Submarines




I was always fasinated with under water vehicles, like the car in the 007 James Bond film "The Spy Who Loved Me" or the fantasy film called "20,000 Leagues Under The Sea". Although experimental submarines had been built before, submarine design took off during the 19th century. Submarines were first widely used in World War I, and feature in many large navies. Military usage ranges from attacking enemy ships or submarines, aircraft carrier protection. Civilian uses for submarines include marine science, salvage, exploration and facility inspection/maintenance. Submarines can also be specialised to a function such as search and rescue, or undersea cable repair. Submarines are also used in tourism and for academic research. Originally, submarines were once human propelled. The first mechanically driven submarine was the 1863 French Plongeur, which used compressed air for propulsion. Anaerobic propulsion was first employed by the Spanish Ictineo II in 1864. Ictineo's engine used a peroxide compound to generate heat for steam propulsion, while also providing oxygen for the crew. Until the advent of nuclear marine propulsion, most 20th century submarines used batteries for running underwater and gasoline (petrol) or diesel engines on the surface, and for battery recharging. Early submarines used gasoline, but this quickly gave way to kerosene (paraffin), then diesel, because of reduced flammability. Diesel-electric became the standard means of propulsion. A submarine will have a variety of sensors determined by its missions. Modern military submarines rely almost entirely on a suite of passive and active sonars to find their prey.

Modern military submarines use an inertial guidance system for navigation while submerged, but drift error unavoidably builds up over time. All submarines need facilities to control their motion. Military submarines also need facilities to operate their sensors and weapons. As for the crew a typical nuclear submarine has a crew of over 80. Non-nuclear boats typically have fewer than half as many. The conditions on a submarine can be difficult because crewmembers must work in isolation for long periods of time, without family contact. Submarines normally maintain radio silence to avoid detection. Operating a submarine is dangerous, even in peacetime, and submarines have been lost in accidents.

With nuclear power, submarines can remain submerged for months at a time. While the greater endurance and performance from nuclear reactors makes nuclear submarines better for long-distance missions or the protection of a carrier battle-force they have the technical limitation in stealthiness as the reactor always have to be chilled with the inherent noise it brings from pumps. As early as 1666, English writer Margaret Cavendish wrote Blazing World - one of the earliest science fiction books - which included the depiction of a naval war fought by submarines, towed by "fish-men".