Navigation Systems and Other Vital Equipment
Prior to carrying out any detailed sea floor investigations with deep towed
instruments, remote controlled Vehicles (ROV) and/or manned submersibles, it is
wise to have a general overview of the landscape in order to choose the most
adequate targets.
In order to navigate towed instruments and manned submersibles on the sea
floor, it is necessary to have a reference frame with respect to the on-site topography. Acoustic transponders, which float on an anchor at only about 200 m high
above the sea floor and have battery-powered sonar and pinger-sets sending an
acoustic signal at different frequencies, are deployed in a triangular network
several miles wide (Fig. 3.1). The transponders will emit and receive sonic pulses
at different frequencies and when coordinated with signals from the submersible
and its surface ship, they will enable precise navigation within a given geographic
network. Any instrument or vessel deployed within such a network can be located
on a geographic grid by the surface ship, which is, in turn, related to the satellite
grid.
Undersea vehicles can carry different kinds of instruments depending on the
goal of exploration. However, navigation systems, sonar, a compass, a load
pressure-gauge and some electronic devices for detecting water infiltration, as well
as devices for measuring oxygen and ambient humidity are critical instruments
which are always carried on board. Devices that enable communication with the
surface ship are also vital instruments that are carried on board manned and
unmanned submersibles.
Early Underwater Exploration
Since antiquity, the sea has always intrigued humankind. When Alexander the
Great was returning from India in the year 325 BC, he camped on a beach on the
coast of Persian Gulf. While there, he decided he wanted to dive into the blue
water to look at the fish. He requested his men to build a wooden barrel so he could
descend about 10 m, from where he was able to see the underwater world through
a window made from the skin of a donkey. The Greek philosopher, Aristotle, who
was a contemporary and teacher of Alexander, described the primitive diving bell
using the Greek term ‘‘corinpha’’ meaning cauldron (Riffaud 1988).
The USA was the first nation to build submersibles to be used for military
purposes during the American Civil War in the 1860’s (Jarry 2003). In 1776,
David Bushnell built a one-man submersible called the Turtle, which look like an
oval egg, or like the two carapaces of giant turtles that had been put together. This
construction was made of wood and capable of diving as deep as 15 m. The Turtle
was powered by the diver’s own hand which turned a tendril, and the Turtle was
also able to carry a charge of explosives. During the War of Independence (1776),
Navigation Systems and Other Vital Equipment
57
Prior to carrying out any detailed sea floor investigations with deep towed
instruments, remote controlled Vehicles (ROV) and/or manned submersibles, it is
wise to have a general overview of the landscape in order to choose the most
adequate targets.
In order to navigate towed instruments and manned submersibles on the sea
floor, it is necessary to have a reference frame with respect to the on-site topography. Acoustic transponders, which float on an anchor at only about 200 m high
above the sea floor and have battery-powered sonar and pinger-sets sending an
acoustic signal at different frequencies, are deployed in a triangular network
several miles wide (Fig. 3.1). The transponders will emit and receive sonic pulses
at different frequencies and when coordinated with signals from the submersible
and its surface ship, they will enable precise navigation within a given geographic
network. Any instrument or vessel deployed within such a network can be located
on a geographic grid by the surface ship, which is, in turn, related to the satellite
grid.
Undersea vehicles can carry different kinds of instruments depending on the
goal of exploration. However, navigation systems, sonar, a compass, a load
pressure-gauge and some electronic devices for detecting water infiltration, as well
as devices for measuring oxygen and ambient humidity are critical instruments
which are always carried on board. Devices that enable communication with the
surface ship are also vital instruments that are carried on board manned and
unmanned submersibles.
Early Underwater Exploration
Since antiquity, the sea has always intrigued humankind. When Alexander the
Great was returning from India in the year 325 BC, he camped on a beach on the
coast of Persian Gulf. While there, he decided he wanted to dive into the blue
water to look at the fish. He requested his men to build a wooden barrel so he could
descend about 10 m, from where he was able to see the underwater world through
a window made from the skin of a donkey. The Greek philosopher, Aristotle, who
was a contemporary and teacher of Alexander, described the primitive diving bell
using the Greek term ‘‘corinpha’’ meaning cauldron (Riffaud 1988).
The USA was the first nation to build submersibles to be used for military
purposes during the American Civil War in the 1860’s (Jarry 2003). In 1776,
David Bushnell built a one-man submersible called the Turtle, which look like an
oval egg, or like the two carapaces of giant turtles that had been put together. This
construction was made of wood and capable of diving as deep as 15 m. The Turtle
was powered by the diver’s own hand which turned a tendril, and the Turtle was
also able to carry a charge of explosives. During the War of Independence (1776),
Navigation Systems and Other Vital Equipment
57