This field of engineering includes the engineering of boats, ships, oil rigs, and any other marine vessel or structure. It also comprises oceanographic engineering or ocean engineering. Specifically, it is the discipline of applying engineering sciences, including mechanical engineering, electrical engineering, electronic engineering, and computer science, to the development, design, operation, and maintenance of watercraft propulsion, onboard systems, and oceanographic technology. Marine engineering includes but is not limited to power and propulsion plants, machinery, piping, automation and control systems for marine vehicles of any kind, such as surface ships and submarines.

Specialties of Marine Engineering

Naval architecture sector: Naval architects are concerned with the overall design of the ship and its propulsion through the water.

Mechanical engineers: These engineers design the main propulsion plant, the powering and mechanization aspects of the ship functions like steering, anchoring, cargo handling, heating, ventilation, air conditioning interior and exterior communication, and various other related needs their supplier's design electrical power generation and electrical power distribution systems. The only installation is the design responsibility of the marine engineer.

Oceanographic engineering: This stream of engineering basically is concerned with mechanical, electrical, electronic, and computing technology which is deployed to support oceanography. It also falls under the umbrella of marine engineering, especially in Britain, where it is covered by the same professional organization, the IMarEST.

Offshore engineering: Civil engineering for an offshore environment, the design, and construction of fixed and floating marine structures, such as oil platforms and offshore wind farms are generally called offshore engineering.

Challenges faced by marine engineers  

Hydrodynamic loading: Maritime engineers design to accommodate a ship being flexed or a platform being struck by waves millions of times in its life just like civil engineers design to accommodate wind loads on building and bridges.

Stability: A naval architect is concerned with stability. The job of a naval architect is different, insofar as a ship operates in two fluids simultaneously: air and water. Engineers to come across the challenge of balancing cargo as the mass of the ship rises and the center of gravity shifts higher as additional containers are stacked vertically. The weight of fuel, in addition to this, presents a problem like the pitch of the ship-source the weight to shift with the liquid causing an imbalance. 

Corrosion: Ships and offshore structures face the harshest chemical environment than nearly anywhere on land. Marine engineers work with surface protection and preventing galvanic corrosion in every project. Corrosion can be reserved through cathodic protection by the utilization of pieces of metal known as sacrificial anodes. Zinc is a piece of metal which is applicable as the sacrificial anode as it becomes the anode in the chemical reaction. This process causes the metal corrosion and not the hull of the ship. 

Anti-fouling: The process of eliminating obstructive organisms from essential components of seawater systems is called Anti-fouling. Marine organisms grow and attach to the surfaces of the outboard suction inlets which are used for obtaining water for cooling systems. Electro-chlorination involves running a high electrical current through seawater. The combination of current and seawater alters the chemical composition to create sodium hypochlorite to purge any bio-matter.

Emission of Sulfur: The burning of marine fuels has the potential to release harmful pollutants into the atmosphere. Marine diesel is burnt by ships in addition to the heavy fuel oil. Heavy fuel oil is the heaviest of all the refined oils and it releases sulfur dioxide when burned. Emissions of sulfur dioxide have the potential for rising atmospheric and ocean acidity causing harm to. It is commercially advantageous because of the cost-effectiveness which is compared to other marine fuels. The heavy fuel oil may only be burned in international waters because of the pollution created. It prospects that heavy fuel oil will be phased out of commercial use by the year 2020.

Oil and water discharge: Oil, water, and other substances collect at the bottom of the ship in which is called as the bilge. Bilgewater is pumped overboard but must pass a pollution threshold test of 15 ppm (parts per million) of oil to be discharged. The tank is sent back to the oily water separator and utilizes gravity for the separation of the fluids due to their viscosity. Water is carried out and either discharged if clean to a holding tank to be separated before being tested again. Ships over 400 gross tons are needed for carrying the devices to separate oil from bilge water. Further, as enforced by MARPOL, all ships over 400 gross tons and all oil tankers over 150 gross tons are required to log all oil transfer is an oil record book (EPA, 2011).

Cavitation: Cavitation is the process of forming an air bubble in a liquid due to the vaporization of that liquid caused by an area of low pressure. Cavitation can take place in pumps, which can cause damage to the impeller that moves the fluids through the system. This low-pressure area lowers the boiling point of a fluid which allows it to vaporize into a gas. Cavitation can also be seen in the process of propulsion. Pockets with low pressure formed on the surface of the propeller blades as its revolutions per minute increase (IIMS, 2015). Cavitation on the propeller sourced a small put violent implosion which could have wrapped the propeller blade. To solve this issue, more blades allow the same amount of propulsion force but at a lower rate of revolutions. This is very crucial for submarines as the propeller requires keeping the vessel relatively quiet to stay hidden. The vessel with more propeller blades is able for achieving a similar amount of propulsion force at lower shaft revolutions.

Interesting Facts about Marine Engineering

No one has heard about a marine engineer about a century ago, but today it is a profession which is as established as any other famous ones. Not only this, but it has also branched out into various specialized fields that have achieved great progress. Most of these new fields are aligned with any of the basic engineering branches like mechanical, electrical, civil, electronics, computers etc. and have something or the other incorporated from them. One such branch is called marine engineering.

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By: Preeti Narula