The Control Room is the center of the submarine, both physically and operationally.
Find the panel of red and green lights on the port, or left, side of the room. This is the Hull Opening Indicator Panel, nick-named the Christmas tree. Each hatch, ballast tank vent, engine vent or exhaust, and other opening to the sea on the boat has a red light to indicate that it is open, and a green light to indicate it is shut. The boat is not safe to dive until all the lights are green. Even then, a little compressed air is let into the boat and a barometer checked to make sure that the pressure increases before diving. Only then are the hydraulic controls used to open the vents on the top of the main ballast tanks. This allows air to escape through the vents, and seawater to enter through the flood ports in the bottom of the tanks. As the tanks flood, the boat submerges. One of the tanks near the center of the boat, the Negative Tank is adjusted to bring the submarine to neutral buoyancy under water. The variable ballast tanks forward and aft can be adjusted to balance the boat. A boat is in good "trim" when it can stop its motors and hang at about the same depth and angle.
Controlling the depth and angle of the submarine was critical. She was designed to be operated at a test depth of 412 feet, and she was expected to survive without being crushed up to 600 feet. During combat at least some Balao class submarines survived depths in excess of 800 feet.
Once the boat submerges there are constant changes in the density of the water around the boat as well as movement of men and fluids in the boat all of which effect its depth and angle (also called "angle on the boat" or "bubble".) There are two methods that are used to control the depth and angle. First large changes are achieved using the trim and drain system. This system allows water to be moved between variable ballast tanks forward or aft. This works well for big changes, but is slower and noisier than the second method which uses bow and stern planes. As long as the boat is moving, large bow and stern planes are used to "fly" through the water just like the control surfaces on an airplane. The diving station has depth gauges and a bubble inclinometer (like a carpenter's level) to indicate the depth and angle on the boat. Separate operators use the dive plane control wheels to adjust the angle of the bow and stern planes. The stern planes are used primarily to keep the boat level and the bow planes primarily to control depth.
Incorrect operation of the dive planes, hydraulically controlled ballast tank vents, or air pressure manifolds could lead within seconds to an uncontrolled dive beyond the crush depth, or accidental surfacing and exposure to the enemy.
The unforgiving nature of submarines required a highly skilled crew. Even after volunteering for this dangerous duty, selection for his skills, and advanced shoreside training, a sailor was not truly a submariner until he had qualified on his boat. To qualify, each sailor was required to study every piece of equipment on the boat, know the function of every valve and switch, and to have demonstrated his competence operating the equipment to the Chief on the Boat and qualifications officer. Only by qualifying did he earn the right to wear the submarine dolphin insignia.
To the left of the ladder to the conning tower are the boat's alarms. The
green alarm is the klaxon
or diving alarm. When that sounded, the crew had less than 10 seconds
to get below decks, secure all hatches, and begin the dive. The boat would
be at 65 feet in about 35 seconds. The yellow alarm is for general
When it sounded, the men raced to their battle stations and prepared
for combat. The red alarm is the collision alarm
which has been compared
to a ship screaming in fright. When it sounds, all the watertight doors and bulkhead flappers
are instantly shut.
Below this compartment is the pump room, and above it, in a separate water tight compartment, is the conning tower.
See more views in the Control Room port side aft, or forward.
Other Features in this Compartment:
Air Manifolds and Gauges: Located aft and starboard, or on your right as you entered from the galley, these manifolds controlled the flow of air throughout the boat. They are located from aft to forward in the following order.
- The Low Pressure Air Manifold is used to control the delivery of 10 lb. air to finish emptying the ballast tanks after surfacing. The air is supplied from its own blower in the pump room.
- The 600-lb. Main Ballast Tank Air Manifold is used to control the delivery of air into the main ballast tanks.
- The High Pressure Air Manifold is used to control the flow of 3,000 lb. air to and from the storage tanks, from the air compressors and to the 3,000 lb, 600-lb, 225-lb and torpedo air manifolds.
- The 225-lb Air Manifold supplies air for all the low pressure equipment and some of the tanks used only near the surface. For example, it is used to blow variable ballast tanks and also to put some pressure in them to assist the Trim Pump in moving salt water to sea at greater than periscope depth.
Gyrocompass Control Panel: Located forward of the air manifolds on the starboard side. This contains the electronics needed to operate the master gyro compass, and the controls to distribute its output wherever it is needed. The Master Gyrocompass binnacle is located in the center of the control room under the chart table next to the dead reckoning table. The Arma Mk 7 gyrocompass was one of the most accurate compasses created during World War II. This was a critical part of the system that aimed the torpedoes as well as being needed to navigate the ship.
Interior Communications (I.C.) Switchboard: Located forward of the gyrocompass control panel on the starboard side. The interior communication systems in a submarine provide the means of maintaining contact, transmitting orders, and relaying indications of the conditions of machinery to other parts of the ship. The power for almost all of these systems is distributed through this switchboard. It includes 120 VAC, 120 VDC, 6 VAC, and several action cutouts for alarms, and log systems.
Forward Auxiliary Switchboard: Located forward of the I.C. Switchboard on the starboard side. This supplies 250 VDC to the many auxiliary motors in the forward half of the submarine. The auxiliary motors operate compressors, pumps, heaters, blowers and other high power equipment. It is supplied by the forward battery, auxiliary engine, or through a bus tie from the after battery.
SV Radar Equipment: The SV radar amplifier/receiver as well as its power supplies are located just forward of the entrance to the radio room. Its indicators and more power supplies and controls are located on the other side of the periscope wells, across from the trim and drain manifold. This is an improved air search radar installed in 1945.
General Announcing Equipment: The General Announcing system is comprised
of two voice communication circuits, one-way (1MC) and two-way (7MC). The
amplifier stack is located across from the air manifolds forward of the
SV radar equipment.
ST Radar Equipment: Just forward of the General Announcing Stack is the receiver/amplifier for the ST range finding radar. Its outputs are displayed on the SJ indicators in the conning tower.
Periscope Wells: The housings for the periscopes when they were
in their lowered positions are located along the center line aft of the
master gyro compass. Numerous bits of equipment are attached to them, for example; the Auxiliary Gyro Control Panel, lighting switchboard, sound powered phones switchboard, Identification Friend or Foe (IFF) gear, radar gear, and alarms.
Dead Reckoning Tracer (DRT): Located in the center of the compartment,
this device was used to mechanically plot a dead reckoning (estimated)
position. Input was fed into the unit by the dead reckoning analyzer indicator
(located to port of the forward watertight door) which receives data from
the underwater log (in the forward torpedo room) and master gyrocompass. Or, it could be operated
by hand at its forward panel. The unit now contains a chart of Pampanito's
Bathythermograph: Above the master gyrocompass is the bathythermograph
which measured the temperature of the water at various depths outside the submarine with
a sensor located on the starboard side of the conning tower. This system
detected thermoclines (cold layers) in the water under which the sub could
slip to deflect enemy sonar.
Fathometer: Also located above the gyrocompass is the fathometer indicator
which displayed the results of electronic pings bounced off the bottom to determine the depth of water below the keel.
Trim Manifold: The trim pump manifold is located in the after
port side corner. This manifold is used to pump water from and to the sea as well as from one trim tank to another inside of the pressure hull. The crew uses this to maintain "neutral buoyancy" where the submarine's weight is matched exactly by the weight of the water being displaced, and then "fore-and-aft" trim so the boat operated at ordered depth with minimum use of the diving planes.
Diving Control Station: The diving control station is located at
the center of the port side, just forward of the Trim Manifold. It provides controls for bow and stern
plane tilting, and bow plane rigging. They were operated by hydraulics
or by hand during silent running. Diving and surfacing
operations are discussed in another section. The related equipment in this
Control wheels for dive planes
Shallow (depth to keel) depth gauge
Deep depth gauge
Plane angle indicators
Barometer (to indicate pressure in the the boat)
Main Hydraulic Controls: The main hydraulic
controls in the port side forward corner controlled the many hydraulically
operated units on the boat. Grouped in this area are:
Vent control levers and vent control manifold
Flood control manifold
Hydraulic accumulator charge indicator and air pressure gauge
IMO (hydraulic pump) indicator and switches
Oil supply tank
Gun Access Hatch: The hatch above the safe against the forward
bulkhead leads to the forward gun deck or out to the main deck.
Auxiliary Steering Station: The steering station is located amidships
against the forward bulkhead. Under normal conditions, the steering wheel
in the conning tower was used to control the rudder. This wheel was used
in emergencies. In this area are:
Steering wheel or helm
Underwater log indicator
Rudder angle indicator
Dead reckoning analyzer indicator (lower forward)
Motor order telegraph which transmitted speed orders to the Maneuvering Room where the motors were controlled