A quay is a solid berthing structure built along and generally integrated with the shoreline — vessels moor alongside it directly, parallel to the shore, rather than approaching a structure projecting outward into the water.
Quay vs Jetty: The Structural Difference
- Quay — solid, runs parallel to shore, typically backfilled and integrated with the land itself
- Jetty — projects outward from shore, often pile-supported, allowing water to flow beneath and around it
This structural difference has real practical consequences during berthing — a solid quay presents a consistent wall-like structure, while current and surge effects around a pile-supported jetty can behave differently, given the water flowing beneath and around the structure.
Quay vs Wharf
“Quay” and “wharf” are often used interchangeably in practice, both describing a solid berthing structure along the shore — regional and local terminology conventions vary, and confirming the actual physical layout of a specific berth matters more than the exact word used to describe it.
Quay Construction
Modern quays are typically reinforced concrete or steel sheet-pile construction, engineered to withstand both the static weight of cargo-handling equipment (gantry cranes, storage) and the dynamic forces of vessels berthing alongside — a genuine, significant engineering undertaking, not simply a paved edge to the water.
Quay Fendering and Bollards
Quays are fitted with fendering (absorbing berthing impact) and bollards (for securing mooring lines) at intervals along their length, sized and positioned according to the vessel types expected to use that specific quay.
Water Depth Alongside
A quay’s usable depth alongside — how deep the water is directly against the structure — determines which vessel drafts it can accommodate, a genuine factor in berth assignment that must match a specific vessel’s actual draft with adequate under-keel clearance.
Exam Relevance
Quay construction, its distinction from jetty structures, and berthing considerations are covered within Ship Knowledge and Port Operations topics in deck officer competency exams.