A tackle by which the outer end of a boom is raised and lowe

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

Which fitting is used to connect the boom to the mast?

A.Clevis pin

B.Gunter-lug

C.Gooseneck

D.Transom

A band or collar on the top end of a boom to which the topping lift，midships guy，and outboard guys are secured，is called the ______.

A.collar band

B.guy band

C.pad eye collar

D.spider band

Which part provides for transverse control and positioning of a boom in a conventional yard and stay system ________．

A.Guy

B.Shroud

C.Spider

D.Topping lift

In a married falls rig at the after end of a hatch，a boom is rigged in a fore and aft line through its heel．Stresses on the outboard guy will be LEAST if the guy is made fast at a point ______．

A.Abreast the heel

B.At right angles to the boom when viewed from above

C.Aft of the heel

D.Forward of the spiderband

The boom stops on a pedestal crane prevent the boom from ______.

A.being raised too high

B.swinging at sea

C.overloading when not in use

D.being lowered too low

Which statement is FALSE regarding the operation of a crane ________．

A.The crane jib is raised and lowered by the luffing winch

B.The cargo block is raised and lowered by the hoisting winch

C.The cargo block is raised and lowered by the luffing winch

D.None of the above

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

When a cargo boom or crane is rated at varying capacities，there will be a table at the controls which relates safe working load to ______．

A.winch speed

B.boom strength

C.load radius

D.cable strength