In the summer of 1961 Europe came to a stand still during the Berlin War Crisis. NATO forces would be face to face with uncountable masses of Soviet and Warsaw Pact armour.
In response to the build up in Europe the Canadian Government brought 4 Canadian Infantry Brigade Group up to near wartime strength. New weapons were fielded to provide the Troops with both a strategic and tactical response if the Soviets attacked the west. The Honest John surface to surface missile provided Canadian Artillery with a massive punch. Nomad Helicopters and Ferrets were deployed as the Brigade's Recce screen. An Anti-Tank Company was formed using the R22eR and this sub-unit would form the basis for a Divisional Anti-Tank Battalion.
In order to equipment the Anti-Tank Company with the weapons systems it needed Canada purchased a combination of 2000 French made ENTAC and SS-11 Anti-Tank missiles. The wire guided missiles were mounted on M38A1CDN Jeeps and the M37 CDN Truck. These platforms were an interim solution while Canada waited to obtain a tracked APC with an Anti-Tank capability.
Severe limitations were discovered with the M38A1 and M37 mobility and crew protection on a European battlefield and trials began to locate a suitable armoured vehicle for the missile systems.
In order to supplement the soft skin vehicles successful testing was completed with the SS-11s mounted on a Canadian Centurion Mk.5. The mounting system was adapted from the French AMX-13/75 light tank. It consisted of a horizontal launcher platform straddling the main gun and held four individual SS-11 launcher rails. At the time the Centurion's 20 Pounder firing the M3 APDS round had a maximum effective range of 1500 metres. The SS-11 missiles had a maximum range of 3000 metres. The missile was difficult to control at ranges under 500 metres but beyond this minimum range the missile was very accurate in the hands on an experienced controller. The significant increase in engagement ranges would supplement the Brigade while defending against the Soviet armour and permit the tanks to engage with the Centurion's armour protection at distances far beyond Soviet Anti-Tank missile ranges. This would conserve main gun ammunition and reduce the effectiveness of the enemy armour by targeting their command and control vehicles with the SS-11.
The SS-11 missiles were guided by a controller in the commander's station. Four hollow charge warhead missiles mounted on the launcher rails were carried on each tank and one additional missile was carried in the turret in a special cradle attached to the top of the 20 Pounder gun basket therefore not reducing the internal stowage for the 20 Pounder rounds. Additional missiles were carried in the Echelon for re-arming. Re-arming was very quick and each 66 pound missile took about a minute to mount.
The SS-11 mounts were for the most part kept in war storage and only mounted in time of bug out alerts to pre-prepared defensive positions. A complete Centurion Troop was converted to mount the SS-11 missiles.
With the procurement of the 105 mm L7 main gun, IR sights, and further uparmouring of the Centurion the tank became much more of an offensive weapon and the static Armoured Anti-Tank role would eventually be switched to the 3 Mech Cdo M113A1s with SS-11 mounts.
Here is a line drawing from a training document of the Canadian Centurion Mk.5AT version used in West Germany.