How do harbors shelter ships from wind waves and currents?

Harbors shelter ships from wind, waves, and currents primarily through the use of artificial structures known as breakwaters or jetties, which are designed to provide calm water inshore.12

• Breakwaters: These are artificial offshore structures that intercept waves and longshore currents. By enclosing an area of water, they create a sheltered basin where ships can safely anchor or load and discharge cargo. Engineers often use hydraulic models to test the placement of these structures to ensure they effectively minimize wave energy and prevent undesirable disturbances within the harbor.3124
• Jetties: These structures are often built at the entrances to harbors, rivers, or locks. They serve to "train" or confine currents to maintain navigable channels and protect the entrance from the disruptive effects of littoral currents, sand drift, and wave action. When constructed of solid materials, they can also function as breakwaters.5
• Natural Shelter: Where the construction of massive breakwaters is economically prohibitive, engineers seek out natural harbors, such as bays, estuaries, or sheltered creeks, which inherently provide protection from adverse weather.16