FIRE CONTROL AND GUNNERY SYSTEMS
A. TORPEDO FIRE CONTROL SYSTEM|
14A7. Description. The torpedo fire control
system employs several electrical devices which
assist in solving fire control problems and firing
the torpedo tubes. The devices that perform
these functions are the torpedo data computer,
the gyro angle indicator regulators, and the
torpedo ready and firing light systems.
The torpedo data computer is located in
the conning tower and is energized by circuit
GA1, having 115-volt alternating current, and
circuit 17GA1, having 115-volt direct current,
through individual double pole, single throw,
fused switches on the I.C. switchboard.
The gyro angle indicator regulators for automatically
setting the gyro angles on the torpedoes in the tubes
are located at the forward
and after tube nests and are controlled by separate
fire control circuits from the torpedo data
computer. The regulators are supplied with 115-volt
direct current through circuit 17GA3 which
is energized through a double pole, single throw
switch on the forward auxiliary power switchboard
in the control room, and circuit 17GA4
which employs a similar switch on the after
auxiliary power switchboard located in the
maneuvering room. Sixty-ampere fuses, in special
fuse boxes, are included in each circuit.
The following circuits are provided in addition
to those mentioned above:
1. A Pitometer log repeater circuit to the
torpedo data computer from a rotary transfer
switch on the action cutout switchboard.
2. A gyrocompass repeater circuit to the
torpedo data computer from the gyrocompass
14A2. Operation. Detailed operating procedures are
given in Bureau of Ordnance publications and the
manufacturer's instruction pamphlets.
B. TORPEDO READY LIGHT, TORPEDO FIRING, AND|
BATTLE ORDER SYSTEMS
14B1. General description. The torpedo
ready light and torpedo firing systems perform
several important functions: They provide a
means 1) of informing the fire control party
when the tube is ready to fire, 2) of directing
the tube crew to stand by a tube to fire, 3) of
firing the torpedoes remotely from the conning
tower and simultaneously indicating to the tube
crew by means of an audible and visual signal
that the tube has been fired, and 4) of indicating
by a visual signal in the conning tower that the
tube has fired. They also indicate, by means of
a visual signal to the fire control party in the
conning tower, that the gyro angle indicator
regulators are matched.
14B2. Torpedo ready light and battle order
system. This system, circuit 6R, is energized
from the 120-volt direct current bus on the I.C.
switchboard through a fused double pole, single
throw supply switch labeled 6R. Forward and
after transmitters in the conning tower are used
to transmit torpedo orders to an indicator at
each tube nest. When power is turned on in the
conning tower, the GYRO SPINDLE and
READY pilot lights in the transmitter, the
READY AT TUBE, and the STANDBY pilot
lights in the corresponding indicator in the torpedo
room are lighted. When the gyro retraction spindle
switch contacts are closed, an amber
GYRO SPINDLE IN light in the indicator in
the conning tower for that tube is lighted. When
the tube interlock switch contacts are closed,
the amber READY AT TUBE light for that
tube in the indicator in the torpedo room is
lighted. When the operator turns the indicator
switch for that tube, it lights a green READY
light for the tube in the transmitter in the
Figure 14-1. DIAGRAM FLEET TYPE SUBMARINE READY LIGHT AN FIRING CIRCUITS,
FOR TORPEDO TUBE 7 ONLY.
conning tower. When the gyro mechanism of the
tube nest is matched upon closing the manual
contact of the gyro setting mechanism contact
maker, a red ANGLE SET light in the transmitter
in the conning tower is lighted. When a
particular tube standby switch in the conning
tower is turned to STANDBY at the transmitter,
the corresponding green STANDBY light
for that tube in the indicator in the torpedo
room is lighted. When the firing contact maker
is pressed, the tube is fired through operation
of the pilot valve solenoid; a red FIRE light in
the indicator is lighted and a buzzer is operated
at the tube nest.
14B3. Torpedo firing system. The torpedo
firing system, circuit 6PA, is energized from the
120-volt direct current bus on the I.C. switchboard
through a fused double pole, single throw
supply switch labeled 6PA.
Separate fixed and portable contact makers
or firing keys, for independently controlling the
forward and after groups of firing solenoids, are
located at the torpedo ready light and firing
panels in the conning tower. A key mounted on
the gyro angle regulator indicators operates a
light on this panel to show that the regulator
Firing circuits are interrupted through
Figure 14-2. Conning tower torpedo firing panel.
Figure 14-3. Torpedo room ready light and ready
Figure 14-4. Torpedo tube interlock switch and pilot
Figure 14-5. Spindle switch on torpedo tube gyro
switches on the torpedo ready light and firing
panel and through local interlock switches at
each torpedo-tube as shown in the wiring diagram,
Figure 14-1, which is complete for one
Figure 14-6. Gyro angle regulating indicator with
right handgrip turned to show trigger switch.
14B4. Operation. A full description of the
method of operation is given in Bureau of Ordnance
publications and in the manufacturer's
instruction pamphlets. They should be consulted
C. TARGET DESIGNATION SYSTEM|
14C1. General. The target designation system is used
for the purpose of transmitting and
indicating the bearing of the target from the
bridge or radar to the torpedo data computer
(TDC) and the 2 plotting stations. It is a simple
selsyn-operated system using manually operated
bearing transmitters on the bridge and an
automatic transmitter coupled to the train
mechanism of the radar. The indicators at the
plotting stations show the true as well as the
relative bearing. A buzzer system with hand
contactors at the transmitting stations and
buzzers at the plotting stations, radar, and TDC
is provided for indicating when the transmitter
is on the bearing of the target. A set of rotary
cutout switches is located at the TDC so that
the operator may shift the bearing indicators to
the transmitter that is to furnish the bearings.
The circuit designation is GT. It is energized
from the a.c. bus by a fused switch on the I.C.
switchboard. Own course input for the indicators
that show the true as well as the relative
bearing is obtained from the gyrocompass repeater
panel through a rotary switch.
14C2. Target bearing transmitter. This
instrument consists of 2 permanently mounted
peloruses on the bridge. One is located at each
end of the bridge. Each pelorus has a pair of
watertight and pressure-proof binoculars of the
high light transmission type. An illuminating
system is built into them to make the cross
wires visible when the instrument is used at
night. The pelorus can be rotated through 360
degrees in azimuth and is equipped with a scale
so that the operator may read the bearing at
which the instrument is set. A selsyn generator
inside the pressure-proof case of the instrument
transmits the bearing of the target when the
pelorus is pointed at it. The hand contactor for
the buzzer system is built into one of the training
14C3. Target bearing indicators. These instruments,
when energized and connected to a
transmitter, indicate the bearing as transmitted
by the target bearing transmitters. Their construction
is similar to any other simple selsyn
indicating device. The type installed at the plotting
stations in the conning tower and in the
control room indicate the true as well as the
relative bearing by means of a second dial which
receives from the gyro system and indicates own
course. The type used at the TDC shows the
relative bearing only, but utilizes 2 dials, coarse
and fine, so that increased accuracy is gained.
An additional indicator showing both the true
and the relative bearing is located at the radar
to aid in coaching the operator of this latter
instrument on the bearing of the target. This is
a coarse reading instrument, its dial being graduated
in 5-degree increments. Selector switches
are provided at the TDC so that various indicators
may be switched to the transmitter that
is to furnish the bearing.
14C4. Operation. Full instructions for the
operation of this system are contained in
publications of the Gunnery Department of the
Submarine School and in manufacturer's instruction
14C5. Maintenance. Maintenance of the target
designation system is identical with that of
any other system containing selsyn instruments.
Special care must be taken in sealing the target
bearing transmitters to insure that the watertight
joints and the cable packing glands are
carefully made up in order to prevent flooding
and consequent disabling of the instrument.
14C6. New installations. The latest design
installations have, in addition to the units
described above, additional transmitters operated
by the sound gear and the periscopes for the
transmission of both bearing and range to the
stations equipped with indicators. In addition,
an improved model of the target bearing transmitter
is provided with an own course dial energized from
the gyro repeater panel so that the
true as well as the relative bearing may be read
at the instrument. The ship's plans should be
consulted for details.
A center section containing three 2-dial
bearing indicators, and a range indicator with
selector switches so that the bearing may be received
from the target bearing transmitters on
the bridge, the periscopes, radar, or the sonar
system has been added to the TDC. A range in
Figure 14-7. Schematic diagram of target designation system.
Figure 14-8. Target bearing transmitter, Mark 8.
Figure 14-9. Target bearing indicator, type installed
Figure 14-10. Target bearing indicator, type installed
At plotting stations.
Figure 14-11. Target bearing indicator, type installed
Figure 14-12. Bearing Indicator and bearing indicator
selector switches installed at TDC.
Figure 14-13. True bearing and range indicator at
plotting stations, newest installations.
dicator for receiving range either from the radar
or from the sonar system is also provided.
Auxiliary pointers, mechanically controlled by
movement of the TDC input dials for bearing
and range, are provided so that the indicated
values of relative bearing and range may be
introduced into the TDC simply by matching
the pointers with the value indicated.
D. TORPEDO BATTERY CHARGING AND HYDROGEN BURNING SYSTEMS|
14D1. Torpedo battery charging system.
The battery charging circuits are brought to
indicating panels and receptacles located at the
racks and the tubes. The circuits take main battery
voltage, through a rheostat, to outlets from
which connections may be made by portable
cables to charge torpedo batteries either when
the torpedoes are in the tubes or when they
are in the racks. Ammeters are provided in the
The arrangement of outlets for the charging circuits
varies from ship to ship, but in general, individual
units are identical.
Supply switches are usually located at the
forward torpedo room auxiliary power panel
and the maneuvering room auxiliary power
14D2. Torpedo hydrogen burning system.
The battery compartment of each torpedo is
equipped with 3 hydrogen burners located
directly under the inspection plates. Each burner
is constructed of a small coil of resistance wire
mounted in a copper mesh casing. The coil of
resistance wire reaches a temperature sufficiently
high to ignite any hydrogen gas that may be
generated by the batteries.
Power supply to the burning units is provided
by control panels located in each torpedo
room. They have a sufficient number of outlets
to accommodate all torpedoes in the tubes and
on the racks. Each burner is supplied with a.c.
from the I.C. switchboard through a transformer
in the control panel. Each outlet is controlled
by a switch, and the current to each burner can
be read on an ammeter through a selector
switch. A line level compensator is provided in
the panel to keep the current to each torpedo
at 4.75 amperes. Fine adjustments for individual
circuits may be made by adjusting a resistor provided
for each outlet.
Figure 14-14. Schematic diagram of torpedo battery charging controller.
Figure 14-15. Schematic diagram of hydrogen burning circuit.
Figure 14-16. Electric torpedo battery charging panel.
Figure 14-17. Electric torpedo hydrogen burning
Copyright © 2004 Historic Naval Ships Association
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Version 1.10, 22 Oct 04