This was the followup class to the St. Laurent class. with certain improvements such as the 3/70 gun forward and the MK 69 fire control director. When first used, these guns had teething problems but they were eventually resolved.

From Haze Gray::

"In the late 1960s, four ships of the Restigouche iclass were refitted to what is known as the Improved RESTIGOUCHE (IRE) class. With IRE, the program replaced the aft 3"/50 gun with an ASROC launcher and the old mast with a new, taller lattice mast. The stern was also altered in order to accommodate a new variable depth sonar. Due to budget ewstraints only four of the Restigiuche class ships received IRE, These were Gatineau, Kootenay, Restigouche and Terra Nova.  The ships that did not receive this refit were paid off into Category "C" Reserve soon afterward, during the manpower shortages of the early- to mid-1970s.

Of these, CHAUDIERE was used as a parts hulk and donated her bow to KOOTENAY after a collision, COLUMBIA became a dockside engineering training platform (with no-thrust wheels replacing her propellers), and ST. CROIX had her weapons and propellers removed and her machinery spaces converted into classrooms.

To summarize, all ships of the Restigouche class were identical on build.

1 x 3" 70 gun  forward
1 x  3" 50 gun aft
2 x  Mk 10 mortar mounts
2 x  Torpedo launcher

As an IRE, the upgrade added Variable Depth Sonar on the aft end.,   The 3"/50 gun was removed and a  ASROC (Anti Submarine Rocket)  system was installed in the place of the 3"/50  gun. One mortar mount was removed and the foremast upgraded.

Here, Kootenay 268 is representing the Restigouche class. Click on image to enlarge. (Via Wikipedia)

The source of the radio antenna drawings  cannot be ascertained at this time. The information  contained within those drawings may not be  100% accurate. .

	257 class as built antennas -  side view.  1 of 2, Click on image to enlarge.  (RCN student handout)    Items of interest: ,  1) AT-150 and AS-390 are UHF comm antennas 2) Chaudiere and other ships in the Restigouche class had UPD-501.
	257 class as built antennas. Aft view.  2 of 2. Click on image to enlarge. (RCN student handout) , Items of interest:  1) The replacement HF DFantenna atop the foremast is the AN/SRD-501 2) AT-150 and  AS-390 are UHF comm antennas 3) Loran is Loran 'A'
	257 class AFTER  conversion  Click on image to enlarge. (RCN student handout) Configuration applicable to: HMCS  Terra Nova, Restigouche, Kootenay, and Gatineau.
	257 class  AFTER conversion.  Click on image to enlarge. (RCN student handout)  Applicable to: Terra Nova, Restigouche, Kootenay, and Gatineau.
	257 class comm antennas Click on image to enlarge. Part of the diagram on the right side is missing. (RCN student handout) Items of interest:  1) AS-1018 . Common mode (Common Antenna Working) UHF antenna. Permits nine UHF radio channels to operate simultaneously. .

 

HMCS Gatineau No 2 deck plan  showing the radios. Click on image to enlarge.  Deck plan provided by Darren Scannell )

 

VARIENCES:

1) Chaudiere and the other ships in her class had the AN/UPD-501 circa 1959
2) Chaudiere had the Underwaer Telephone.
3) Chaudiere had a piano in the cafeteria when she was commissioned.

Jim Brewer, a former RCN Fire Control Technician, served aboard CHAUDIERE  He describes the Fire Control system used aboard that ship.
 

FIRE CONTROL

"There were two Mk 69 Fire Control systems installed. There was the Forward Mk 69 system while the aft was called the Gunar MK 64 system . There were two  AN/SPG 48 radars, one for each fire control system.. The forward system had a director aft of the bridge with the radar antenna atop the director. The aft system had the antenna on the front of the 3"50 gun. Both systems had the Gunar analog computer but there were  different settings depending on the speed of the projectile.  The muzzle velocity of the 3"/70 gun was over 3,000 ft per second  and the 3"50  was about 2,750 ft per second. There was built in wiring so the forward system could control both guns . There was a big switch in the Gunar room for local or remote operation. In my 5 years with the navy ,we only tried it once.

 In the 69 (fwd) room there was a cabinet that was called the ballistic converter. Its  input was the firing solution for the 3/70. Its output was the solution for the 3/50 gun. The 69 room had a parallax correction box to account for the positions of the guns from the director

Both systems used coarse and fine synchros throughout except the signal to the 3/70. As the 3/70 was a British designed gun , its input came from magslips. In the director gearbox,  were the magslip transmitters for training and elevation. The SPG 48 would auto track the target. All the operator had to do was sit back and watch the screens and see the projectiles  fly around the target. If I remember correctly,  the three screens were about 8" in diameter One screen was for range,  one for bearing  and one for elevation.

All systems employed vacuum tubes except for the parallax correction unit. It was solid state  The SPG 48  occupied five  cabinets: low voltage  power supply, high voltage power supply,   control unit with screens/controls, and the transceiver for the antenna. The range screen had two traces. The top one had a "bucket" that was a fine range, Once you got the target  in the range bucket, you would step on the floor switch to engage the auto track. The lower track had a step at the coarse range setting..

To add to this, the Mk69 had the circuitry to control both fore and aft guns firing in battery.  In aiming two guns separated by a good portion of the length of the ship, the control system had to factor in the parallax error.  Ie, the fact that the two guns would have to be aimed differently to hit the same place in the sky or on the ocean.

In the Restigouche class, the forward fire control  Mk 69 system was not in the same location as it was on the St Laurent class. The St Laurent  class had their forward Gunar on the main deck, starboard side, just aft  of the gun.  The 257 class  had the Mk 69 room one deck below on the port side.  We still had the old Gunar room but the amplidynes for the 69 director were in there along with a 400 cycle motor alternator (M/A) for the forward gunnery system. This was a backup for the ship's main 120 volt, 3 phase , 400 cycle supply.  We had a second one for the aft Gunar. It was located in the gun support  of the 3"/50 gun. In the gun support was also the 3"/50 power control ,the control amplifier , two amplidynes , the 400 cycle M/A and the AN/SPG-48 transceiver.  The transceiver for the forward SPG-48 was in a little space under the  Mk 69 director. HMCS Chaudiere had two large 120 volt,  3 phase, 400 cycle M/A's.

The 3"/50 ready-use magazine was located across from the canteen but it never  had any shells stored in it.  Instead, the crew used it for beer storage. If the ship was going to be away for a long period, it was filled  to capacity with  beer. Crew members could buy 2 cans of beer per day".

None of the  Restigouche clkass was  converted to DDH..
The electronics fit was referenced from Wikipedia. (incomplete)

ON BUILD

1 × SPS-12 air search radar
1 × SPS-10B surface search radar
1 × Sperry Mk.2 navigation radar
1 × SQS-10 o hull mounted active searchsonar
1 × SQS-501 (Type 162) high frequency bottom profiling sonar
1 × SQS-502 (Type 170) high frequency Limbo mortar control sonar

1 × DAU HF/DF (high frequency direction finder)
Radios: ?

AFTER IRE CONVERSION

AN/ULQ-6 jammer/deception repeater and  is used in combination with the AN/WLR-1 receiver.
A/N WLR-1C radar analyzer with AS-899 antenna inside a dome.
AN/UPD-501 radar detector
A/N SRD-501 HF/DF
Radios: ?

1 × UQC-1B "Gertrude" underwater telephone
1 × GUNAR (Mk.69 FCS  SPG-48 directors
1 x Forward FCS Mk 69

DELEX

CANEWS (Cdn. Electronic Warfare System. added)
AN/ULQ-6 jammer

Jim Brewer also describes the Gun Direction Room (GDR). "On the Restigouche class, the GDR was a small space just aft of the OPs room that housed a radar display known as a  Target Designation Indicator (TDI).  This display  could be fed from any the three main radars.  It had four joy sticks , one at each corner of the front panel. Up to for targets could be designated via one of the four joysticks.

The remainder of the controls were mounted on one side of the unit. The CRT was waist high so the operator had to stand in order to operate it. The TDI was used to "hook" a target and send the info to the Gunar room(s).

The joysticks controlled four, half circles, each  with a dot in the middle. They could be moved anywhere on the screen. This device was meant to handle four guns. The gun bearing and the fire control range positioned the other half of the circle on the screen.  The control for this thing was in the Main Switch board. There were two cabinet there,  both about the size of a fridge. One housed the electronics to create the circle and the other had the synchros to position the circles.

One joystick was for the 3in /70 gun and an other one for the 3 in/50. A third stick controlled he visual sight control panel.  When the gunnery officer picked a target , he would press a button on the top of the stick. That would send the range and bearing data to the AN/SPG 48 radar. The operator would then press a button  and the gun would position it self on the assigned target. The weapons officer would know that by the fact that the gun "half circle" joined up with his assigned "half" to make a complete circle.

This system would also work with a height radar that the ships did not have. There were two small dials on the bulkhead that were always sent a 10 deg elevation signal. This info was sent along with bearing and range. There where a lot of vacuum tubes in the "circles" cabinet.

Four visual sights were located just behind the bridge. These  could send bearing and elevation to the guns. The maintenance of these this equipment was not up to par.  The control box in the base  of these sights  and the selector switch box always flooded with water and shorted out. The control box was so bad that my PO drilled holes in the bottom to let the water run out".

SYNCHROS and MAGSLIPS

Synchro's and magslips are devices to transmit and  receive rotary information . In the late 1950s, Canadian ships  used synchros because most foreign equipment was US made.  All Canadian made equipment  like the plot table and VK5 radar repeater used synchros. There was a big difference in the  size of the units depending on the frequency of the power. A  60 cycle synchro was about 3 1/2" diameter and 4" long whereas a 400 cycle was about  1 1/4 " diameter  and 2" long. The Sperry Mk 2 radar used a 60 cycle synchro' to transmit the antenna position to the display. In the display, there  was a  differential synchro that made the display show north at the top of the screen regardless of the ship's heading. There was also a micro switch in the antenna that caused the heading to flash on the screen.

In contrast, the Royal Navy used Magslips instead of Synchros to accomplish the task of receiving or transmitting rotary information between pieces of equipment. The  sight for the British built 293 is one example of gear which used magslips.  Also fitted In HMCS Chaudiere  was a magslip to synchro converter.

A simple two-synchro system. (Image via Wikipedia)

Credits and References:

1) Cadillac of Destroyers by Ron Barrie and Ken Macpherson. Vanwell Publishing  1996
2) https://en.wikipedia.org/wiki/HMCS_Restigouche_(DDE_257)
3) https://www.hazegray.org/navhist/canada/postwar/restigou/
4) Jim Brewer
 
 

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Feb 26//24