单项选择题
A.only when the load is taken off the cable B.only when there is a load on the cable C.only when activated by the controls at the lowering station D.at any time
An effective braking system for windlasses on rigs in d...
单项选择题An effective braking system for windlasses on rigs in deep water is a(n)（）.
A.larger chain stopper B.disc backstopping brake C.hydraulic clutch D.electrical regenerative braking system
A wooden plug fitted tightly in the vent of a damaged t...
单项选择题A wooden plug fitted tightly in the vent of a damaged tank may prevent the tank from（）.
A.filling completely B.developing free surface C.developing free surface moment D.collapsing
A tackle is two blocked when the blocks are（）.A.equally...
单项选择题A tackle is two blocked when the blocks are（）.
A.equally sharing the load B.jammed together C.as far apart as possible D.rove to the highest mechanical advantage
