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Combat Information Center DOctober rine (Radar Plot)

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Radar Equipment

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The Combat Information Center is maintained as a source of accurate up-to-the-minute informa­tion on own and enemy surface and air units and on navigational objects.
Its primary purpose is to supply this information to flag, ship and gun­nery control stations to further the fighting effici­ency and safety of the ship.
The information transmitted from CIC is obtained from surface, air and tactical plots.
The data for these plots are obtained from radar equipments, visual re­ports from stations in own ship, communications from other ships in company and aircraft, charts, etc.
The officer of the deck is responsible for passing on to the CIC all information of the situa­tion which is of interest to CIC.
The CIC watch officer will however ensure that he is in close touch with the situation and take all steps necessary to acquaint himself of the existing situation.


The CIC is capable of maintaining simultaneous plots of surface and air attacks, a tactical plot on a DRT and a fighter director intercept plot.
Information on the relative bearing, range, size and composition of own forces and air and surface targets is transmitted to the gunnery control sta­tions over battle telephones.
No attempt is made to designate targets but rather, to keep the con­trol officers constantly informed of the general situation and to coach directors onto targets.
Flag and ship control stations are informed by JS battle telephone of the true bearings, distance and size and disposition of own forces, of air and surface targets and navigational objects.
The 24MC talk­back circuit is used for intercommunication be­tween Flag, Conn, and CIC.
The 20MC talk-back system is used for emergency transmission from CIC.
No other station is authorized to initiate transmissions over this system.
Stations on the 20MC system are : Conn, Fire Control, Flag Plot, Air Defense, Air Defense Aft, Damage Control, Shout Forward and Radio One.
Stations on the JS battle telephone circuit are : Conn, Fire Con­trol, Flag Plot, Flag Conn, Batt II, Air Defense, Air Defense Aft, Radio One, Combat Aft, Shout Forward, Main Plot, Secondary Plot and Damage Control.
Remote PPI's which enable the observer to select the PPI indication from any of the search radar equipments are located at Combat, Conn, Flag Plot, Flag Conn, Fire Control, Air Defense, Chart House, Main Plot, Batt II and Combat Aft.


The surface plot is a relative movement plot on a vertical board of all surface contacts, own as well as enemy forces, using true coordinates with own ship at the center of the plot.
The information from which this plot is derived is supplied by an SG radar equipment whose antenna is located on the mainmast structure, supplement­ed by information from the SG radar equipment located on the foremast and from fire control radar equipments.
The control and indicator for the forward SG equipment is installed in Flag Plot.
The plotter on the surface plot is in com­munication with the radar operator by means of battle telephones.
Ordinarily, the stop-sweep method of obtaining information on bearing and range is used by the SG radar operators.
This method requires that the sweep be stopped for not more than five sec­onds.
During this interval the radar operator stops the sweep, brings it over the target on the PPI by hand and notes the true bearing on the bearing indicator.
While he is obtaining this in­formation, the assistant operator has brought the ranging step to the target and has obtained the range.
The radar operator starts the sweep as soon as he has obtained the bearing.
He then transmits this bearing and range (which he ob­tains from an illuminated counter) to the surface and tactical plots by battle telephone.
The information plotted on the surface plot is evaluated and filtered by the Surface Plot Officer whose duty it is to supervise transmission of data from the radar scopes to the plot making sure that the plotter maintains his plot correctly and up to date.
This officer shall be an expert at evaluation of the information presented on the radar scopes as well as a proficient operator of the radar equip­ment.
The information displayed on the Surface Plot is transmitted to the' Main and Secondary Bat­teries by two officer talkers.
These officers are representatives of the two batteries and are re­sponsible for providing all data to the gunnery control stations.
Relative bearing will be used on both the Main and Secondary Battery circuits.


The air plot is a relative movement plot on a vertical board of all aircraft contacts, both own and enemy, using true coordinates with own ship at the center of the plot.
The information from which this plot is derived is supplied by the SK radar equipment whose antenna is on the foremast structure.
The control and indicator for this equipment is installed in CIC.
The plotters are in communication with the radar operator by means of battle telephone.
The stop-sweep method of obtaining informa­tion is not used on the SK radar equipment.
Con­tinuous sweep is done and the bearing and ranges are obtained from the PPI.
This is made possible by means of the bearing index line on the mask and the range circles.
If a more accurate range is desired, the measuring step is brought to the pip on the A-scope without stopping the sweep.
This latter operation is possible because of the relatively long duration of the pip on the scopes of this equipment.
The information plotted on the air plot is eval­uated and filtered by the Air Plot Officer.
His duties and capabilities shall be similar to those of the Surface Plot Officer.
The information dis­played on the Air Plot is transmitted to the Sec­ondary Battery by the officer mentioned in disc­ussing the Surface Plot. Only relative bearings are used.


The tactical plot is maintained on a battleship-type dead reckoning tracer.
On it are plotted contact reports, visual contacts, radar contacts, distribution of own forces and all other pertinent data.
Sources of information for this plot are radio and visual reports, radar and optical bear­ings and ranges.
It gives a true picture of the current and past situation for 'responsible officers over view.
The plotter wears an outlet of the SG radar information circuit.
From this information, con­tinuously plotted, the course, speed and probable movement of enemy forces can be determined.


The fighter director plot is a vertical plot on thrue coordinates with own ship at the center.
Information on the raids to be intercepted and own fighters are received from the SK radar equipment by battle telephone.
This information is plotted on the FD board by an assistant to the fighter director officer.
The latter transmits the necessary orders to the fighters for making the interception, using the procedure laid down in CSP 1291A.

The summary plot is a horizontal plot on which information concerning disposition of ships in own formation, short range air targets, etc., are plotted. The plotter who is maintaining this plot also observes a PPI and keeps the CIC officer informed of any change in the disposition of own forces.


The CIC Officer is in general charge of CIC and is responsible for the information disseminated from it.
He must be an expert at evaluating the information appearing on the radar scopes and in order to accomplish this important duty he must be able to circulate between the radar equip­ments and the plots.
The CIC Officer by means of battle telephones has access through a selector switch to all the important gunnery and ship con­trol circuits. He is responsible for the transmis­sions over the 20MC.
The JS circuit is used to disseminate informa­tion from CIC throughout the ship.
The talker on this important circuit should be a radarman thoroughly familiar with all phases of the CIC organization etc., and a capable talker.
Under the supervision of the CIC Officer, he will transmit the information from C1C.
The Flag Officer's representative on the JF circuit will be paralleling this information to some extent.


The auxiliary C1C is located in the Main Bat­tery Plotting Room.
Air and surface relative plots and a DRT plot of the same data in use in CIC are maintained here under the supervision of the Auxiliary CIC Officer.
Its source of information at this time may be limited to other ships of the formation due to damage to own radar equip­ments.


When dOctober rine or orders require this ship to pass to other ships information of radar contacts, the transmissions are made in CIC.
If the use of TBS is authorized, CIC will initiate reports of contacts over this circuit.
The CIC Officer is responsible that these reports are encoded in the proper voice code and that the proper voice pro­cedure is used.
If TBS silence is in effect, the report of a contact is made by visual means.
The proper general signal is prepared in C1C and de­spatched to the signal bridge by messenger where it is sent out without further orders.
The CIC Officer is responsible for the correct form of this signal.
In all cases of transmissions originating in the CIC the Captain will be informed that they have been made.


The radar equipments in CIC are of great value to the Navigator when operated properly.
Bear­ings and distances to land masses, and under cer­tain conditions to beacons and light houses, can be obtained by the SG and FH radars. In close waters during darkness or low visibility, such information is very important and is transmitted by battle telephone to the Navigator upon request.
Under such conditions a chart of the area will be kept on the tactical plot and will be used by the CIC Officer to keep informed of the ship's position.
Photos & text courtesy of Pieter Bakels.

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