单项选择题
A.at anchor B.being towed C.aground D.drilling
A mobile offshore drilling unit under tow is approachin...
单项选择题A mobile offshore drilling unit under tow is approaching a fog bank. When should fog signals be started? （）
A.When the towing vessel enters the fog B.When the drilling rig enters the fog C.When the towing vessel can no longer be seen from the rig D.Immediately
A mobile offshore drilling unit must display obstructio...
单项选择题A mobile offshore drilling unit must display obstruction lights when it is on the waters over the Outer Continental Shelf and is（）.
A.under tow B.fixed to the seabed C.underway D.All of the above
A message by flashing light consists of the call，the id...
单项选择题A message by flashing light consists of the call，the identity，the text，and the （）.
A.destination B.answer C.time D.ending
