The boom indicator tells the operator at what angle the boom

The boom stops are installed on an offshore crane to ______.

A.prevent the boom from being raised too high

B.prevent the boom from swinging

C.support the boom when not in use

D.prevent the boom from being lowered

With a given load on the cargo hook，the thrust on a cargo boom ______.

A.increases as the angle to the horizontal increases

B.increases as the angle to the horizontal decreases

C.is greatest at an angle of 45° and decreases as the boom is raised or lowered

D.is least at an angle of 45° and increases as the boom is raised or lowered

On a crane, the boom indicator tells the operator what angle the boom angle is compared to the ______.

A.vertical position

B.horizontal position

C.boom stop angle

D.minimum radius angle

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

The boom indicator on a crane will indicate the ______．

A.Length of the boom

B.Angle of the boom

C.Lifting capacity of the boom

D.Direction of the boom

With a given load on the cargo hook，tension in a single span topping lift ______.

A.increases as the boom's angle to the horizontal increases

B.is at a maximum when the boom is at a 45° angle to the horizontal

C.increases as the boom's angle to the horizontal decreases

D.decreases as the boom's angle to the horizontal decreases

The signal man assisting a crane operator has his arm extended with his fingers closed and thumb pointing upward．This is the signal to ______．

A.raise the boom

B.raise the hook

C.raise the boom and hook

D.check the boom stop

What cargo does a jumbo boom or heavy derrick used for lifting?

The load chart of a ship crane enables the operator to combine the load radius with boom length to determine the ______．

A.Maximum counter weight required

B.Minimum horsepower required

C.Hoist rope strength

D.Allowable load

What is meant by the term“luffing 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