单项选择题
When（）clean ballast water from any vessel，an application shall be made to Harbor Authorities for approval.
A.discharging B.recircling C.loading D.taking in
单项选择题 What would be prima facie evidence of unseaworthiness? （）
单项选择题 What is the purpose of pressure-vacuum relief valves? （）
单项选择题 What is the principle behind dynamic braking as used on an anchor windlass?（）
