Ship may have to wait for days before finding a time when incoming waves and tidal currents are right, permitting them to enter the harbor with safety.
船只必须等待多日才能等到合适的波和潮流，从而使得它们能安全地进港。
2
An artificially enclosed area of a river or harbor designed so that the water level remains unaffected by tidal changes.
内港，内湾：留作河流或港口专用的人工围起的区域，潮水变化不致使水位受影响。
3
Zhanjiang Harbor is the largest tidal inlet along South China coasts and the largest ebb-tidal delta developed in the inlet entrance area.