 Hello everyone. Myself, Ms. Shailaja Diavarkonda, assistant professor in civil engineering department, Vulture Institute of Technology, Solapur. In today's lecture, we are going to study the modes of transportation, docks and harbors. These are nothing but the water transportations. At the end of this video, the viewers will able to explain importance of docks and harbors and its classification. First we have to see what are the importance of water transport. Water transport is the cheapest and the oldest mode of the transport. In earlier days, water transport is mostly used for the transporting for maximum distances. The cost of operation of water transport is also very low, means the construction cost as well as the maintenance cost of the water transportation system is low. It has the largest carrying capacity and it's most suitable for carrying bulky loads over the long distances. It operates on a natural track and hence does not require huge capital investment in the construction and maintenance. So by water transport, we can transfer the bulky loads over the long distances. So it is the typical view of the water transport. Introduction to docks. So in this figure, you can see the typical view of the dock. Docks are enclosed areas for berthing the ships to keep them afloat at a uniform level to facilitate loading and unloading of cargo. It is the structure made for berthing of vessels for loading and unloading cargo and passengers. So normally in docks, we manufacture the ships and keep the ships at a uniform floating level. Then these docks are classified as wet dog and dry dock. Dry dock. In this figure, you can see the typical view of dry dock. In dry dock, we are manufacturing or repairing the ships. It is a long excavated chamber having side walls, a semi-circular end wall and a floor. Means at this area, you can manufacture the new ships or you can repair the ships if any problem is there. So it is constructed near the water surface where harbours are there. The open end of the chamber is provided with a gate and act as an entrance to the dock. This figure shows the typical view of the wet dock. These are also used or these are also required for berthing of ships or vessels to facilitate the loading and unloading of passengers and cargo are called as wet dock. These are also known as harbour docks. Introduction to harbour. Harbour is a shelter water body where ships, boats and bargages can be docked. Means it is nothing but the parking area which is constructed for the ships, boats etc. It is a manmade facility built for loading and unloading vessels and dropping and picking up the passengers. Harbour may be a natural or artificial. So you can see in this figure, it is nothing but the parking area for the ships, boats for loading and unloading of the cargo and passengers. Docks are the areas where the ships are manufactured and harbour is the area where those are parked for the loading and loading of cargo. In this figure, we can see the various parts of the harbour. Entrance channel, breakwater, jetties, anchorage area, turning basin and port facilities. Entrance channel is the entrance provided for the ships and boats to enter in the harbour. The depth and width of entrance channel kept maximum and it is decided by the traffic on this entrance channel. Birthing basin and turning basin. This birthing basin or turning basins are provided for manufacturing of the ships and for turning of the ships. Here it is breakwater. You can see this line is indicated as the breakwater. This structure is constructed with stones or rubbles to avoid or to protect from the sea waves. Peer head. Peer head is a structure constructed at the top of the breakwater. So those are nothing but the lighthouses such as. Jetties and varwits. These jetties and varwits are provided at the ends of the entrance channel. Again these harbours are classified as natural harbour, semi-natural harbour and artificial harbour. Natural harbours. In this figure you can see the typical view of the natural harbour. It means if you see this structure it is naturally constructed. Means it is naturally present and it created a basin for the loading and unloading of the ships and boats. It is a protected form storms and waves. It is prominence of land. It consists of part of body of water which is protected and the deep enough for the anchorage. So semi-natural harbour. In semi-natural harbour we have to construct the structure to avoid the waves and you have to make the entrance. Means here you can see this structure. This structure is constructed to entrance of the boat and to avoid the waves from the sea. So the one who are protected on sites by land and requires man-man protection only at the entrance. So you can see here it is the entrance for this harbour and this structure is constructed. Artificial harbours. These are man-made harbours deliberately constructed breakwaters, sea walls, jetties and also dredging is done. Means these harbours are constructed by dredging the material from this area and they have prepared a channel or basin. It requires maintenance by periodic dredging means as it is artificial harbour. So by time by time we can check the depth of water for the convenience of the harbours. Now these are the advantages and disadvantages of the water transport. It means it is the advantages and disadvantages of the docks and harbours. The water transportation is possible only through the docks and harbours and ports. So it is the powerful means of transportation by the defence. It is cheapest. The overall development of the commerce industry and trades it has high loading carrying capacity and it requires chief motive power like diesel engines. The disadvantages are it requires more time due to low speed. In tight range period loading and unloading may be delayed. The fluctuations of water level produce rubbing friction effect on the side birds. Now you pause this video and try to answer this questions. These are the answers for the questions. These are the references considered for the study. Thank you.