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It is important for you to understand, the factors and basis of selecting key ship’s machinery, including main Propulsion Plant including the steering, Power requirements, Refrigeration and Air Conditioning Systems etc. The conventional systems are changing quite fast due to the changes in Technology and new developments.
Now-a-days, the usage of high voltage electrical systems in ships has been in an increasing state. It is very important to know the hazards and dangers of using these HV systems. So, it is necessary to provide training on the safety procedures to the personnel who are working under these HV systems. Underestimation of the hazards of HV systems and employing untrained personnel could definitely bring in more risk.
The Gas turbine operates on LNG boil off gas, runs a generator and then uses the exhaust gas to heat the boiler, wherein the additional boil off gas can be used to fire the boiler also, the steam thus generated runs a steam turbine which drives a generator, both the generators, run a motor to drive the conventional propeller as shown below. Additionally a LNG operated diesel engine can also be used as a generator.
Quick acting and sensitive tripping actions are also provided. Closing coil being operated by a push button is available to close the circuit breaker electrically. An interlock contact can be provided in the control circuit to prevent alternator circuit breaker from closing when shore supply breaker is in closed condition. No volt coil or under voltage release coil is provided to trip the circuit breaker when a voltage dip (around 50 to 60%) occurs. It also prevents circuit breaker from being closed when generator voltage is very low or absent. A push button switch for opening the circuit breaker by dropping the no volt coil is available. A contactor is used for dropping the coil and trip the circuit breaker by protection relays and interlocks.
Low-speed two-stroke large bore diesel engines were developed over a few decades as the most acceptable marine main propulsion engine for all major, deep sea cargo ships. They were preferred to steam engine or turbine because of their low fuel consumption and a simpler engine unit that does not depend on, boiler. Their other advantages were soon established as a power generator with less number of cylinders and a smaller space for the engine room as compared to any other engine system including four stroke diesel engines. In quest for more power, an increase of diameter of cylinder bore was a significant parameter which proportionately gave more power for a small increase. Large bore and long stroke engines were developed but with limitations of different types in each case. Ln early two stroke diesel engines, port scavenged and port exhausted engines proved attractive for their simplicity, low initial cost and cost of maintenance. The angles between successive cranks were closer and that made the engine distinctly advantages for quick starting and reversing. The main engine shaft could be extended through a thrust block right up to the end of the ship to connect a propeller directly. The type of engine was adopted to any ship as a main propulsion engine, turning a single propeller at the aft end of the hull.
New technologies with respect to cleaner energy sources are being developed and introduced very rapidly, but it will still take some time before some of these innovations become standardized equipment on ships. However, by using the developments in the Technology field, the existing designs and machinery can be further improved to decrease fuel consumption and thus minimize the emissions of ships by improving the hull shape, propeller, rudder and the interaction between all of them or fit some hydrodynamic and propulsion “boost” appendages to improve the ship’s overall fuel efficiency.