An icebreaker is a special purpose ship or boat designed to move and navigate through ice-covered waters. Although this article mainly discusses icebreaking ships, the term can refer to smaller vessels (e.g., icebreaking boats that were used on the Canals of Great Britain in the days of commercial carrying).
For a ship to be considered an icebreaker it requires three components: a strengthened hull, an ice-clearing shape, and the power to push through, none of which are possessed by most normal ships.
To pass through ice-covered water, an icebreaker uses its great momentum and power to drive its bow up onto the ice, breaking the ice under the immense weight of the ship. Because a buildup of broken ice in front of a ship can slow it down much more than the breaking of the ice itself, the speed of the ship is increased by having a specially designed hull to direct the broken ice around or under the vessel . The external components of the ship's propulsion system (propellers, propeller shafts, etc.) are at even greater risk of damage than the vessel's hull, so the ability for an icebreaker to propel itself onto the ice, break it, and successfully clear the debris from its path is essential for its safety.
Historypolar exploration, ice-strengthened ships were used. These were originally wooden and based on existing designs, but reinforced, particularly around the waterline with double planking to the hull and strengthening cross members inside the ship. Bands of iron were wrapped around the outside. Sometimes metal sheeting was placed at the bows, stern and along the keel. Such strengthening was designed to help the ship push through ice and also to protect the ship in case it was "nipped" by the ice. Nipping occurs when ice floes around a ship are pushed against the ship trapping it as if in a vice and causing damage. This vice-like action is caused by the force of winds and tides on ice formations. Although such wind and tidal forces may be exerted many miles away, the ice transmits the pressure.
It is supposed that the first steam-powered icebreaker had been built in Kronstadt, Russia in 1864. The icebreaker was known as Pilot.
At the beginning of the 20th Century several countries began to operate purpose-built icebreakers. Most were coastal icebreakers, but Russia and later the Soviet Union also built several oceangoing icebreakers of around 10,000 tonnes displacement. Several technological advances were introduced over the years, but it was not until the introduction of nuclear power in the Soviet icebreaker Lenin in 1959 that icebreakers developed their full potential.
Function of icebreakersIcebreakers are needed to keep trade routes open where there are either seasonal or permanent ice conditions. Icebreakers are expensive to build and very expensive to run, whether the icebreaker is powered by gas turbines, diesel-electric powerplant or nuclear energy. They are uncomfortable to travel in on the open sea: almost all of them have thick, rounded keels, and with no protuberances for stability, they can roll even in light seas. They are also uncomfortable to travel in when breaking through continuous thick ice due to constant motion, noise, and vibration.
A modern icebreaker typically has shielded propellers both at the bow and at the stern, as well as side thrusters; pumps to move water ballast from side-to-side; and holes on the hull below the waterline to eject air bubbles, all designed to allow an icebreaker stuck amidst thick ice to break free. Many icebreakers also carry aircraft (formerly seaplanes and now helicopters) to assist in reconnaissance and liaison.
The shape optimal for moving through ice makes icebreakers uncomfortable in open water and gives them poor fuel efficiency.
Icebreakers tend to roll side to side to the discomfort of the crew. Some new icebreakers such as the USCGC Healy make use of anti-roll tanks. Anti-roll tanks use computer controlled pumps to rapidly shift ballast water side-to-side to keep the vessel upright.
A greater concern is how well a ship cuts through waves. The ability of a ship to cut through waves can greatly affect its fuel efficiency and even its safety in a storm. Most ships use a sharp or bulbous bow to cut through waves and help prevent waves from slamming the bow of the ship. However, icebreakers have a round sled-like bow. They tend to slam into waves, which can be a risk in high seas.
Recent advances in ship propulsion have produced new experimental icebreakers. Electrically driven propellers are mounted to steerable pods under the ship. These Azimuthing Podded Propulsors, or Azi-pods, improve fuel efficiency, ship steering, ship docking, and remove the need for rudders. Azipods also allow a ship to travel backwards as easily as it travels forwards. The double acting icebreaker is unique because its stern is shaped like an icebreaker's bow. Normally travelling forward, a double acting icebreaker uses a conventional ship bow for a more comfortable ride. When ice is encountered, the ship turns around and travels backwards through the ice. The MT Mastera and MT Tempera are two vessels using this new technology.
In the 1980s hovercraft were shown to be effective as icebreakers on rivers. Instead of displacing or crushing the ice from above, they work by injecting a bubble of air under the ice sheet, causing it to break off and be swept downstream by the current. The purpose is usually not to provide navigation channels, rather, to prevent ice dams from forming on bridge structures, thus damaging them and causing local flooding.
Notable icebreakersArgentine Navy
- CCGS Louis S. St-Laurent
- CCGS Terry Fox
- CCGS John A. MacDonald (Decommissioned 1991 and scrapped 1994)
- CCGS D'Iberville (Decommissioned and scrapped)
- CCGS N.B. McLean (Decommissioned and scrapped)
- CCGS Alexander Henry (decommissioned)
- CCGS Amundsen (ex. CCGS Sir John Franklin)
- CCGS Des Groseilleirs
- CCGS Henry Larsen
- CCGS Labrador (decommissioned)
- CCGS Pierre Radisson
- CCGS Sir John Franklin (now CCGS Amundsen)
- CCGS Ernest Lapointe (Decommissioned, now museum ship)
- CGS Mikula (Long ago decommissioned)
- CGS Northern Light (Decommissioned and sold, long ago)
- CCGS Samuel Risley
- CCGS Ann Harvey (St. John's, NL)
- CCGS Edward Cornwallis (Dartmouth, NS)
- CCGS George R. Pearkes
- CCGS Griffon
- CCGS J.E. Bernier (Decommissioned)
- CCGS Martha L. Black (St. John's, NL)
- CCGS Sir Wilfred Laurier
- CCGS Sir William Alexander (Dartmouth)
- CCGS Earl Grey (Charlottetown, PEI)
- CCGS Bartlett (Decommissioned)
- CCGS Provo Wallis
- CCGS Simcoe (Built 1962)
- CCGS Tracy
- CCGS Cygnus
- CCGS Leonard J. Cowley
- CCGS Sir Wilfred Grenfell
- Arctic Kalvik
- MV Polar Star
- MV Xue Long
- Icebraker A551 Danbjørn
- Icebraker A552 Isbjørn
- Icebraker A553 Thorbjørn
Finnish Maritime Administration
Maritime Museum of Finland
- MS Tarmo in Kotka
- KV Svalbard icebreaker and coast guard vessel
- Kapitan Dranitsyn
- Vladimir Ignatyuk
- Kapitan Khlebnikov
- Saint Alexander Nevsky
- Atle I (formerly known as Statsisbrytaren)
- Ymer I
- Oden I
- Atle II
- Ymer II
- Oden II
- Tor Viking
- Vidar Viking
- Balder Viking
- HMS Endurance
- RRS James Clark Ross
- Laurence M. Gould
- Nathaniel B. Palmer
- USCGC Mackinaw (WAGB-83)
- USCGC Staten Island (WAGB-278)
- USCGC Eastwind (WAGB-279)
- USCGC Southwind (WAGB-280)
- USCGC Westwind (WAGB-281)
- USCGC Northwind (WAGB-282)
- USCGC Burton Island (WAGB-283)
- USCGC Edisto (WAGB-284)
References1. ^ R/V Laurence M. Gould. National Science Foundation. Retrieved on 2007-08-16.
2. ^ R/V Nathaniel B. Palmer. National Science Foundation. Retrieved on 2007-08-16.
ship is a large watercraft capable of offshore navigation. Ships may be operated by:
- "Ice heroes": Read a Q&A with Canadian Coast Guard acting commanding officer
- Canadian Geographic: View a Canadian Coast Guard slideshow
- Pushing the Limits Short history of Russian icebreakers by Roderick Eime
- Governments (military, rescue, research, transportation)
- Private companies and institutions (transportation, offshore resources, research)
- Individuals (large yachts, research).
..... Click the link for more information.A boat is a watercraft designed to float or plane on, and provide transport over, water. Usually this water will be inland (lakes) or in protected coastal areas. However, boats such as the whaleboat were historically designed to be operated from a ship in an offshore environment.
..... Click the link for more information.ICE may refer to:
- Internal combustion engine, a fuel engine
- In case of emergency, the emergency contact program created after the 7 July 2005 London Bombings
- International Cometary Explorer, a former spacecraft
- Integrated Collaboration Environment
..... Click the link for more information.Ships is a Japanese clothing brand, founded in 1975. The president of the company is Yoshinori Miura.
- SHIPS official homepage
..... Click the link for more information.goods was dying out, there was a rise in interest in their history and potential use for leisure. A large amount of credit for this is usually given to L. T. C. Rolt, whose book "Narrowboat" about a journey made in nb Cressy was published in 1944.
..... Click the link for more information.A hull is the body of a ship or boat. It is a central concept in floating vessels as it provides the buoyancy that keeps the vessel from sinking.
General featuresNearly all watercraft, from small boats to the largest ships, adhere to a general form that serve the needs of
..... Click the link for more information.bow (pronounced to rhyme with how) is a nautical term that refers to the forward part of the hull of a ship or boat, the point that is most forward when the vessel is underway. Both of the adjectives fore and forward mean towards the bow.
..... Click the link for more information.propeller is essentially a type of fan which transmits power by converting rotational motion into thrust for propulsion of a vehicle such as an aircraft, ship, or submarine through a fluid such as water or air, by rotating two or more twisted blades about a central shaft, in a
..... Click the link for more information.Polar exploration is the physical exploration of the Arctic and Antarctic regions of the Earth. It is also denotes the historical period during which mankind most intensely explored the regions north of the Arctic Circle and south of the Antarctic Circle.
..... Click the link for more information.Waterline refers to an imaginary line marking the level at which ship or boat floats in the water. To an observer on the ship the water appears to rise or fall against the hull .
..... Click the link for more information.Kronstadt (Russian: Кроншта́дт), also spelled Kronshtadt, Cronstadt (German: Krone for Crown and Stadt
..... Click the link for more information.Anthem
Hymn of the Russian Federation
(and largest city) Moscow
..... Click the link for more information.Pilot (Russian: Пайлот) was a Russian icebreaker, often referred to as the world's first steam-powered icebreaker.
Pilot had been built as steam-powered propeller thug.
..... Click the link for more information.twentieth century of the Common Era began on January 1, 1901 and ended on December 31, 2000, according to the Gregorian calendar. Some historians consider the era from about 1914 to 1991 to be the Short Twentieth Century.
..... Click the link for more information.Anthem
Hymn of the Russian Federation
(and largest city) Moscow
..... Click the link for more information.Union of Soviet Socialist Republics (abbreviated USSR, Russian:; tr.
..... Click the link for more information.Nuclear power is a type of nuclear technology involving the controlled use of nuclear fission to release energy for work including propulsion, heat, and the generation of electricity.
..... Click the link for more information.NS Lenin is an icebreaker launched in 1957, and is both the world's first nuclear powered surface ship and the first nuclear powered civilian vessel. Lenin was put into operation in 1959 and officially decommissioned in 1989.
..... Click the link for more information.gas turbine extracts energy from a flow of hot gas produced by combustion of gas or fuel oil in a stream of compressed air. It has an upstream air compressor (radial or axial flow) mechanically coupled to a downstream turbine and a combustion chamber in between.
..... Click the link for more information.A number of vehicles use a diesel-electric powertrain for providing locomotion. A diesel-electric powerplant includes a diesel engine connected to an electrical generator, creating electricity that powers electric traction motors.
..... Click the link for more information.nuclear powered icebreaker is a purpose-built ship for use in waters continuously covered with ice. Icebreakers are ships capable of cruising on ice-covered water by breaking through the ice with their strong, heavy, steel bows.
..... Click the link for more information.Stability can refer to:
- Aircraft flight Stability (aircraft)
- Atmospheric stability, a measure of the turbulence in the ambient atmosphere
- BIBO stability (Bounded Input, Bounded Output stability), in signal processing and control theory, part of electrical
..... Click the link for more information.seaplane is a fixed-wing aircraft designed to take off and land (or "alight") upon water. Seaplanes can be divided into separate categories such as float planes, flying boats, and amphibious aircraft ("amphibians").
..... Click the link for more information.helicopter is an aircraft which is lifted and propelled by one or more horizontal rotors, each rotor consisting of two or more rotor blades. Helicopters are classified as rotorcraft or rotary-wing aircraft to distinguish them from fixed-wing aircraft because the helicopter derives
..... Click the link for more information.USCGC Healy is a research icebreaker put into commission in 1999 by the United States Coast Guard. She was constructed by Avondale Industries in New Orleans, Louisiana and named in honor of Captain "Hell Roaring" Michael A. Healy U.S.R.C.S.
..... Click the link for more information.bulbous bow, a feature of many modern ship hulls, is a protruding bulb at the bow (or front) below the waterline. Usually visible only when a ship is in drydock, the bulb modifies how water flows around the hull, reducing drag and increasing in speed, range, and fuel efficiency.
..... Click the link for more information.Azimuth thruster is a configuration of ship propellers placed in pods that can be rotated in any horizontal direction. A conventional rudder is not needed. These give ships better maneuverability than a fixed propeller and rudder system.
..... Click the link for more information.The MT Mastera and its sister ship the MT Tempera are icebreakers known as double acting tankers. They use Azipod azimuth thruster technology. The MT Mastera was finished in 2002.
..... Click the link for more information.The MT Tempera is an ocean-going icebreaking tanker that was finished in 2002.
Using Azipod technology, the MT Tempera and its sister ship the MT Mastera are known as double acting tankers.
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- Nathaniel B. Palmer
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