SONAR CONTROL ROOM (SCR)

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HAIDA'S  Sonar Control Room as it appeared  in September, 2007. It  would have been staffed by four operators. (Photo by Jerry Proc) 
The Sonar Control Room contains the control equipment and indicators for various sonars that were carried in the ship. Sonar is an acronym for Sound Navigation and Ranging. Prior to this term, the Canadian, British and Commonwealth Navies used the term ASDIC in reference to the Anti-Submarine Investigation Committee of 1917. HAIDA was fitted with various submarine detection equipment over the years , but at the end of her service life she was fitted with the following sets:

AN/SQS-10 Search Sonar (6,000 yards when echo  ranging under perfect conditions)
AN/SQS-501 Sea Bottom Identification Set  (Detection Dept 1,800 feet)
147F Depth Finding Set. Used in conjunction with 164B set (max detection depth is 1,500 feet)
164B Range and Bearing Finding Set for Ahead Throwing Weapons (Range 2,500 yards)

The Sonar transmitting and receiving equipment was located in the Sonar Instrument Space in the Forward Lower Messdeck. Mounted on the bottom of the hull was the sonar dome which housed the transducers. This dome could be retracted when the Sonar was not being used. SONAR could not be used if the ship was going faster than 15 knoths otherwise the flow of the water across the dome would hinder the reception of echoes.
 
 

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Equipment ID in this photo:

1) Dome locator. It has  three indicator lights: up--moving--down.
2) Gyro repeater.
3) 164B Bearing Recorder. It also sent a signal to a readout in the wheel house. When the bridge gave the order "steer by sonar", the helmsman would follow the sonar bearing  repeater.
4) Operator Position. By turning the knob to a new bearing,  the transducer will follow to the new bearing. By pressing the knob, the sonar set transmits a single pulse. 
5) 164B Range Recorder.
6) 164B Down Angle Recorder. 
7) Barometer. It does not belong in the SCR and was placed there only to cover up a bunch of cut cable ends. 

Three, small, circular gauges mounted to the plywood bulkhead do not belong there. These are pressure gauges and were  mounted for a movie shoot. They have never been taken down.

The AN/SQS-10 operator's console would have been at the left side of the Sonar Control Room. HAIDA does not have an example of it. There was also a repeater for it above the VK5 slave PPI in the Operations Room. .

The AN/SQS-501 recorder is mounted on the starboard bulkhead in the Operations Room. 

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This SONAR dome, known  as “HULL OUTFIT #7A” was part of HAIDA’s SONAR system and would be found under the hull about one third the length of the ship. All the SONAR transducers were mounted within the hull outfit.  The exterior of the Hull Outfit is clad with a special type of stainless steel called Staybrite. Normally, the dome is retracted when the ship is in shallow water or in harbour. When SONAR is to be used, the dome is lowered from its retracted position. It then floods with sea water, thus permitting the passage of the initial transmitted sound pulse and reception of echoes. In the above photo, the hull outfit is being displayed in the inverted position.  (Photo by Jerry Proc)

To hear pinging from a real sonar, select this link  (168 kb wav file). What you are hearing consists of a transmission, followed by an echo after 3 seconds. This is repeated a second time. It therefore takes 1.5 seconds for the sound to reach the target. The returning echo after 3 seconds corresponds to a contact approximately 2,400 yards away (Calculation: The speed of sound in water is approximately 4,800 feet per second  multiplied by 1.5 seconds = 7,200 feet or 2,400 yards). File courtesy of Keith Wilbur.
 

Reference: http://www.hazegray.org/navhist/canada/systems/sonar/

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Nov 3/13