before reaching the bottom in order for the vehicle to attain a state of neutral
buoyancy when approaching the sea floor. The weights of the three passengers
inside the sphere of the submersible are also taken into account just prior to diving
for adjusting the total weight of the submersible.
The choice of the diving scientist is usually made according to his special
interest and his qualifications for the target and tasks of a given dive. The person
chosen will be well acquainted with the objectives of the dive and a day or two
earlier, he will begin to prepare himself mentally and physically for this great
adventure. Usually it is recommended to avoid drinking too much liquid the day
before, although there are facilities within the sphere should we need to relieve
ourselves. It is also recommended that the scientific observer get a good night’s
sleep.
Early in the morning, the ship goes on station and positions itself with respect to
the bottom transponder network, which has been deployed on the sea floor earlier
that day. The transponder beacons are laid on the sea floor and mounted with
acoustic devices that send signals of different frequencies to the submersible. The
person responsible for the surface ship’s navigation has the ship pass over each one
of the bottom transponders that were launched a couple hours before diving. The
calibration of the transponder network with respect to satellite data is made, and
the positions are recorded on the computer screen by the navigation team.
Before diving, it is important to check the surface and bottom currents, if any
information is available, and this is another of the roles of the surface ship’s
navigator. Because of underwater or surface water currents, the submersible could
be shunted off from its original target, and sometimes it is necessary to adjust the
trajectory of the submersible while diving. When the bottom navigation system is
ready and calibrated, the captain will inform the chief pilot and the head of the
submarine group that all systems are ready to go and that they will reach the diving
site in 10–20 min.
The submersible’s checklist is done on the deck, with the pilot inside the sphere
and the engineer outside. They communicate with each other about all the vital
points of the submarine. It takes about 40 min to complete this checklist. At this
point, the co-pilot informs the scientific observer that it’s time to go inside the
sphere. Meanwhile, the chief steward has handed the lunch meal to the co-pilot
who is already inside the sphere. Now it is the scientist’s turn to enter the small
sphere in his special red or yellow fireproof jumpsuit. It is also recommended to
wear warm clothes underneath the suit because the outside temperature at the
bottom is only about 1–2 °C at 3,000 m deep in all the world’s oceans. The
ambient temperature inside the sphere will drop progressively as time passes. As
the interior becomes colder, water will start to condense on the interior walls.
When the ship has reached the target area, the captain or the officer on the
bridge will send this information to the submersible group leader, who will tell the
pilot of the submarine to get ready. The pilot will climb up the ladder inside the
sphere and sit on the edge of the hatch. He then verifies the hatch’s seal and cleans
the grooves around the hatch with a rag. This is a common procedure to avoid that
any dust or dirt will prevent proper closing the airtight hatch. The head of the
A Normal Diving Day
71
buoyancy when approaching the sea floor. The weights of the three passengers
inside the sphere of the submersible are also taken into account just prior to diving
for adjusting the total weight of the submersible.
The choice of the diving scientist is usually made according to his special
interest and his qualifications for the target and tasks of a given dive. The person
chosen will be well acquainted with the objectives of the dive and a day or two
earlier, he will begin to prepare himself mentally and physically for this great
adventure. Usually it is recommended to avoid drinking too much liquid the day
before, although there are facilities within the sphere should we need to relieve
ourselves. It is also recommended that the scientific observer get a good night’s
sleep.
Early in the morning, the ship goes on station and positions itself with respect to
the bottom transponder network, which has been deployed on the sea floor earlier
that day. The transponder beacons are laid on the sea floor and mounted with
acoustic devices that send signals of different frequencies to the submersible. The
person responsible for the surface ship’s navigation has the ship pass over each one
of the bottom transponders that were launched a couple hours before diving. The
calibration of the transponder network with respect to satellite data is made, and
the positions are recorded on the computer screen by the navigation team.
Before diving, it is important to check the surface and bottom currents, if any
information is available, and this is another of the roles of the surface ship’s
navigator. Because of underwater or surface water currents, the submersible could
be shunted off from its original target, and sometimes it is necessary to adjust the
trajectory of the submersible while diving. When the bottom navigation system is
ready and calibrated, the captain will inform the chief pilot and the head of the
submarine group that all systems are ready to go and that they will reach the diving
site in 10–20 min.
The submersible’s checklist is done on the deck, with the pilot inside the sphere
and the engineer outside. They communicate with each other about all the vital
points of the submarine. It takes about 40 min to complete this checklist. At this
point, the co-pilot informs the scientific observer that it’s time to go inside the
sphere. Meanwhile, the chief steward has handed the lunch meal to the co-pilot
who is already inside the sphere. Now it is the scientist’s turn to enter the small
sphere in his special red or yellow fireproof jumpsuit. It is also recommended to
wear warm clothes underneath the suit because the outside temperature at the
bottom is only about 1–2 °C at 3,000 m deep in all the world’s oceans. The
ambient temperature inside the sphere will drop progressively as time passes. As
the interior becomes colder, water will start to condense on the interior walls.
When the ship has reached the target area, the captain or the officer on the
bridge will send this information to the submersible group leader, who will tell the
pilot of the submarine to get ready. The pilot will climb up the ladder inside the
sphere and sit on the edge of the hatch. He then verifies the hatch’s seal and cleans
the grooves around the hatch with a rag. This is a common procedure to avoid that
any dust or dirt will prevent proper closing the airtight hatch. The head of the
A Normal Diving Day
71