The South African naval and coastal defences were in a state of constant development throughout the interwar period. South Africa, however, remained reliant on the United Kingdom (UK), and the Admiralty in particular, for its coastal and naval defence. At the outbreak of war, the Union Government was determined to re-establish a distinctly South African naval asset to control its maritime defence. The Admiralty, however, viewed these developments with concern. The idea of re-establishing the navy had an unequivocal effect on Anglo-South African naval relations and the conduct of the naval war in South African waters.
The Seaward Defence Force (SDF) officially assumed the responsibility for South Africa’s coastal and naval defences in January 1940. Without delay, it took over the former British responsibilities of minesweeping (M/S), anti-submarine (A/S) duties, Port War Signal Stations, Examination Services, and other fixed naval and harbour defences at the principal South African ports. South Africa, however, remained somewhat reliant on the Admiralty for technical and training support, and for the provision of specialised equipment needed for coastal defence. The exigencies of the naval war in the Southern Oceans naturally tested the Union’s coastal and naval defences.
This chapter has three broad objectives. Its first objective is to investigate the formation of South Africa’s coastal and naval defences during the interwar period, especially against the backdrop of economic rationalisation and Imperial defence. The second objective is to critically discuss the creation of the SDF and Anglo-South African naval relations at the outbreak of the war. Last, the chapter evaluates the development of a comprehensive South African coastal defence system during the war.