05-07-2014, 11:26 AM
Harbour Engineering
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Ocean Water Transport
It is an important component of national security in case of an emergency situation.
It is cheaper than railways and roadways since it does not involve laying of special tracks or surfaces.
It improves national and international trade, hence improving the economy.
It has high load carrying capacity.
It allows people of a particular country to gain access to foreign goods such as medicines, machinery etc.
It requires cheap motive power
It has brought prosperity to countries like UK, USA etc.
Types of Harbour
Depending on protection needed :-
Natural Harbour
Semi Natural Harbour
Artificial Harbour
Natural Harbours are those natural features which allow for safe accommodation of ships on sea coasts such as creeks and basins. However modern day ships are huge in size and hence require improvements. Natural Harbours usually have development around them and hence attract more trade. Eg. Mumbai
Classification Of Harbour based on utility
Harbour of refuge :- Ready accessibility from the high seas, arrangements for repair and supplies.
Commercial Harbour :- Harbour for trade of mercantile items, adequate space for loading and unloading of cargo along with facilities for their storage.
Fishery Harbour :- Harbour for arrival and departure of fishing ships. Quick loading and unloading is required due to perishable nature of fishes and refrigerated storage for preserving catch.
Military Harbour :- Military bases to accommodate military ships. They also serve as supply depots.
Marina Harbour :- Marinas provide shelter, toilets, fuel, food etc. for temporary or permanent residence of small ship owners. Provide service, shelter and dockage to smaller leisure ships.
Classification of Marinas
Large Marinas :- Usually cater for over 200 boats. Long waiting list for access.
Small Marinas :- Usually cater for 100 boats or less. In fresh water or coastal waters.
Site Selection Criteria
Availability of cheap land and materials.
Easy transport and communication.
Natural protection from winds and waves.
Industrial development around the region.
Traffic potential around the harbour.
Availability of electricity and clean water.
Defence and strategic aspects.
Harbour Depth
When bottom is soft,
Maximum harbour depth= Loaded draft +1.2m
When bottom is rock,
Maximum harbour depth= Loaded draft + 1.8m
Dock Entrances
Ships can enter docks either directly or through gates.
Types of gates :-
Wooden or iron gates:-
Wooden entrances require only one gate rather than two.
They however restrict the incoming ship’s entrance to periods during high tides.
Caissons:-
Sliding caissons :- Box shaped steel structures with proper internal bracing. Caissons can either be moved on rollers and rail. The caissons can also serve as a bridge across the dock entrance.