The nuclear submarine
The modern conventional submarine
Inside German WW2 submarines
The Type VIIC submarine
Less than two centuries mediate between the humble Turtle, sort of wooden barrel propelled by cranks,
and the Thomas Jefferson, first nuclear ballistic submarine and exponent of the most destructive type of weapon ever deployed.
During the 19th century a good number of inventors from several countries tried to take advantage of all the technical progress
achieved during the industrial revolution. What during former centuries seemed an impossible quest was becoming more and more
feasible for the new generations of engineers, and at the end of the century several models existed which were able to transport
their own engine and armament.
Not much later, during the First World War, it was finally seen the effectiveness of the submarine weapon and the dramatic
consequences that it brought, represented by several millions of tonnes of merchant ships sunk during the two world wars.
The promising qualities of the submarine weapon suffered a momentaneous drawback during the second half of the Second World War,
but the technical advances applied during the immediate postwar years returned the submarine weapon to its former status quo.
The dramatic characteristics that have been inherent of the submarine weapon already from its inception (stealth attack, devastating
underwater shockwave and a prominent danger for the own crews) were greatly emphasized by the apparition of submarines capable of
remaining submerged during months and launching an array of intercontinental ballistic missiles from beneath the waters. To
achieve this, also the size of the submarines had to grow dramatically.
The Turtle: first submersible vessel
The first military operation performed by means of a submersible vessel has been credited to the contraption created by David
Bushnell in 1775, called "Turtle", and happened in the context of the American War of Independence. In the night of the
6th September 1776, Sergeant Ezra Lee of the United States departed onboard the Turtle to approach the HMS Eagle, a third-rate
ship of the line of the Royal Navy anchored in the port of New York, with the purpose of sinking it. Due to the obvious limitations
of Bushnell's submersible vessel this had to be a difficult mission; and indeed, difficulties soon arose.
Once the tugboats released the Turtle, the strong water flow pushed the tiny vessel far from the HMS Eagle, and as a result Lee
had to turn the cranks during two hours until reaching the enemy flagship. The planned procedure was to place the Turtle just
beneath the hull of the HMS Eagle, to drill a hole on it to attach the clockwork bomb that the Turtle carried in a box attached
to her wooden body. Like many other warships of those years the HMS Eagle had her underwater body lined with copper sheets
to prevent Teredo worms from making holes on it. Because of this, or more probably because of the very poor stability of the
Turtle, another difficulty arose.
Regardless of his efforts, Lee could not pierce the hull, so he had to abort the mission and escape. But troubles would not end
there, for the Turtle was detected and thereafter chased by rowing boats, which would have no difficulty in catching a barrel-like
vessel propelled by rudimentary screws attached to manually operated cranks. Lee had to play the only card available to him in
that troubled moment, so he released the bomb hoping that an explosion in the water would neutralize or disband his persecutors;
these, who were not fools, intuited the trick and gave up on the chase.
From the "Turtle" to the "Fish-like"
Influenced by the design of the Turtle, several submersible models were developed during the first half of the 19th century. But
as their predecessor, these were largely rudimentary contraptions that achieved little success. The hulls of the new models had
an elongated shape to increase the hydrodynamical efficiency and, when the budget allowed it, they were built of metal instead of
wood. Propulsion was achieved through manually-operated cranks, sometimes associated to gear sets, and the model built by Robert
Fulton in 1800, in the late stages of the Age of Sail, had a removable rigging as well. Fulton built a copper hull which had a
ballast tank in its lower part to enable it to submerge into and emerge from the sea. He tested his vessel in the Seine river in
an attempt to elicit the interest of Napoleon, but the Emperor showed no enthusiasm for the idea.
German inventor Wilhelm Bauer built in Kiel, in 1850, a strange 8-meter long vessel which was manned by a crew of three: one for
steering the rudder (Bauer himself) and two for rotating the propeller. The hull had the shape of a rough ship with rect ends and
it was coated with iron sheets. Ballast water was admitted directly into the hull and a sliding weight, which moved horizontally
along the hull's centerline, was used to control the balance of the vessel, as later hydroplanes would do. After a successful
first immersion, in a second attempt the sides of the hull were crushed by underwater pressure and the crewmen narrowly saved
their lives. So, this submersible vessel could never fulfill the purpose of attacking the Danish fleet which blocked the German
With his second "Ictíneo" (Fish-like), in 1864 Spanish inventor Narcís Monturiol was ahead of his time. Three years before he had
built his first "Ictíneo", which used manual propulsion. The new vessel had a double hull of modern shape, built of wood and coated
externally with copper sheets; the ballast tanks located between both hulls could be pumped out by means of compressed air.
Propulsion was made through a steam engine, even during immersion, when oxygen provided by a special device replaced the
atmospheric air. The oxygen was stored in tanks and used as well for crew's breathing and for the internal lighting. The hull had
portholes in the small turret, in the sides and in the bow. The purpose of this submarine was the harvesting of coral under safer
conditions, but financial problems led to the scraping of this remarkable vessel in 1868.
The submersible vessel in the American Civil War
During the American Civil War, the Confederate States were facing the blockade imposed by the numerically superior Union Navy.
For solving this situation their engineers resorted to unorthodox ideas such as the coarse armored ship CSS Virginia or the
submersible boats presented in this article. The CSS David was the first submersible boat deployed in war actions as well as the
first one propelled by a steam engine. This vessel was capable of navigating with the hull wholly submerged, protruding from
the surface only the funnel and the small superstructure. However, steam propulsion had the obvious drawback of a clearly visible
The armament, and explosive charge attached to a long pole fixed to the prow of the vessel, was not wisely designed, as it
potentially caused severe damage to the attacking boat as well. The capsule contained 60 kilograms of powder and a chemical
detonator triggered by impact. The 5th October 1863 the CSS David attacked the ironclad USS Ironsides with this explosive charge,
opening a large breach on her hull which however was insufficient to sink the ship. On the other hand, the small submersible
took the worst part, as the explosion fatally damaged the vessel and the largest part of the crew died.
One year later a new submersible boat, designed by Horace L. Hunley, was ready for trials. This nefarious contraption sank twice
during the trials, causing the death of the largest part of the occupants, including Hunley. Once retrieved from the waters, the
vessel was named after her infortunate creator. The CSS Hunley was propelled by the manual force applied by eight men; despite
being slower, the new submersible would be at least more discrete and also smaller. The watertight metallic hull was designed for
allowing a full immersion and two hydroplanes located in the prow allowed underwater diving and climbing. Oxygen inside the hull
could last for two or three hours and the effort of manually propelling the boat greatly contributed to its rapid consumption.
The tragedy of the CSS David led to the adoption of a new attack method in which the explosive charge was not detonated by
impact. The charge had to be placed on the target vessel and then detonated from a safe distance by means of a cable. The 17th
February 1864 the CSS Hunley became the first submersible boat which managed to sink a surface ship: the steam-powered
sloop-of-war USS Housatonic. However, this victory was tarnished by fatality as well, as the CSS Hunley was sunk as well and her
whole crew perished; for some reason, the infortunate vessel was too close when the charge exploded. When after some years the
remains of the USS Housatonic were examined, the CSS Hunley was found lying on the seabed with nine skeletons inside.
The USS Intelligent Whale was the Yankee response to the CSS David, first submersible vessel launched by the Confederate. This
experimental vessel, manually propelled like the CSS Hunley, was hardly maneuverable and lacked an effective armament. Because of
this, but mainly due to legal issues, she did not take part in any military action during the war. Immersion was achieved by
filling water compartments, which for emersion had to be emptied by means of manual pumps or compressed air. It was estimated
that the crew - a minimum of six for operating the vessel - could stay submerged for about ten hours.
During the only known trial, held in 1872 and reported by submarine pioneer John Philip Holland, two men commanded by a certain
General Sweeney submerged the boat in 16 feet of water; then, wearing a diver's suit, Sweeney emerged through a hatch in the
bottom of the hull to place an explosive charge under a scow. After returning to the submersible boat, the charge was exploded by
means of a lanyard and a friction primer. This procedure required that, once reaching the target area, two anchors were released to
keep the submersible boat in place. Then, compressed air had to be released until the pressure inside the hull were higher than
outer's water pressure; this allowed to open the floor hatch without permitting water to enter.