Water cannon
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A water cannon is a device that shoots a high-pressure stream of water. Typically, water cannons deliver a large volume of water, often over hundreds of feet (tens of metres).
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Fireboats
Water cannons were first devised for use on fireboats. Putting out fires on boats and buildings close to the water was much more difficult and dangerous prior to the invention of fireboats. The first fire boat deployed in Los Angeles was commissioned on August 1, 1919. The first fire boat in New York City was Marine 1, organized February 1, 1891. There may have been other fireboats elsewhere even earlier.
Riot control
On occasion, a stream of water from a fireboat would knock a sailor down, and noting this, someone observed that such a device would be effective at riot control. Truck-based water cannon systems were used widely in the United States during the 1960s for riot control. Despite the fact that they were relatively safe (at least compared to a combination of firearms, tear gas, and batons) their use as a less-lethal riot control mechanism has fallen out of favor in the United States. Pictures of riots being dispersed by water cannons are reminiscent of the civil rights movement when they were used by authorities to disperse crowds of protesting blacks. Perhaps this reminder is one reason that the water cannon has fallen out of favor in the U.S.
Since then alternative, higher-tech non-lethal weapons have been developed for domestic use. Whether these newer weapons are more effective and safe than water cannons remains controversial. Certainly, the competing vendors disagree as to which is more effective and safe.
Water cannons designed for riot control are still manufactured in the United States and the United Kingdom, but most customers are overseas, particularly in Africa and parts of Asia. The most modern versions do not expose the operator to the riot, and are controlled remotely from within the vehicle with a joystick. These high-end vehicles are capable of carrying 2000 gallons (8,000 L) of water with a delivery rate of 250 gallons per minute (15 L/s). The water can be delivered as a continuous stream, or in pulses. There can be no doubt that the water cannon does achieve its goal in taking the wind out of a riot quickly.
Safety of water cannons for riot control
There are several well documented cases where rioters have been killed by other weapons used in conjunction with water cannons. There are also several cases where rioters have killed police while water cannons were being used. There are also no reports of the operator of the water cannon himself being killed.
In a report issued in the United Kingdom, use of plastic bullets over water cannon was justified because, "Water cannon are inflexible and indiscriminate." This despite the fact that several people had been very seriously injured by the plastic bullets. (There was a report that children had been killed by plastic bullets in Ireland, but no specifics were given.)
Anecdotal reports indicate that people can walk away from an encounter with a water cannon while having serious internal injuries such as a ruptured spleen. If true and if such injuries are ignored, death could occur later. Since this type of injury is difficult to self diagnose, you should seek medical attention as soon as possible after an encounter with a water cannon.
The controversy in Israel
An interesting area of controversy with water cannons is in the Israeli-Palestinian conflict. According to the Defence for Children International-Israel Section, some Israelis claim that the Palestinians send their children out during protests to die. The Palestinians of course, flatly deny this. The Israelis claim that the water cannon is ineffective in the Palestinian situation, although it is used routinely against rowdy crowds of Israeli Jews (again according to the DCI).
Effects of the press
The presence of the press at riots has clearly had a significant impact on the use of water cannons. There is a lot of pressure on police departments to avoid bad press. The use of water cannons would undoubtedly play badly in the press, and is likely a key reason that they are not employed more often in countries with a free press.
In 2002 in Salt Lake City, during the Winter Olympics, an unruly crowd was disbursed with just a few pepper ball guns. While covered by the press, it apparently played better on television than the use of water cannons would have. The use of pepper balls has increased significantly with over one million rounds per year being sold now.
In some places, rioters have become semi-professionals, travelling to the sites of likely riots. This is particularly noted in sports-related riots in Europe. For example, France, Poland and England commonly have riots related to soccer matches. Rioters have become quite sophisticated at understanding and withstanding the tactics used by police in such situations. Manuals for successful rioting are available on the Internet. These manuals also encourage rioters to get the press involved, as there is more safety with the cameras rolling. There is also more attention. Citizens with video cameras may also have an effect on both rioters and police.
Dye used in water cannon
In 1997, pink dye was reportedly added to the water used by Indonesian police to disperse a riot. The implication is that they might use this mark to facilitate the arrest of rioters at a later time. The United Kingdom, who sold the water cannons to Indonesia, condemned this practice, but later approved the sale of more water cannons to them.
Soap cannon
Soap cannons have been proposed for crowd control when persons in the crowd may be victims of a suspected bioterror attack. Soap cannons serve the double purpose of crowd control and the cleaning of persons in the crowd. LAX airport has a soap cannon which also features pop-out showers so that crowds can be cleansed after being soaped. Additionally persons who have been soaped up are more likely to remain at the incident site to receive a decontamination treatment (cleansing shower), usually offered after the soaping, so the soap cannon helps to prevent people from fleeing from the scene of a chemical release, i.e. it prevents people from spreading the contamination to others.
Electric water cannons
One manufacturer is experimenting with additives (salt and additives to reduce the breakup of the stream into droplets) that would allow electricity to be conducted through water. They have demonstrated delivery from a distance of up to twenty feet (6 m), but have not yet tested the device on people.
Although referred to as an electrified water cannon, this experiment actually involved a water jet much less powerful than a water cannon.
Opinion of US protesters
Several protest groups in the US have called for the reintroduction of the basic water cannon. It is unclear whether this is to increase safety, or because it furthers their cause through how it might play in the press, or a combination of factors.
Other water delivery devices
Water cannons differ from other similar devices in the volume of water delivered in a given time, the nozzle speed, the pressure at which it is delivered and to a lesser extent the total volume that can be delivered. They are also generally portable. The method of employment is also important in labelling a device a water cannon. Nevertheless, the distinction between a water cannon and other similar devices is fuzzy.
For example, pressure washers generally produce an extremely high pressure stream where the power of the stream drops off significantly over a very short distance. Water pistols and other toys deliver much less water at a much lower pressure with a much lower volume of water. Fire trucks deliver water with much the same force and volume of force as a water cannon, and have even been used in riot control situations, but are rarely referred to as water cannons outside of this context.
Ultra high pressure water jets are used to cut a wide variety of materials including granite, ceramics, fabric and even Kevlar. One such cutter delivers 55,000 lbf/in² (380 MPa) through a nozzle 0.003 inch (8 micrometres) in diameter at 1 kilometre per second. This can cut a person in half at close range. There are reports of accidental deaths involving the industrial use of high-pressure water.de:Wasserwerfer