by Jerry Proc

When World War II broke out, there was no radar industry in Canada and any requirements for naval radar had to be filled by the British. This was not considered a satisfactory arrangement, therefore, the National Research Council in Ottawa started development in 1941, on the famous (or infamous) SW1C radar. The acronym meant 'Surface Warning 1st Canadian'. This system saw its service debut in RCN ships starting in 1942.

According to many who used it, the SW1C was considered a menace. A target on the starboard bow could just as well be on the port quarter. Practical experience indicated that the set had a propensity to generate false echoes and the long pulse of the set meant that it could detect nothing within a half mile of the ship. This level of performance from the system did not instill confidence to those who had to operate it. Part of the blame can be assigned to the scientists who failed to design a sailor and sea- proof set and the RCN which trained operators and not maintainers. By the time the RCN began to look seriously at the need for qualified radar personnel, the country had been stripped of them in order to support the high-tech air war in Europe. As late as 1943, the navy had to draft RCAF radar technicians for its corvettes in order to keep the radars running. Quite apart form numerous U-boat contacts which went unnoticed in the clutter of echoes displayed on the glowing CRT, the set was the active cause of many serious accidents and collisions, putting some ships aground and ramming others into other unyielding objects. It was infuriating for the Officer of the Watch to vainly search for objects reported by the SW1C only to have something large and substantial go streaming by and then discover that the operator did not detect it on his wretched set. As an example, off the coast of Labrador, on a clear sunny day, it might detect a tiny piece of floating slush at an amazingly long range, and at midnight it would fail to detect an approaching iceberg!

Due to poor liaison, the RCN never realized that the Royal Navy had already introduced a superior new generation of radar (271 type) in 1941. Ascertaining why the Canadians got off to a late start requires some speculation, since the documentary evidence is incomplete. It is significant that the decision to opt for the SW1C was made prior to large scale RCN involvement in anti-submarine warfare. As a result, SW1C was obsolete in its primary role as a submarine detector before it entered production and the RCN committed to its production for at least a year after 271 entered service. Due to this commitment, the RCN, for the rest of the war, was unable to provide the timely supply of sufficient centimetric sets for its own growing escort fleet. In spite of being given the highest priority rating, production of the SW1C was delayed due to the shortage of small motor-generators and vacuum tubes. By the last week of 1941, only fifteen corvettes and three merchantmen were fitted with the SW1C.

The SW1C antenna consisted of a rotating, rake-like, multi-element, Yagi antenna. It was also ironical that this antenna was invented by a Japanese physicist. Rotation was provided by a rather cumbersome and primitive mechanism composed of a horizontal steel shaft connected to a sprocket and chain reduction gear, which in turn, was rotated with, of all things, a Chevrolet steering wheel mounted in the RDF office! On every ship that was fitted with SW1C, this arrangement became known as 'the plumbers nightmare'. Repeated failures of the main rectifier tube continued to plague the set, but modifications were made to replace the tube with an improved model. Beam accuracy was also improved to within 5 degrees and more importantly, bearings were possible over a 360 degree arc. This was a major improvement over the Admiralty's 286 set whose accuracy and directional search was limited by its fixed antenna.

The transmission line between the set and the antenna was saturated with nitrogen gas in order to reduce signal attenuation. It proved to be a cumbersome arrangement which caused major headaches from January 1941 until the end of its service life in 1943. A recurring failure of a co-axial cable seal allowed sea water into the cable, which in turn, introduced losses and attenuated the signals to the point where it rendered the set almost useless. The stresses and strains of rotating a mast-top aerial were extreme, especially when effects of high winds, severe winter icing, and the ship's movements were taken into account. Adding to this, was the requirement to purge the co-axial cable at periodic intervals. Of course, the gas bottle that performed this task was fitted in the operator's cabin, but the valve that had to opened to vent the line was located - where else? - at the top of the mast. Climbing aloft to purge the line during a midnight blizzard was an experience that must still haunt former RCN radar operators. One rating actually stood on the wheel house roof throughout a Cape Cod blizzard rotating the broken antenna by hand with a Stillson wrench while the ship groped through an oncoming convoy. He was rewarded and revived by five successive hot buttered rums in the wardroom upon arrival.

Regardless of the problems, production of the set continued into 1942. The first major model change was the conversion of the SW1C to 214 megacycles to make it compatible with Identification, Friend or Foe (IFF) sets and additional improvements to the Yagi antenna. This re-designed set was known as the SW2C and formed the bulk of the units fitted on corvettes and minesweepers. In later productions, the SW2C set was modified for use on small ships such as Fairmiles and motor torpedo boats and was renamed the model SW3C. The major difference was a modified Yagi antenna which was lighter and slightly different in design. This variant entered service in mid-1942. Until ten centimetre radar equipment became available in large quantity in mid-1943, the SW series was the only radar available to the RCN in great quantity. Long after the Admiralty had removed the 286 from service, the SW2 was retained by the RCN for aircraft detection and a reserve set. The decision made by the RCN to continue production of the SW1C made sense at the time as it was next to impossible to procure 271 sets in great quantity.

When centimetric radar entered widespread use in the autumn of 1943, the Royal Navy Western Approaches Command tried to convince the RCN to remove the SW series set from its vessels as it was considered a maintenance nuisance. The SW2C was defended with vigour by most Canadian operational commanders and Naval Staff who not only wanted to retain them, but improve them as well. This attitude led to the design of the SW2C/P and the SW3C/P sets which had a defect-free antenna and a plan position indicator (PPI) display. This permitted the SW series to continue in service until the end of 1943. Regardless of the faults of the SW1C, RCN officers managed their battles with much less information than their British counterparts - a situation that called for exceptionally high standards of co-ordination, leadership, training and seamanship.


1) Zimmerman, David. The Great Naval Battle of Ottawa. University of Toronto Press. Toronto, Ontario. 1989.

2) Lynch, Thomas G. Fading Memories - Canadian Sailors and the Battle of the Atlantic. The Atlantic Chief and Petty Officers Association. Sentinel Printing , Yarmouth N.S. 1993.

3) Curry, Frank. War at Sea - A Canadian Seaman on the North Atlantic. Lungus Productions. Toronto, Ont. 1990.

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