User Guide

Thermal Layers and the Bathythermograph
In any large body of water, there are layers
where the water is warmer or cooler. The
bathythermograph plots water temperature
against depth to identify the location of these
thermal layers. The benefit of this is that
these layers reflect sound waves, which travel
very well through water, making it more dif-
ficult to locate a submarine using hydrophones or sonar. A submarine
beneath the thermal layer becomes nearly undetectable.
As the submarine descends, the bathythermograph indicates the tempera-
ture at every depth. When the bathythermograph indicates that the
temperature has dropped, this indicates that a thermal layer exists at that
depth. Diving below one of these layers is a good way to escape an enemy
ASW vessel.
Engine-Room Telegraph and Speed Gauge
Control of the submarine’s diesel engines and electric motors is performed in
the engine room. The Captain of the submarine forwards his orders by way of
the engine-room telegraph. The telegraph’s settings indicate the amount of
thrust the engines and motors are set to provide, either forward or reverse.
The speed of the submarine is indicated on the speed gauge and varies based
on sea conditions, damage, and whether the submarine is running submerged
or on the surface. Except at very low speeds, there is no way to come to a rapid
stop. Inertia causes the submarine to continue moving until the drag of the
water causes it to slow to a stop, unless reverse thrust is employed. The num-
ber keys across the top of the keyboard can also be used to control speed:
KEY TELEGRAPH SETTING
0...................................... All Stop
1...................................... Ahead 1/3
2...................................... Ahead 2/3
3...................................... Ahead Standard
4...................................... Ahead Full
5...................................... Ahead Flank
6...................................... Reverse 1/3
7...................................... Reverse 2/3
8...................................... Reverse Full
9...................................... Emergency Reverse
SILENT
HUNTER
26 COMMANDING THE SUBMARINE: Gauges Station
the rate of change in depth. Once under water, with a neutral buoyancy,
the submarine maneuvers to different depths using the bow planes and
motors exclusively unless an emergency occurs where depth must be
gained or lost quickly. The diving planes can be controlled manually using
the “down” arrow key to cause the submarine to dive, the “up” arrow key to
cause a submerged submarine to climb, and the “5” key on the number
keypad to resume a straight and level course
The following keyboard equivalents exist for certain standard maneuvers to
simplify the process of changing depth:
♦
B – Blow tanks; emergency surface at maximum speed using your com-
pressed air reserves in an inefficient manner Note: Using this command
leaves the submarine on the surface with few options since it takes time
to restore the compressed air.
♦
C – Crash dive; the submarine heads for 200 feet at maximum speed and
dive angle.
♦
P – Takes the submarine to periscope depth (65 feet).
♦
R – Takes the submarine to radar depth (45 feet).
♦
S – Surface normally.
Compressed Air Gauge
The number of times the submarine can change depth is dependent on the
supply of compressed air used to force water out of the ballast tanks. This
gauge indicates the amount of compressed air remaining. It is important to
be aware of the status of the submarine’s compressed air supply because
without compressed air the only way to change depth is by using the diving
planes and the electric motors. Once these tanks are empty, they can only
be recharged by sailing on the surface. This process takes an hour or two
depending on the amount of air required. If the submarine finds itself on
the bottom with no compressed air, returning to the surface may be an
impossible feat.
SILENT
HUNTER
25 COMMANDING THE SUBMARINE: Gauges Station