GTU 3170623 Port and Harbour Engineering Summer 2026 Solved Paper & Solutions

Advantages of water transportation:

1. Cheapest mode for bulk and heavy cargo over long distances (coal, ore, oil, containers).
2. Large carrying capacity: one ship carries thousands of tonnes.
3. Natural route: the sea needs no track or road building; only ports are needed.
4. Low energy use and pollution per tonne-km.
5. Carries most international trade.

Disadvantages:

1. Slow compared with road, rail and air.
2. Depends on weather, waves, tides and season.
3. Limited to places near the sea, rivers or canals; needs other modes for the final journey.
4. High cost of ports, dredging and maintenance; risk of accidents and piracy.

1. Wharf: a berthing structure built parallel to the shoreline, along which ships lie to load and unload cargo. It is usually a solid or open structure backed by land.
2. Jetty: a narrow berthing structure built projecting into the sea, at right angles (or at an angle) to the shore, connecting the shore to deep water, so ships can berth without dredging up to the shore.
3. Breakwater: a protective barrier (wall or mound of rubble or concrete) built in the sea to protect the harbour area from waves, so that ships can lie in calm water.
4. Dolphins: isolated marine structures (groups of piles or cellular structures) placed in the water near a berth, used for mooring and berthing ships, guiding them, and reducing the length of a pier or wharf. Types: breasting dolphins (take the berthing impact) and mooring dolphins (hold the mooring ropes).

A harbour is a sheltered area of water where ships can anchor safely and load or unload cargo and passengers. A typical artificial harbour layout is shown below.

Schematic layout

Components

1. Breakwaters: walls or rubble mounds that protect the harbour from waves and give calm water inside.
2. Entrance: the opening between the breakwaters through which ships enter; wide enough for safe navigation but narrow enough to limit waves.
3. Approach channel: a dredged, marked channel of sufficient depth and width leading ships from the sea to the berths.
4. Turning basin: an area large enough (diameter about 1.5 to 2 times the ship length) for ships to turn around.
5. Anchorage (harbour basin): sheltered water where ships wait or lie at anchor.
6. Wharves and quays: berthing structures parallel to the shore for loading and unloading.
7. Piers and jetties: berthing structures projecting into the water.
8. Docks: dry docks for repair of ships, and wet docks where water level is kept constant behind lock gates in places of high tidal range.
9. Navigational aids: lighthouse, buoys and beacons to guide ships safely.
10. Transit sheds: near the berths for short-term storage of cargo while it is checked and cleared.
11. Warehouses: away from the berths for long-term storage.
12. Land transport links: railway lines, roads and pipelines connecting the port to the hinterland.
13. Other facilities: cranes and cargo handling equipment, fire fighting, water and fuel supply, customs and administrative offices, and a signal station.

Harbours are classified as follows:

1. Based on protection needed

• Natural harbour: protected by natural features such as headlands, islands or bays. Examples: Mumbai, Visakhapatnam (partly), Sydney.
• Semi-natural harbour: partly natural, partly protected by man-made works. Example: Mormugao (Goa).
• Artificial harbour: protection made entirely by breakwaters. Examples: Chennai, Paradip.

2. Based on utility

• Harbour of refuge: shelter for ships in storms. Example: Dover (UK).
• Commercial harbour: for trade and cargo. Examples: Kandla (Deendayal Port), Mundra, Kolkata.
• Fishing harbour: for fishing boats. Example: Veraval (Gujarat).
• Military (naval) harbour: for naval ships. Example: Karwar.

3. Based on location

• Ocean (sea) harbour: on the sea coast. Example: Chennai.
• River or canal harbour: on a river. Example: Kolkata on the Hooghly.
• Lake harbour: on a large lake. Example: Chicago (Lake Michigan).

After the preliminary layout of a port is fixed, and before the final design, detailed information must be collected so that each structure can be designed safely and economically. The main items are:

1. Hydrographic survey

• Detailed depths (soundings) of the sea bed over the harbour area, channel and berths.
• Contour maps of the sea bed, to fix the dredging quantity.

2. Tidal data

• Tidal range (high and low water levels), mean sea level, chart datum and extreme levels during storms.
• Needed to fix the levels of wharves, depth of channels, and the need for lock gates or wet docks.

3. Wave data

• Height, period, length and direction of waves, including the maximum design wave in storms (cyclones).
• Needed to design breakwaters and to check calm conditions inside the harbour.

4. Currents

• Speed and direction of tidal and ocean currents, which affect ship handling and sediment movement.

5. Wind data

• Speed, direction and frequency of winds (wind rose), and cyclone history. Wind generates waves and affects berthing.

6. Littoral drift and sediment data

• Rate and direction of sand movement along the coast, which can cause siltation of the channel and erosion of nearby beaches.
• Needed to plan dredging and protect the coastline.

7. Geotechnical (soil) investigation

• Boreholes at the sites of breakwaters, wharves and docks to find the type of soil and rock, bearing capacity and settlement.
• Needed to choose the type of foundations (piles, caissons, gravity walls).

8. Materials and construction resources

• Availability of rock, stone, sand and cement for breakwaters and other works, quarry locations and transport.

9. Traffic and ship data

• Expected cargo volume, types of cargo and size of ships (length, beam, draft), which fix the number and length of berths and the depth.

10. Land and environmental data

• Land for storage, roads, railways and future expansion; environmental impact, marine life and coastal regulation zone (CRZ) rules.

11. Model studies

• Hydraulic model tests of wave action, siltation and ship navigation to confirm the layout.

Water waves are formed mainly by wind blowing over the water surface.

1. Friction and pressure of the wind on the surface create small ripples (capillary waves).
2. The ripples give the wind more surface to push, so they grow into larger gravity waves.
3. The size of waves depends on wind speed, duration of the wind and fetch (the distance of open water over which the wind blows).

Waves are also generated by earthquakes and landslides (tsunamis), by the gravitational pull of the moon and sun (tides), and by moving ships.

A tidal datum is a reference level of the sea, based on the tides, from which heights and depths are measured in harbour work and on charts.

Common tidal datums:

1. Mean Sea Level (MSL): the average level of the sea over a long period (about 19 years).
2. Mean High Water Springs (MHWS) and Mean Low Water Springs (MLWS): average high and low water during spring tides.
3. Mean High Water Neaps (MHWN) and Mean Low Water Neaps (MLWN): average levels during neap tides.
4. Lowest Astronomical Tide (LAT): the lowest level predicted under normal conditions.
5. Chart Datum (CD): the level to which depths on navigation charts are referred. It is chosen low (usually near LAT or MLWS) so that the actual depth is almost always more than the charted depth, for the safety of ships.

Uses: fixing the depth of channels and berths, the level of wharves and decks, the design of breakwaters and docks, and the heights of navigation aids.

A breakwater is a protective structure built to break the force of waves and create calm water inside a harbour. Breakwaters are of three main types.

1. Mound (rubble mound) type

• A trapezoidal mound of rock: a core of small quarry stone, secondary (filter) layers, and an outer armour layer of large stones or concrete units such as tetrapods, dolosse or accropodes.
• Waves break on the sloping face and lose energy.
• Suitable for soft or poor foundations and shallow water, where rock is easily available.

2. Vertical wall type

• A vertical face of masonry, concrete blocks or concrete caissons filled with sand, standing on a rubble base.
• Waves are reflected (not broken) by the wall.
• Suitable for deep water and good foundations; the inner side can be used as a berth.

3. Composite type

• A vertical wall on top of a high rubble mound.
• Used in very deep water, where a full vertical wall or a full mound would be too costly.

Special types

• Floating breakwaters: pontoons that reduce small waves in sheltered areas.
• Pneumatic or hydraulic breakwaters: air bubbles or water jets that disturb waves (for small waves, temporary use).
• Submerged breakwaters: below water, to reduce waves on beaches.

Selection

The type is chosen considering depth of water, wave height, foundation soil, availability of materials, cost and whether the breakwater is also to be used as a berth.

A floating dock is a floating, U-shaped steel structure (pontoon with side walls) used to lift ships out of the water for repair, inspection and cleaning of the hull.

Working:

1. The ballast tanks in the pontoon and walls are filled with water, so the dock sinks low enough for the ship to float in.
2. The ship is moved in and positioned over keel and bilge blocks.
3. Water is pumped out of the tanks; the dock rises, lifting the ship clear of the water.
4. After repair, the tanks are flooded again and the ship floats out.

Advantages: can be moved to another place or sold; needs no excavation; useful where land is costly or soil is poor; can be built quickly.

Disadvantages: high maintenance (corrosion of steel), needs deep water to sink, and the lifting capacity is limited.

A wharf is a berthing structure parallel to the shoreline, where ships lie alongside to load and unload. Wharves are classified by their structure.

1. Solid (gravity) wharf

• A massive wall of concrete, masonry or blocks that resists the earth pressure of the filled land behind by its weight.
• Types: block-work wall, cellular sheet pile wall, caisson wall.
• Advantages: strong, durable, low maintenance; good for heavy cargo.
• Disadvantages: needs a firm foundation; reflects waves; costly in deep water.

2. Open (pile-supported) wharf

• A deck slab supported on piles (concrete or steel), with a sloping rubble embankment under it.
• Water can flow below the deck.
• Advantages: suitable for soft soil; less wave reflection; lighter structure; economical in deeper water.
• Disadvantages: piles may corrode; lower load capacity than solid wharves.

3. Sheet pile wharf

• A wall of steel or concrete sheet piles, driven into the ground and held back by tie rods and anchor walls (anchored bulkhead).
• Advantages: quick to construct; suitable for medium depths and soft soils.
• Disadvantages: corrosion of steel; limited height.

4. Cellular (diaphragm) wharf

• Cells of interlocking steel sheet piles, filled with sand or gravel, act as gravity units.
• Used in deep water and where rock is near the surface.

5. Crib wharf

• Timber or concrete cribs (boxes) filled with stone; an older type used in small harbours.

Selection

The type depends on the depth of water, soil conditions, loads, materials available, wave conditions and cost.

A lighthouse is a tall tower with a powerful light at the top, built on the coast, on islands or on rocks, to guide ships at night and in poor visibility.

Functions:

1. Warns ships of dangers such as rocks, reefs and shallow waters.
2. Marks the entrance to harbours and helps ships fix their position.
3. Gives a landfall mark for ships approaching the coast.

Main features:

• Light: a strong lamp (now LED) with a Fresnel lens to concentrate the beam; visible over long distances (often 20 to 30 nautical miles).
• Characteristic: each lighthouse has its own pattern of flashes (fixed, flashing, occulting) and colour, so ships can identify it from the chart.
• Tower: height chosen for the required range, since the Earth's curvature limits visibility; painted in distinctive colours for day identification.
• Often fitted with fog signals (horns) and radar beacons (RACON).

Example: the lighthouses at Dwarka and Veraval on the Gujarat coast. Today GPS supports navigation, but lighthouses remain important backups.

Floating navigational aids are anchored in the water to guide ships safely through channels and around dangers, especially where fixed structures cannot be built.

1. Buoys

Buoys are floating bodies (steel or plastic) anchored to the sea bed by chains and sinkers. They carry shapes, colours, numbers and often lights, bells, whistles or radar reflectors.

Shapes: can (cylindrical), conical (nun), spherical, pillar and spar buoys.

IALA buoyage system (International Association of Lighthouse Authorities; India follows Region A):

Mooring buoys: large buoys to which ships tie up, without needing a berth.

2. Lightships (light vessels)

• Ships anchored at a fixed position, carrying a strong light, fog signals and radio beacons.
• Used where a lighthouse cannot be built, such as at the approach to a port over soft, deep sea bed or at shifting sand banks.
• Now mostly replaced by large automatic navigational buoys (LANBY) because manned lightships are costly.

3. Light floats

• Small unmanned floats carrying a light; used in sheltered waters, rivers and estuaries.

4. Other floating aids

• Radar reflectors and RACONs on buoys, which show up on ships' radar.
• AIS (Automatic Identification System) buoys that transmit their position electronically.

Requirements

Floating aids must be clearly visible, easily identified (shape, colour, light pattern), reliable, kept in their correct position, and regularly maintained, since chains wear and buoys can drift.