Major Shaitan Singh
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To finish up the tour of IROQUOIS, I will walk through some of her exterior features and equipment. When the IROQUOIS class received the TRUMP refit in the 1990s, they were optimized for Air Warfare, but retained the Undersea Warfare capability originally fitted, and had limited Surface Warfare capability. Some of the photos here go back to the 1990s, and may have been taken on ATHABASKAN. My understanding of these systems is very basic, so my descriptions will not be very detailed. Which is probably just as well.
Undersea Warfare:
Designed as anti-submarine destroyers, IROQUOIS and her sisters were fitted with the latest in Canadian sonar equipment, originally the Computing Devices Canada (CDC) SQS-505 hull-mounted and variable depth sonars. These were later upgraded to the SQS-510 model. A number of years ago, I wrote an outline on RCN sonar systems here.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-4xzSVjJ%2F0%2FL%2Fi-4xzSVjJ-L.jpg&hash=b2876a6baf97a95bbc40a5b8537e5ae0)
SQS-510 Hull Outfit C3 sonar dome, removed for maintenance. The fairing itself is seen at bottom left, and is facing backwards.
Unlike the huge low-frequency bow-mounted sonar domes favoured by the US Navy and others, the RCN currently uses medium-frequency sonars in a smaller faired dome, situated just forward of the bridge. In previous classes, the sonar dome was originally designed to be retracted into the hull to reduce the ship's draft when entering port, but they were later fixed in the down position. I believe IROQUOIS was designed with the dome in a fixed position. This means that special care must be taken when dry docking these ships, to the extent that the graving dock at the Halifax Shipyard has wells cut into the bottom to accommodate the sonar dome and the propellers of these ships.
IROQUOIS also carried a second SQS-505/510 in a Variable Depth Sonar (VDS) system fitted at the stern.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-pTLW4w3%2F0%2FL%2Fi-pTLW4w3-L.jpg&hash=d6307000f605377946c4899243f68eda)
SQS-510 towfish and launching gear. Note the faired cable that would lower the towfish to depth.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-3tRQhWF%2F0%2FL%2Fi-3tRQhWF-L.jpg&hash=e83eec4b0b18ef735665e2fbb24b9f0e)
The VDS launching gear was installed in a cut-out in the transom. The operator worked behind the windows on the port side of the well, and the two ports on the starboard side are for the Nixie torpedo decoy.
The launching derrick would lift the towfish off its cradle, andpivot out over the sternto lower the towfish into the water. The towfish would be lowered to an appropriate depth via a faired cable, and would provide better detection abilities than the hull-mounted sonar as it would be not be affected by hull noise, and could be lowered below thermal layers that might mask the presence of a submarine.
![](/proxy.php?image=http%3A%2F%2Fwww.hazegray.org%2Fnavhist%2Fcanada%2Fsystems%2Fsonar%2Fsqs505-1.jpg&hash=e914665eca373fcf3a55d3fbb65c4963)
Towfish being launched. Image courtesy of Corvus Publishing Group.
VDS was a Canadian Development in the 1950s, and was adopted by several other navies before being supplanted by towed array sonar systems such as the SQR-19 / CANTASS towed array sonar fitted to the HALIFAX class. The VDS was removed from the IROQUOIS class sometime in the first decade after 2000.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-wqj4tbw%2F0%2FL%2Fi-wqj4tbw-L.jpg&hash=e268db6289134629cba367b05b553d66)
VDS towfish cradle after removal of the VDS.
Once a submarine had been detected by sonar, Mk.46 lightweight torpedoes could be deployed against it from either the ship itself or a Sea King helicopter.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-mmjQWvz%2F0%2FL%2Fi-mmjQWvz-L.jpg&hash=5b59a22e58661febb2d0dd211e8d0834)
Starboard Mk.32 triple torpedo launcher.
Unlike the fixed double Mk.32 launchers that fire at 45 degrees out the forward corners of the helicopter hangar on HALIFAX class frigates, the triple Mk.32 launcher on the destroyers was trainable and had to be directed out over the side. It is shown here in the stored position. Compressed air would be used to force the torpedo out of the tube and into the water, from where it would deploy its own motor and hunt for a target.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-Dr2cjjV%2F0%2FL%2Fi-Dr2cjjV-L.jpg&hash=1012e1b145020acb04b2b9f2543766e5)
Air droppable Mk.46 lightweight torpedo. A parachute is fitted in the cowling over the propeller nozzle.
The Mk.46 torpedo could also be carried by a Sea King helicopter, and air dropped with the help of a parachute that would detach when the torpedo hit the surface. These lightweight torpedoes are much smaller than the heavyweight ones carried by submarines.
Air Warfare:
Originally fitted for point-defence against aerial threats, the IROQUOIS class was refitted under TRUMP with area air defence systems that could extend an umbrella of protection to other ships operating in a task group, or to defend a convoy. First, all the radars were upgraded as part of that refit. (I have also written a summary ofradarsandfire controlsystem used by the RCN over the years).
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-QGwdp72%2F0%2FL%2Fi-QGwdp72-L.jpg&hash=b317020b2b57a92d184fcf96b4985174)
The main mast is bristling with sensors and other antennas.
Antennas for all of the primary air warfare sensors can be seen in the photo above. Looking from bottom to top, there is the port WM-25 Separate Target Illumination Radar (STIR), the LW-08 (AN/SPQ-502) long range air search radar, two navigation radars, and then the DA-08 (AN/SPQ 501) air/surface search radar antenna on the top of the main lattice mast.
Undersea Warfare:
Designed as anti-submarine destroyers, IROQUOIS and her sisters were fitted with the latest in Canadian sonar equipment, originally the Computing Devices Canada (CDC) SQS-505 hull-mounted and variable depth sonars. These were later upgraded to the SQS-510 model. A number of years ago, I wrote an outline on RCN sonar systems here.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-4xzSVjJ%2F0%2FL%2Fi-4xzSVjJ-L.jpg&hash=b2876a6baf97a95bbc40a5b8537e5ae0)
SQS-510 Hull Outfit C3 sonar dome, removed for maintenance. The fairing itself is seen at bottom left, and is facing backwards.
Unlike the huge low-frequency bow-mounted sonar domes favoured by the US Navy and others, the RCN currently uses medium-frequency sonars in a smaller faired dome, situated just forward of the bridge. In previous classes, the sonar dome was originally designed to be retracted into the hull to reduce the ship's draft when entering port, but they were later fixed in the down position. I believe IROQUOIS was designed with the dome in a fixed position. This means that special care must be taken when dry docking these ships, to the extent that the graving dock at the Halifax Shipyard has wells cut into the bottom to accommodate the sonar dome and the propellers of these ships.
IROQUOIS also carried a second SQS-505/510 in a Variable Depth Sonar (VDS) system fitted at the stern.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-pTLW4w3%2F0%2FL%2Fi-pTLW4w3-L.jpg&hash=d6307000f605377946c4899243f68eda)
SQS-510 towfish and launching gear. Note the faired cable that would lower the towfish to depth.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-3tRQhWF%2F0%2FL%2Fi-3tRQhWF-L.jpg&hash=e83eec4b0b18ef735665e2fbb24b9f0e)
The VDS launching gear was installed in a cut-out in the transom. The operator worked behind the windows on the port side of the well, and the two ports on the starboard side are for the Nixie torpedo decoy.
The launching derrick would lift the towfish off its cradle, andpivot out over the sternto lower the towfish into the water. The towfish would be lowered to an appropriate depth via a faired cable, and would provide better detection abilities than the hull-mounted sonar as it would be not be affected by hull noise, and could be lowered below thermal layers that might mask the presence of a submarine.
![](/proxy.php?image=http%3A%2F%2Fwww.hazegray.org%2Fnavhist%2Fcanada%2Fsystems%2Fsonar%2Fsqs505-1.jpg&hash=e914665eca373fcf3a55d3fbb65c4963)
Towfish being launched. Image courtesy of Corvus Publishing Group.
VDS was a Canadian Development in the 1950s, and was adopted by several other navies before being supplanted by towed array sonar systems such as the SQR-19 / CANTASS towed array sonar fitted to the HALIFAX class. The VDS was removed from the IROQUOIS class sometime in the first decade after 2000.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-wqj4tbw%2F0%2FL%2Fi-wqj4tbw-L.jpg&hash=e268db6289134629cba367b05b553d66)
VDS towfish cradle after removal of the VDS.
Once a submarine had been detected by sonar, Mk.46 lightweight torpedoes could be deployed against it from either the ship itself or a Sea King helicopter.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-mmjQWvz%2F0%2FL%2Fi-mmjQWvz-L.jpg&hash=5b59a22e58661febb2d0dd211e8d0834)
Starboard Mk.32 triple torpedo launcher.
Unlike the fixed double Mk.32 launchers that fire at 45 degrees out the forward corners of the helicopter hangar on HALIFAX class frigates, the triple Mk.32 launcher on the destroyers was trainable and had to be directed out over the side. It is shown here in the stored position. Compressed air would be used to force the torpedo out of the tube and into the water, from where it would deploy its own motor and hunt for a target.
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-Dr2cjjV%2F0%2FL%2Fi-Dr2cjjV-L.jpg&hash=1012e1b145020acb04b2b9f2543766e5)
Air droppable Mk.46 lightweight torpedo. A parachute is fitted in the cowling over the propeller nozzle.
The Mk.46 torpedo could also be carried by a Sea King helicopter, and air dropped with the help of a parachute that would detach when the torpedo hit the surface. These lightweight torpedoes are much smaller than the heavyweight ones carried by submarines.
Air Warfare:
Originally fitted for point-defence against aerial threats, the IROQUOIS class was refitted under TRUMP with area air defence systems that could extend an umbrella of protection to other ships operating in a task group, or to defend a convoy. First, all the radars were upgraded as part of that refit. (I have also written a summary ofradarsandfire controlsystem used by the RCN over the years).
![](/proxy.php?image=http%3A%2F%2Fsmcclearn.smugmug.com%2Fphotos%2Fi-QGwdp72%2F0%2FL%2Fi-QGwdp72-L.jpg&hash=b317020b2b57a92d184fcf96b4985174)
The main mast is bristling with sensors and other antennas.
Antennas for all of the primary air warfare sensors can be seen in the photo above. Looking from bottom to top, there is the port WM-25 Separate Target Illumination Radar (STIR), the LW-08 (AN/SPQ-502) long range air search radar, two navigation radars, and then the DA-08 (AN/SPQ 501) air/surface search radar antenna on the top of the main lattice mast.