Tanker (ship)
A tanker (or tank ship or tankship) is a
Description
Tankers can range in size of capacity from several hundred tons, which includes vessels for servicing small harbours and coastal settlements, to several hundred thousand tons, for long-range haulage. Besides ocean- or seagoing tankers there are also specialized inland-waterway tankers which operate on rivers and canals with an average cargo capacity up to some thousand tons. A wide range of products are carried by tankers, including:
- Hydrocarbon products such as oil, liquefied petroleum gas (LPG), and liquefied natural gas (LNG)
- Fresh water
- Wine
- Molasses
- Citrus juice
Tankers are a relatively new concept, dating from the later years of the 19th century. Before this, technology had simply not supported the idea of carrying bulk liquids. The market was also not geared towards transporting or selling cargo in bulk, therefore most ships carried a wide range of different products in different holds and traded outside fixed routes. Liquids were usually loaded in casks—hence the term "tonnage", which refers to the volume of the holds in terms of how many tuns or casks of wine could be carried. Even potable water, vital for the survival of the crew, was stowed in casks. Carrying bulk liquids in earlier ships posed several problems:
- The holds: on timber ships the holds were not sufficiently water, oil or air-tight to prevent a liquid cargo from spoiling or leaking. The development of iron and steel hulls solved this problem.
- Loading and discharging: Bulk liquids must be pumped - the development of efficient pumps and piping systems was vital to the development of the tanker. Steam engines were developed as prime-movers for early pumping systems. Dedicated cargo handling facilities were now required ashore too - as was a market for receiving a product in that quantity. Casks could be unloaded using ordinary cranes, and the awkward nature of the casks meant that the volume of liquid was always relatively small - therefore keeping the market more stable.
- Free surface effect: a large body of liquid carried aboard a ship will affect the ship's stability, particularly when the liquid is flowing around the hold or tank in response to the ship's movements. The effect was negligible in casks, but could cause capsizing if the tank extended the width of the ship; a problem solved by extensive subdivision of the tanks.
Tankers were first used by the
Different products require different handling and transport, with specialised variants such as "
Tighter regulation means that tankers now cause fewer environmental disasters resulting from
Design considerations
Many modern tankers are designed for a specific cargo and a specific route.
Tanker capacity
Tankers used for liquid fuels are classified according to their capacity.
In 1954,
- Under 10,000 DWT: Extra small tanker
- 10,000–24,999 DWT: Small tanker
- 25,000–34,999 DWT: Intermediate tanker
- 35,000–44,999 DWT: Medium Range 1 (MR1)
- 45,000–54,999 DWT: Medium Range 2 (MR2)
- 55,000–79,999 DWT: Long Range 1 (LR1)
- 80,000–159,999 DWT: Long Range 2 (LR2)
- 160,000–319,999 DWT: Very Large Crude Carrier (VLCC)
- 320,000–549,999 DWT: Ultra Large Crude Carrier (ULCC)
- 550,000-899,999 DWT: Hyper Large Crude Carrier (HLCC)
- 900,000-1,499,999 DWT: Mega Crude Carrier (MCC)
- Over 1,500,000 DWT: Giga Crude Carrier (GCC)
- Very Large Crude Carrier size range
At nearly 380 vessels in the size range 279,000 t DWT to 320,000 t DWT, these are by far the most popular size range among the larger VLCCs. Only seven vessels are larger than this, and approximately 90 between 220,000 t DWT and 279,000 t DWT.[5]
Fleets of the world
- Flag states
As of 2005, the
- Largest fleets
Greece, Japan, and the United States are the top three owners of tankers (including those owned but registered to other nations), with 733, 394, and 311 vessels respectively. These three nations account for 1,438 vessels or over 36% of the world's fleet.[6]
- Builders
Asian companies dominate the construction of tankers. Of the world's 4,024 tankers, 2,822 (over 70%) were built in South Korea, Japan and China.[6]
Further reading
Petroleum Tables, a book by William Davies, an early tanker captain, was published in 1903, although Davies had printed earlier versions himself.[7] Including his calculations on the expansion and contraction of bulk oil, and other information for tanker officers, it went into multiple editions, and in 1915 The Petroleum World commented that it was "the standard book for computations and conversions."[8]
See also
- History of the oil tanker
- Hydrogen tanker
- List of gas carriers
- List of tankers
- T1 tanker
- T2 tanker
- T3 Tanker
Notes
- ^ Morrell 1931, p. 1.
- ^ "Oil Tanker Spill Statistics 2020" (PDF). www.itopf.org. ITOPF. Retrieved 7 May 2021.
- ^ Morrell 1931, pp. 1, 8.
- ^ Evangelista, Joe, ed. (Winter 2002). "Scaling the Tanker Market" (PDF). Surveyor (4). American Bureau of Shipping: 5–11. Archived from the original (PDF) on 2007-09-30. Retrieved 2008-02-27.
- ^ Auke Visser (22 February 2007). "Tanker list, status 01-01-2007". International Super Tankers. Archived from the original on 2008-09-20. Retrieved 2008-02-27.
- ^ a b c d Office of Data and Economic Analysis (July 2006). "World Merchant Fleet 2001–2005" (PDF). United States Maritime Administration. pp. 3, 5, 6. Archived from the original (.PDF) on 2007-02-21. Retrieved 2008-02-27.
- ^ William Davies, Petroleum Tables; being some useful Tables used for Ascertaining the Weights and Measures of Petroleum Cargoes, and a Table of Distances (London: Goodman, Burnham, and Company, 1903)
- ^ The Petroleum World, Vol. 12 (1915), p. 146
References
- Cambridge Systematics (1998). Multimodal corridor and capacity analysis manual. Transportation Research Board. ISBN 978-0-309-06072-1.
- ISBN 978-1-60239-080-5. Retrieved 2008-02-27.
- Hayler, William B.; Keever, John M. (2003). American Merchant Seaman's Manual. Centerville, MD: Cornell Maritime Press. ISBN 0-87033-549-9.
- Morrell, Robert W. (1931). Oil Tankers (Second ed.). New York: Simmons-Boardman Publishing Company.
- Muller, Gerhardt (1998). "Transportation Modes". In Tompkins, James A.; Smith, Jerry D. (eds.). Warehouse Management Handbook (2nd ed.). Tompkins Press. ISBN 978-0-9658659-1-3.
- Muller, Gerhardt (1995). Intermodal freight transportation (3rd ed.). Intermodal Association of North America.
- Redwood, Boverton (1911). . In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 21 (11th ed.). Cambridge University Press. pp. 316–322.
- Seyoum, Belay (2008). "Trade documents and Transportation". Export–Import Theory, Practices, and Procedures (2nd ed.). Taylor & Francis. ISBN 978-0-7890-3419-9.
- Turpin, Edward A.; McEwen, William A. (1980). Merchant Marine Officers' Handbook (Fourth ed.). Centreville, MD: Cornell Maritime Press. ISBN 0870333798.
- Watts, Philip (1911). . In Chisholm, Hugh (ed.). Encyclopædia Britannica. Vol. 24 (11th ed.). Cambridge University Press. pp. 880–970.
- Wiltshire, Andrew (2008). Looking Back at Classic Tankers. Bristol, England: Bernard McCall. ISBN 9781902953366.
External links
- ship-photos.de: Private homepage of categorized ship photos including tankers of all kinds
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