Jetty
A Jetty is a structure that projects out from the shore into the water. In port operations a berthing jetty — often a piled and decked structure — lets ships lie alongside in deeper water away from the shoreline, commonly used for tankers, gas carriers and bulk terminals served by pipelines or conveyors.
The word also describes a protective jetty or breakwater that shelters a harbour entrance or river mouth from waves and controls silting. A berthing jetty is typically fitted with mooring dolphins, fenders and a connecting trestle to shore.
Jetties open up berths where the natural water is too deep or the seabed too soft for a solid quay — which is exactly the case for the large tankers and gas carriers that cannot come close inshore. They let a terminal handle deep-draught ships without dredging an entire basin.
What is the difference between a jetty and a pier?
Both project from the shore into the water. The terms overlap; jetty is more often used for cargo, tanker and gas berths and for shore-protection structures, while pier is common for passenger and general-purpose structures.