单项选择题
Back-up wires on a towed vessel provide（）.
A.a factor of safety
B.additional strength
C.a distribution of the towing load
D.All of the above
相关考题
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单项选择题
At the instant when a string of casing being run from a ship is landed in the well head,（）.
A.the total weight in air of the casing string is removed from the ship
B.the hook load (weight of the casing string) is removed from the ship
C.the weight of the casing inside the riser is removed from the ship
D.the weight of the casing string added to the weight of the fill-up mud is removed from the ship -
单项选择题
Anchor shackles should have a breaking strength that is（）.
A.equal to the chains they are connecting
B.25% more than the chains they are connecting
C.50% more than the chains they are connecting
D.100% more than the chains they are connecting -
单项选择题
An anchor winch should be equipped with mechanical brakes capable of holding（）.
A.half the breaking strength of the mooring line
B.the full breaking strength of the mooring line
C.the maximum expected tension of the mooring line
D.50% over the working tension of the mooring line
