Of all the machines created by man, submarines are without doubt the most secret and mysterious. They hide in invisible caves carved into the rock and move silently in the sea scaring even sharks.
But the path traveled by man to reach these modern atomic-powered giants (created primarily for diving, as opposed to submersibles, which frequently have to return to the surface to navigate underwater) has been very long and eventful.
One of the first submersible projects is due to Leonardo da Vinci . This brilliant artist and scientist, however, was struck by a question: would men take advantage of his invention to sink ships? Leonardo did not reveal the secrets of his machine to avoid this risk.
The first working submersible was built in 1624 by the Dutchman Cornelius van Drebbel. It was a kind of wooden boat whose upper part was covered with leather and metallic ballast; it moved by means of six fins that protruded laterally from the hull.
Van Drebbel inaugurated his apparatus on the Thames in the presence of King James I and a crowd of Londoners. It seems that the strange ship managed to navigate for a few kilometers while staying a few meters deep.
Leonardo’s fears about man’s misuse of the submersible were soon shown to be well founded. Indeed, in 1776 the American David Bushnell built the first military submersible : the “Tortuga”. as he called his machine, it was like a large six-foot-tall egg made of iron sheets and boards.
It had a rudder, two crank propellers, two ballast tanks, and an observation tower. The armament consisted of a gunpowder barrel that had to be hooked, by means of a large screw, to the hull of the enemy ship. The explosion was later caused by a clockwork mechanism. The crew consisted of only one man.
The immersion and emersion system of the “Tortuga” worked like this: the submersible, under normal conditions, floated; to cause it to sink a hatch was opened and water was allowed to enter the ballast tanks.
The submersible was gaining weight and gradually went to the bottom. To rise to the surface, the pilot had to extract the water by means of a pump, and the apparatus slowly floated up again. The first mission of the «Tortuga» failed, since the hull of the enemy ship had a copper cover and the pilot did not manage to screw the bomb.
In the 19th century there were numerous and increasingly improved models of submersibles: the French ” Gymote “, which had electric motors and could navigate 200 kilometers under water at five kilometers per hour.
The American ‘Pluger II’ ‘, in 1895, with a steam engine and torpedo tubes, and many more. Two Spaniards deserve special mention here: first, the Catalan Narciso Monturiol (1819-1885), born in Figueras (Gerona), who is often considered the inventor of the submarine , which he called “ Ictíneo ” and was successfully experimented on in 1859; secondly, Isaac Peral (1851-1895), born in Cartagena, whose projects failed due to lack of official help, after a series of quite satisfactory trials.
The First World War meant the consolidation of the submersible, already improved in all its details: the German U-Boats confirmed once again Leonardo’s forecasts.
The submersibles of World War II did not undergo noticeable improvements; in the postwar period, modified the traditional motors, higher speeds were reached. Finally, in 1954, the United States Navy launched the “Nautilus”, the first atomic submarine .
In 1958, for the first time, the “Nautilus” sailed under the ice of the North Pole, traveling the polar route from Alaska to England. Atomic submarines are plentiful today: they are capable of diving at more than 60 kilometers per hour and remain underwater for a year at a time, and they carry a crew of more than 100 men.
The experiences acquired in the construction of war submarines, and thanks to the new instruments that make diving safer today, are expected to be applied to passenger and freight ships in the future.
They will be colossal submarines that will navigate under the surface of the oceans, in the calm deep waters, safe from storms, thus giving this advance a peaceful use.