the water. They were aided in their breathing by the hollow
papyrus reeds. There are also records of the city state of Athens having
used divers to clear the entrance to their harbor during the siege of
Syracuse. Even Alexander the Great was aware of the possibility of
submarine defenses and took it into account during his battle with Tyre. He
employed divers to clear up possible underwater defenses. Of course all
these records in ancient history do not talk about any real and operating
submarine. Yet, it is mentioned that he went down for inspection in Tyre in
a vehicle that kept its occupants dry and could be seen through. (The Saga
of the Submarine: Early Years to the Beginning of Nuclear Power)
The modern version of the submarine was first started on by William
Bourne in 1578. This was for the purpose of underwater navigation, and he
had a history in the Navy as a gunner. This was a boat that could be
completely submerged and rowed beneath the surface. This was a boat with a
wooden framework and covered up by the use of waterproof leather. For
submersion, the entire volume of the boat was reduced by using vises for
the contraction of the sides. This was only limited to an experiment. The
same principle was used by Cornelius Van Drebbel in 1620. He was a Dutch
doctor living in England. The power for this "submarine" was also provided
by the rowers. The concerned oars came out from the sides through certain
seals in the hull sealed by leather seals. There were a number of snorkel
air tubes that linked the boat to the surface. This made sure that the boat
could stay under water for quite some time. It is said that this boat
stayed 12 to 15 feet below the surface of the Thames River for several
hours. This was not a single boat, but was followed up by two other boats.
As the models follo...