Wednesday, September 26, 2007

SUBMARINE

Submarines

From Mary Bellis </mbiopage.htm>,
History and Design of Submarines

Designs for underwater boats or submarines date back to the 1500s and ideas for underwater travel date back even further. However it was not until the 19th century that the first useful submarines began to appear. During the Civil War, the Confederates built the H.L. Hunley,the submarine that sank a Union ship. The U.S.S. Housatonic was built in 1864. But it wasn't until after World War I began that the first truly practical and modern submarines were invented.

Early History of the Submarine

The submariner's problem has always been how to improve his underwater endurance and performance, and both capabilities are defined by the ship. Early in submarine history the submariner's problem often was how to make his ship work at all.

Hollow Papyrus Reeds

Historical accounts point out that man has always sought to explore the ocean depths. An early record from the Nile Valley in Egypt gives us the first illustration. It is a wall painting that shows duck hunters, bird spears in hand, creeping up to their prey beneath the surface as they breathe through hollow papyrus reeds. The Athenians are said to have used divers to clear the harbor entrance during the siege of Syracuse.

And Alexander the Great, in his operations against Tyre, ordered divers to destroy any submersible vehicle (submarine) defenses the city might undertake to build.

While in none of these records does it actually say that Alexander had any kind of submersible vehicle, legend has it that he descended in a device that kept its occupants dry and admitted light.

William Bourne - 1578

Not until 1578 did any record appear of a craft designed for underwater navigation. William Bourne, a former Royal Navy gunner, designed a completely enclosed boat that could be submerged and rowed beneath the surface. His creation was a wooden framework bound in waterproofed leather. It was to be submerged by using hand vises to contract the sides and decrease the volume.

Although Bourne's idea never got beyond the drawing board, a similar apparatus was launched in 1605. But it didn't get much farther, because the designers had neglected to consider the tenacity of underwater mud. The craft became stuck in the river bottom during its first underwater trial.

Cornelius Van Drebbel - 1620

What might be called the first "practical" submarine was a rowboat covered with greased leather. It was the idea of Cornelius Van Drebbel </library/inventors/bldrebbel.htm>, a Dutch doctor living in England, in 1620. Van Drebbel's submarine was powered by rowers pulling on oars that protruded through flexible leather seals in the hull. Snorkel air tubes were held above the surface by floats, thus permitting a submergence time of several hours. Van Drebbel's submarine successfully maneuvered at depths of 12 to 15 feet below the surface of the Thames River.

Van Drebbel followed his first boat with two others. The later models were larger but they relied upon the same principles. Legend has it that after repeated tests, King James I of England rode in one of his later models to demonstrate its safety. Despite its successful demonstrations, Van Drebbel's invention failed to arouse the interest of the British Navy. It was an age when the possibility of submarine warfare was still far in the future.

Giovanni Borelli - 1680

In 1749 the British periodical "Gentlemen's Magazine" printed a short article describing a most unusual device for submerging and surfacing. Reproducing an Italian scheme developed by Giovanni Borelli in 1680, the article depicted a craft with a number of goatskins built into the hull. Each goatskin was to be connected to an aperture at the bottom. Borelli planned to submerge this vessel by filling the skins with water, and to surface it by forcing the water out with a twisting rod. Even though Borelli's submarine was never built it provided what was probably the first approach to the modern ballast tank.

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