Marine engineering includes the engineering of boats, ships, oil rigs and any other marine vessel or structure, as well as oceanographic engineering or ocean engineering. Specifically, marine engineering 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 and on-board systems and oceanographic technology. It 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.
Archimedes is traditionally regarded as the first marine engineer, having developed a number of marine engineering systems in antiquity. Modern marine engineering dates back to the beginning of the Industrial Revolution (early 1700s).
Marine steam engineering
In 1712, Thomas Newcomen, a blacksmith, created a steam powered engine to pump water out of mines. In 1807, Robert Fulton successfully used a steam engine to propel a vessel through the water. Fulton's ship used the engine to power a small wooden paddle wheel as its marine propulsion system. The integration of a steam engine into a watercraft to create a marine steam engine was the start of the marine engineering profession.
Paddle wheel ships
Paddle steamers were the front runners of the industry for the next thirty years till the next type of propulsion came around. Only twelve years after Fulton’s Clermont had her first voyage, the Savannah marked the first sea voyage from America to Europe. Around 50 years later the steam powered paddle wheels had a peak with the creation of the Great Eastern, which was as big as one of the cargo ships of today, 700 feet in length, weighing 22,000 tons. The Great Eastern was said to be ahead of its time and was destined for failure. Since the 1800s there have been many improvements to the design of engines and propellers. The maritime industry holds 90% of all international trade.
Marine engineering specialties
Naval architects are concerned with the overall design of the ship and its propulsion through the water.
Mechanical engineers design the main propulsion plant, the powering and mechanization aspects of the ship functions such as steering, anchoring, cargo handling, heating, ventilation, air conditioning interior and exterior communication, and other related requirements. Electrical power generation and electrical power distribution systems are typically designed by their suppliers; only installation is the design responsibility of the marine engineer.
Oceanographic engineering is concerned with mechanical, electrical, and electronic, and computing technology deployed to support oceanography, and also falls under the umbrella of marine engineering, especially in Britain, where it is covered by the same professional organisation, the IMarEST.
Challenges specific to marine engineering
In the same way that civil engineers design to accommodate wind loads on building and bridges, maritime engineers design to accommodate a ship being flexed or a platform being struck by waves millions of times in its life.
A naval architect, like an airplane designer, is concerned with stability. The naval architect's job is different, insofar as a ship operates in two fluids simultaneously: water and air. Engineers also face the challenge of balancing cargo as the mass of the ship increase and the center of gravity shifts higher as additional containers are stacked vertically. In addition, the weight of fuel presents a problem as the pitch of the ship cause the weight to shift with the liquid causing an imbalance. This offset is counteracted by water inside larger ballast tanks. Engineers are faced with the task of balancing and tracking the fuel and ballast water of a ship.
The chemical environment faced by ships and offshore structures is far harsher than nearly anywhere on land, save chemical plants. Marine engineers are concerned with surface protection and preventing galvanic corrosion in every project. Corrosion can be inhibited through cathodic protection by utilizing pieces of metal known as sacrificial anodes. A piece of metal such as zinc is used as the sacrificial anode as it becomes the anode in the chemical reaction. This causes the metal to corrode and not the ship’s hull. Another way to prevent corrosion is by sending a controlled amount of low DC current to the ship’s hull to prevent the process of electro-chemical corrosion. This changes the electrical charge of the ship’s hull to prevent electro-chemical corrosion.
Anti-fouling is the process of eliminating obstructive organisms from essential components of seawater systems. Marine organisms grow and attach to the surfaces of the outboard suction inlets used to obtain water for cooling systems. Electro-chlorination involves running high electrical current through sea water. The combination of current and sea water alters the chemical composition to create sodium hypochlorite to purge any bio-matter. An electrolytic method of anti-fowling involves running electrical current through two anodes (Scardino, 2009). These anodes typically consist of copper and aluminum (or iron). The copper anode releases its ion into the water creating an environment that is too toxic for bio-matter. The second metal, aluminum, coats the inside of the pipes to help prevent corrosion. Other forms of marine growth such as mussels and algae may attach themselves to the bottom of a ship's hull. This causes the ship to have a less hydrodynamic shape since it would not be uniform and smooth around the hull. This creates the problem of less fuel efficiency as it slows down the vessel (IMO, 2018). This issue can be remedied by using special paint that prevent the growth of such organisms.
The burning of marine fuels has the potential to release harmful pollutants into the atmosphere. Ships burn marine diesel in addition to heavy fuel oil. Heavy fuel oil, being the heaviest of refined oils, releases sulfur dioxide when burned. Sulfur dioxide emissions have the potential to raise atmospheric and ocean acidity causing harm to marine life. However, heavy fuel oil may only be burned in international waters due to the pollution created. It is commercially advantageous due to the cost effectiveness compared to other marine fuels. It is prospected that heavy fuel oil will be phased out of commercial use by the year 2020 (Smith, 2018).
Oil and water discharge
Water, oil, and other substances collect at the bottom of the ship in what is known as the bilge. Bilge water is pumped overboard, but must pass a pollution threshold test of 15 ppm (parts per million) of oil to be discharged. Water is tested and either discharged if clean or recirculated to a holding tank to be separated before being tested again. The tank it is sent back to, the oily water separator, utilizes gravity to separate the fluids due to their viscosity. Ships over 400 gross tons are required to carry the equipment 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 require to log all oil transfer is an oil record book (EPA, 2011).
Cavitation is the process of forming an air bubble in a liquid due to the vaporization of that liquid cause by an area of low pressure. This area of low pressure lowers the boiling point of a liquid allowing it to vaporize into a gas. Cavitation can take place in pumps, which can cause damage to the impeller that moves the fluids through the system. Cavitation is also seen in propulsion. Low pressure pockets form on the surface of the propeller blades as its revolutions per minute increase (IIMS, 2015). Cavitation on the propeller causes a small but violent implosion which could warp the propeller blade. To remedy the issue, more blades allow the same amount of propulsion force but at a lower rate of revolutions. This is crucial for submarines as the propeller needs to keep the vessel relatively quiet to stay hidden. With more propeller blades, the vessel is able to achieve the same amount of propulsion force at lower shaft revolutions.
Marine engineering is predicted to grow approximately 12% from 2016 to 2026. Currently there are about 8,200 naval architects and marine engineers employed, however, this number is expected to increase to 9,200 by 2026 (BLS, 2017). This trend could be attributed to the demand in fossil fuels obtained through offshore drilling and mining. In addition, 90% of the world's trade is done overseas by close to 50,000 ships, all of which require engineers aboard and shoreside (ICS, 2017).
Maritime universities are dedicated to teaching and training students in maritime professions. Marine engineers generally have a bachelor's degree in marine engineering, marine engineering technology, or marine systems engineering. Practical training is valued by employers alongside the bachelor's degree.
- Engine room
- Engineering officer (ship) – Licensed mariner responsible for propulsion plants and support systems
- Marine architecture
- Marine electronics
- Naval architecture – Engineering discipline dealing with the design and construction of marine vessels
- Oceanography – The study of the physical and biological aspects of the ocean
- Kane, J.R. (1971). Marine Engineering. New York: SNAME(page 2-3)
- Bruce A. Wells, (2003) Offshore Petroleum History, American Oil and Gas Historical Society. Retrieved 4/10/14 http://aoghs.org/offshore-exploration/offshore-oil-history/
- Scardino (2009). "Fouling control using air bubble curtains: protection for stationary vessel". Journal of marine engineering and technology.
- "Anti-Fouling Systems". International Maritime Organization. 2018.
- Smith (2018). "Eco Ships:The New Norm for Top Tier Ships". Maritime Reporter and Engineering News.
- "Oily Bilgewater Separators" (PDF). Environmental Protection Agency Office of Wastewater Management United States. 2011.
- "An Introduction to Propeller Cavitation". International Institute of Maritime Surveying. 2015.
- Bureau of Labor Statistics, U.S. Department of Labor. (January 8, 2014) Marine Engineers and Naval Architects, Bureau of Labor Statistics. Retrieved April 2, 2014 http://www.bls.gov/ooh/architecture-and-engineering/marine-engineers-and-naval-architects.htm
- "Occupational Handbook: Marine Engineers and Naval Architects". Bureau of Labor Statistics. October 24, 2017.
- "Shipping and World Trade". International Chamber of Shipping. 2017.
- Society of Naval Architects and Marine Engineers(2013) About SNAME, Society of Naval Architects and Marine Engineers. Retrieved April 2, 2014 http://www.sname.org/Membership1/AboutSNAME