Last reviewed 30 Sept 2026 · 8 min read
Basic terms
- Harbour — a sheltered water area where ships can anchor, load and unload, or take shelter from storms and waves.
- Port — a harbour plus the facilities on land: quays, cargo-handling equipment, storage areas, railway and road connections, and administration. A port is the link between sea transport and land transport.
- Port planning — the selection of the site and the layout of the water area, berths, storage and connections to suit the expected ships and cargo for the design life (50 years or more for the main structures).
Classification of harbours
By protection
| Type | Description | Examples |
|---|---|---|
| Natural harbour | Formed by nature: a bay, creek, estuary or river mouth with natural protection from waves and winds | Mumbai, Visakhapatnam (partly), Kochi |
| Semi-natural harbour | Partly protected by nature; the remaining opening is protected by breakwaters or similar works | Visakhapatnam, Chennai (earlier) |
| Artificial harbour | An open coast; protection is created entirely by breakwaters and dredging | Chennai, Paradip, Mangalore (New) |
By function
- Commercial harbours — carry general cargo, bulk cargo, containers, liquid cargo and passengers.
- Fishing harbours — landing and handling of fish; auction halls, ice plants, repair yards.
- Refuge harbours — provide shelter for vessels in bad weather along long stretches of coast; usually sited at the mouth of a large bay.
- Naval (military) harbours — for warships, with dockyards and repair facilities.
- Ports of call, transhipment ports, entrepôt and inland ports — with special roles in trade.
- Marinas and yacht harbours — for recreation.
By location
Sea ports (coastal), estuary or river ports (Kolkata on the Hooghly), canal ports, and inland (lake) ports. Dock harbours use gated enclosed basins to keep the water level constant against the tide (Kolkata, Mumbai).
Selection of a site
The choice of site is one of the most important decisions. The main factors:
FormulaSite-selection factors
- Natural protection and depth — a location that is sheltered from the waves; sufficient natural depth near the coast reduces dredging.
- Approach and the hinterland — good rail, road and inland waterway connections to the areas producing and consuming cargo; adequate land for storage and industry.
- Traffic potential — volume and nature of the expected cargo.
- Sediment and siltation — littoral drift, river silt and the resulting maintenance dredging; sites near river mouths with large sediment loads are disadvantaged.
- Meteorology — winds, waves, tides, currents, fog, cyclones, visibility; the percentage of days on which the port is workable.
- Geology and foundation conditions — for quays, breakwaters and reclamation.
- Navigation — a straight, safe, deep approach channel and enough manoeuvring space.
- Availability of land, water, power and labour; environmental impact and CRZ (Coastal Regulation Zone) clearance.
- Economics — the total cost of construction, operation and dredging against the benefit.
Components of a port
| Component | Function |
|---|---|
| Approach (entrance) channel | Dredged channel connecting the sea to the harbour; width and depth set by the ship size and the sea conditions |
| Harbour entrance | Opening in the breakwater, wide enough to allow safe entry and narrow enough to limit wave penetration |
| Outer harbour / anchorage | Sheltered area where ships wait for a berth or where they anchor and are worked by lighters |
| Turning basin (turning circle) | Circular or elliptical area where ships turn around; diameter 1.5 to 2 times the length of the largest ship (about 1.2 times with tug assistance) |
| Berths | Places along the quay, jetty or dolphin at which ships are moored to load or unload |
| Breakwaters | Structures protecting the harbour from waves |
| Quays, wharves, jetties, dolphins and fenders | Berthing structures (see the quays note) |
| Transit sheds, warehouses and open storage | Temporary storage of cargo between ship and land transport |
| Backup area | Land for storage, marshalling of containers, industry and logistics |
| Cargo-handling equipment | Cranes, conveyors, pipelines, loaders and unloaders |
| Road and rail connections; port control | Access and administration |
| Navigational aids and pilotage; tugs | Safe entry and manoeuvring |
Ship characteristics
The size of the ships governs every dimension of a port. Terms:
- Length overall (LOA), beam (B), draught (T) — the depth of the ship below the water, light (empty) and loaded.
- Displacement — the weight of water displaced by the ship; deadweight tonnage (DWT) — the carrying capacity in tonnes (cargo, fuel, stores); gross tonnage (GT) — a measure of the enclosed volume.
- Air draught — the height above the water (for bridges and cranes).
Approximate size classes:
| Class | Typical DWT | Note |
|---|---|---|
| Handysize / Handymax | 10,000–60,000 | General cargo and small bulk carriers |
| Panamax | 60,000–80,000 | Largest ships to pass the older Panama locks (beam about 32 m) |
| Capesize | > 100,000 | Too large for the Suez Canal when fully loaded (older definition); iron ore and coal |
| VLCC / ULCC | 200,000–320,000 / > 320,000 | Tankers |
| Container ships | Rated in TEU (twenty-foot equivalent units): feeder, Panamax, post-Panamax, ULCV (over 20,000 TEU) |