How do breakwaters create calm water for an artificial harbor?

Breakwaters create calm water for an artificial harbor by intercepting and dissipating the energy of incoming sea waves. These structures are designed to protect harbor basins from the force of waves and severe gales.123

The mechanism of protection generally follows one of two philosophies:

• Absorption: Many breakwaters are designed to absorb wave energy. For example, structures built with specialized concrete armor units, such as tetrapods, utilize the interstices (gaps) between the units to absorb the energy of breaking waves.4
• Reflection: Vertical breakwaters, often constructed of solid concrete or masonry, function by reflecting waves back toward the sea rather than absorbing them.5

In addition to these methods, some experimental designs, such as floating breakwaters, attempt to create a sheltered area by forcing waves to expend their energy against a horizontal platform or by mimicking the calm water found in the lee of a large ship. By effectively reducing wave energy, these structures ensure that the water within the harbor remains sufficiently calm for maritime operations.612