Ship canals can be distinguished from barge canals, which are intended to carry barges and other vessels specifically designed for river and/or canal navigation. Ships capable of navigating large bodies of open water typically have more draft, and are higher above the water than vessels for inland navigation. A ship canal therefore typically offers deeper water and higher bridge clearances than a barge canal suitable for vessels of similar length and width constraints.
Ship canals may be specially constructed from the start to accommodate ships, or less frequently they may be enlarged barge canals or canalized or channelized rivers. There are no specific minimum dimensions for ship canals, with the size being largely dictated by the size of ships in use nearby at the time of construction or enlargement.
Ship canals may be constructed for a number of reasons, including:
- To create a shortcut and avoid lengthy detours.
- To create a navigable shipping link between two land-locked seas or lakes.
- To provide inland cities with a direct shipping link to the sea.
- To provide an economical alternative to other options.
Early canals were connected with natural rivers, either as short extensions or improvements to them.
One of the first canals built was the Grand Canal of China, which was developed over a long period starting in the 5th century BCE. In the modern era, canals in the United Kingdom are typically associated with the Duke of Bridgewater, who hired the engineer James Brindley and had the first canal (the Bridgewater Canal) built that ran over a flowing river.
In the United States, the canal that brought about an age of canal building was the Erie Canal. It was a long-sought-after canal and connected the Great Lakes to the Hudson River. This canal initiated a half-century-long boom of canal building and brought about many new features that allowed canals to be used in different areas previously inaccessible to canals. These features include locks, which allow a ship to move between different altitudes, and puddling, which waterproofed the canal.
Notable ship canals
|Length||Maximum boat length
x beam x draft (m)
|Start point||End point|
|White Sea–Baltic Canal||1933||227 km (141 mi)||135 x 14.3 x 4||Russia: Lake Onega||Baltic Sea in Saint Petersburg|
|Rhine–Main–Danube Canal||1992||171 km (106 mi)||190 x 11 x 4||Germany: Main at Bamberg||Danube at Kelheim|
|Suez Canal||1869||193.3 km (120.1 mi)||Unlimited x 78 x 20||Egypt: Port Said||Port Tewfik|
|Volga–Don Canal||1952||101 km (63 mi)||141 x 17 x 4||Russia: Volgograd||Tsimlyansk Reservoir|
|Kiel Canal||1895||98 km (61 mi)||310 x 42 x 14||Germany: Brunsbüttel||Kiel|
|Houston Ship Channel||1914||80 km (50 mi)||305 x 161 x 14||United States: Houston||Gulf of Mexico|
|Panama Canal||1914||77 km (48 mi)||366 x 49 x 15||Panama: Caribbean||Pacific Ocean|
|Danube–Black Sea Canal||1984||64.4 km (40.0 mi)||138 x 17 x 6||Romania: Danube at Cernavodă||Black Sea at Agigea|
|Manchester Ship Canal||1894||58 km (36 mi)||183 x 20 x 9||United Kingdom: Eastham Locks||Salford Quays|
|Welland Canal||1932||43.4 km (27.0 mi)||226 x 24 x 8||Canada: Lake Ontario at Port Weller||Lake Erie at Port Colborne|
|Saint Lawrence Seaway||1959||600 km (370 mi)||226 x 24 x 8||Canada: Port Colborne||Canada: Montreal|
The standard used in the European Union for classifying the navigability of inland waterways is the European Agreement on Main Inland Waterways of International Importance (AGN) of 1996, adopted by The Inland Transport Committee of the United Nations Economic Commission for Europe (ECE), which defines the following classes:
|Class||Tonnage (t)||Draught (m)||Length (m)||Width (m)||Air draught (m)||Description|
|Class IV||1,000–1,500||2.5||80–85||9.5||5.2–7.0||Johann Welker|
|Class Va||1,500–3,000||2.5–2.8||95–110||11.4||5.2–7.0–9.1||Large Rhine|
- Frederick Augustus Porter; Barnard, Arnold Guyot (1883). Johnson's New Universal Cyclopædia. A. J. Johnson & Company. p. 1160. Retrieved 15 June 2020.
- Finch, Roy (1925). The Story of the New York State Canals (PDF) (booklet). p. 11. Retrieved 15 June 2020.
- Engineering News and American Railway Journal. Engineering News Publishing Company. 1897. p. 317,320. hdl:2027/uc1.e0000401679. Retrieved 15 June 2020.
- Harrington, L. (1974). The Grand Canal of China. Bailey and Swinfen. p. 11. ISBN 9780561002163. Retrieved 4 July 2020.
- Johnson's 1883, p. 1660.
- Finch 1925, p. 11.
- Engineering News 1897, p. 317,320.
- "History of canals in Great Britain". www.canalmuseum.org.uk. Archived from the original on 8 October 2019. Retrieved 30 October 2018.
- Harrington 1974, p. 11.
- "Canals 1750 to 1900 – History Learning Site". History Learning Site. Archived from the original on 30 October 2018. Retrieved 30 October 2018.
- "The Canal Era". www.ushistory.org. Archived from the original on 7 March 2016. Retrieved 30 October 2018.
- "European Agreement on the main Inland Waterways of international importance (AGN)" (PDF). United Nations. p. 343. Retrieved 30 November 2008.[dead link]
- "UNECE Homepage". www.unece.org. Archived from the original on 15 May 2020. Retrieved 15 June 2020.
- Media related to Canals at Wikimedia Commons