Our secret radar helped win the war

During World War Two (1939-1945), about 150 disastrous sinkings by enemy action took place within 1 000 miles of Cape Town. Ships conveying strategic supplies and troops travelling the then only route between East and West were continually preyed on by lurking submarines (U-boats) and raiders.

Almost 18 000 ships called at Cape Town so the losses would have been far greater if it had it not been for the 17 'hush hush' radar stations operated by the SSS - the Special Signals Services - specially erected at the request of Britain - to electronically pin-point the enemy (not to defend SA!).

Often isolated on high vantage points, they monitored all air and surface craft within about 200 km. Mainly women operated this new-fangled apparatus 24 hours a day in all weathers examining tiny 'blips' on their small TV-type 'screens'.

Radar readings were sent via the SSS Filter Room to the military Combined Operations centre at The Castle who decided whether to despatch one of the few available SAAF aircraft to investigate and possibly attack. When the enemy became wise to our radar they tended to keep well away - while the shipping travelled closer to the (rather treacherous) coast. At the stations, security guards armed with assegais defended the secrets from inquisitive local pro-Hitler elements -or a possible enemy landing party.

In one day in 1941 there were 80 ships in the Bay and as yet only one radar station countrywide. Gradually more became active. In 1942 an expected Japanese bombing of Cape Town fortunately never materialised, nor a carefully planned night surprise attack by two U-boats. During the War our aircraft managed to sink at least two U-boats, while others were damaged.

All stations operated continuously but because of the secrecy there are few records. However an operator at the Signal Hill radar station (in 1941 the country's first) specially remembers continually plotting strange 'tracks' west of the Peninsula in 1942 - but Ops were unable to investigate. Up to thirteen merchant ships were sunk in the area by U-boats which it is believed had been replenished by a 'tramp' mother ship lying up for 'repairs' off Hout Bay. This was subsequently captured.

Radar plots also helped many friendly ships from running aground in poor weather and at night, as no lighthouses were functioning and there was an enforced 'wireless silence'; especially ships in unfamiliar waters with inadequate charts. Lost friendly aircraft were assisted.

A 6 000 ton vessel in heavy fog being plotted on 9 December 1942 had to be warned off Robben Island by foghorn. Later the huge liner Dominion Monarch, laden with troops, was saved from a similar disaster.

On 25 April 1943 a 10 000 ton ship was helped by rifle fire to avoid the Hout Bay rocks. Then another of 8 000 tons, carrying ammunition, was directed away from the rocks at Sea Point. Had the ship foundered and exploded a vast residential area could have been blown to bits! Others, like the American Liberty ship Thomas T Tucker, were not so lucky.

On occasions, the odd lifeboat with survivors was helped to safety. Cape Agulhas radar operators were convinced that U-boats were being replenished at night by pro-Nazi farmers near Arniston. No aircraft were available to investigate.

Initially the revolutionary transmitter/receivers were effective 'JBs', hurriedly devised by Dr Basil Schonland and his Johannesburg team from odd components. Their wavelength was 3.3m and peak power output a mere 5 kW. Radar involves the beaming of radio pulses in a specific direction. Reflections from objects appear as 'blips' on a TV-type screen on which the exact distance is indicated.

The SSS Radar Group can be contacted at mangin@mweb.co.za

For some fascinating reminiscences, visit http://rapidttp.co.za/milhist/radar.html