The adjective submarine means "under the sea" while the noun is a shortened form of submarine boat, a vessel capable of independent operation underwater. While the name usually signifies large, crewed vessels, it can also refer to smaller boats like midget submarines, remotely operated vessels or robots working under the sea. Today's submarines developed from early inventions like the Diving Bell and the Bathysphere.
Early Submarines
With the human race's fascination for exploration, it soon became clear that divers were not able to survive at depths necessary to explore the oceans. The Diving Bell was one of the earliest inventions to facilitate underwater work and exploration. First described by Aristotle in the 4th century BC and used by Alexander the Great to explore the Mediterranean, it was not until 1535 that Guglielmo de Lorena designed and used what is considered the first modern diving bell. Consisting of a rigid chamber used to transport divers to great depths, there were two types, the wet bell and the closed bell. The wet bell was a chamber, open at the bottom, suspended by cables and housing a small number of divers. Water pressure kept the air trapped inside the bell. The divers could not move it, nor could it operate independently because of being tethered. The closed bell had two parts; a sealed unit which was the chamber where the divers lived and a bell which could be locked on and off the chamber and which transported the divers to their destination.
Surprisingly we have to go back to 1620 to find the first moving submersible, although it was not capable of independent movement. Built by Dutchman, Cornelius Drebbel, working for James I of England and designed by mathematician William Bourne, its purpose was underwater exploration and it was propelled by oars. In 2002 a two-person copy of was built for the BBC's "Building the Impossible" and was rowed under water at Dorney Lake at Eton.
It was not long before the military potential of submarines was recognised and in 1648 Bishop John Wilkins of Chester mentioned the submarine's strategic advantages in his "Mathematicall Magick". These included:-
- Ability to travel invisibly to any coast without discovery.
- Safety from tides, tempests, ice, pirates and robbers.
- A useful tool against naval enemies.
- A means of conveying supplies secretly to anywhere accessible by water.
- A vehicle for conducting underwater experiments.
The Bathysphere was a much later invention, designed in 1928 by the American Otis Barton for studying underwater wildlife. Setting several world records for the deepest dive by a human, it consisted of a hollow sphere with windows made of fused quartz and an entrance hatch which was bolted down before submersion. Oxygen was supplied from high pressure cylinders inside the vessel while CO2 and moisture were absorbed by pans of calcium chloride and soda lime inside the walls. Cables lowered and raised it and provided telephone communication between divers and surface.
By the end of the 19th century subs had been adopted by several navies. They were widely used in World War I for attacking enemy surface vessels or other submarines, blockade running and reconnaissance. Civilian uses included marine science, salvage, exploration and inspection and maintenance. They also had specialised functions like search-and-rescue, undersea cable repair and archaeology.
Submarine Design
Traditionally submarines were cylindrical in shape, with conical or hemispherical ends. Their "working" section was a vertical structure, usually in the middle of the vessel, which housed the communications and sensing devices and the periscopes. Americans call this the "sail" while in Europe it is known as the "fin". In early vessels there was a separate pressure hull above the main body, called the "conning tower", from which short periscopes could be used. The first simple fixed periscope using mirrors was built in 1854 but was superseded by a prismatic version in 1861, after which they were regularly used in submarines. The propeller was located at the rear, along with hydrodynamic control fins and ballast tanks. Some of the specialised smaller submarines varied significantly from this design.
The wide variety of submarine types ranges from one or two-person vessels that can stay under water for a few hours, to larger versions capable of submersion for as long as six months at a time.
Some Notable Submarines
- The Turtle
This was the first military submarine and the earliest one capable of independent underwater operation. Built in America in 1775, it held one person and used screws for propulsion. It was designed for use against the British Royal Navy as a means of attaching explosive charges to ships in harbour.
- The Alligator
This was the first U.S. Navy submarine, launched in 1862 and was the first submarine to use compressed air and an air filtration system. Although initially propelled by hand powered paddles, it was soon converted to a screw propeller powered by a hand crank. It was the largest American Civil War submarine, measuring 14 metres by 1 metre.
- The Plongeur
This was the first submarine not relying on human propulsion. It was launched by the French in 1863 and used a compressed-air engine. Air was stored in 23 tanks taking up a huge amount of space and resulting in the vessel measuring a massive 43 metres in length. It was armed with a torpedo and a ram to break holes in enemy ships.
- Ictineo II
Designed in 1864 in Spain, it was the first submarine powered by an air independent engine, measured 14 metres, held a crew of two and could remain submerged for two hours. The double-hulled vessel solved many of the pressure and buoyancy control problems which had bothered earlier subs.
- Nautilus
In 1870 the fictitious Nautilus, which figured in Jules Verne's 20,000 Leagues under the Sea, was more advanced than any real submarine and inspired inventors world wide to improve on the current designs.
- Fenian Ram and Holland VI
Launched in 1881, Fenian Ram was the first submarine designed by the Irish inventor John Philip Holland, using internal combustion engines on the surface and electric battery power when submerged. Its successor Holland VI was launched in 1897 and purchased by the United States Navy; their first commissioned submarine. Holland submarines were the first mechanically powered subs to be put into service by the navies of Great Britain, Japan Russia and the U.S.
- U-boats
World War I saw submarines making a significant impact. German U-boats were responsible for sinking Britain's Lusitania, which was one of the reasons for the U.S. entering into the war. Their tactics were to operate primarily on the surface using their regular engines, then submerging to attack using battery power. In cross-section they were triangular with a keel to minimise rolling when on the surface. During the war U-boats were responsible for sinking more than 5,000 Allied ships.
- Submarine Aircraft Carriers
These were developed between the two world wars and equipped with waterproof hangar and steam catapult to launch and recover small seaplanes. They acted as a reconnaissance unit ahead of the fleet in the days before radar. By World War II Germany had the largest submarine fleet and used it with devastating effect, but with technical advances like radar and sonar the Allies were able to detect their positions, attack them and route their convoys around them.
- The Russian Typhoon Class
Named "Akula" meaning "Shark" by the Russians and "Typhoon" by NATO, these were the biggest ever built measuring 175 metres in length and 23 metres in width. They were nuclear-powered ballistic missile submarines used by the Soviet Navy in the 1980s and were quieter and more manoeuvrable than their forerunners. They had six torpedo tubes for launching a variety of torpedoes, missiles and mines. They could stay submerged for at least 120 days and incorporated civilised living conditions for their crews. They featured multiple pressure hulls which made them much wider than traditional subs. Two pressure hulls were positioned parallel with each other with a third above them and two more for the torpedoes and steering gear. This made them much safer than the older types of vessel, as even if one of the hulls was breached, the crew could remain safe and there was far less risk of flooding. They patrolled under the Arctic ice cap from where they could surface to launch their missiles, safe from enemy subs and anti-submarine forces. They reached the end of their service in 2012 when the Russians decided that modernising them would be too expensive.
- The Borei Class
These 4th generation nuclear-powered missile submarines were introduced to replace the Typhoon. They have a more compact and hydrodynamically efficient hull and use pump-jet propulsion for the first time. They are smaller than the Typhoon at 170 metres long and 13 metres wide, with a submerged speed of about 46 kilometres per hour and can carry 16 missiles.
Author – Dee White