook in the single mode
B.It is required to“twin-up”30-ton pedestal cranes
C.It is used to pick up light loads
D.It is used to rigidly connect two cranes

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單項選擇題

What is meant by the term“l(fā)uffing the boom”of a crane（）．

A.Stopping the boom
B.Topping or lowering the boom
C.Moving the boom left or right
D.All of the above

單項選擇題

What does “evel-luffing” accomplish during crane operations（）.

A.It prevents the load from swinging when the boom level is adjusted
B.Less power is needed when topping the boom with a load on the hook
C.It maintains the height of the load above the deck
D.All of the above