The DAPHNE-class submarine which served with the South African Navy stem from an original Marine Nationale (French Navy) requirement for a smaller type of submarine to supplement the larger ocean-going conventional attack submarines (SSK), then entering service. These were the large NARVAL-class of 1 630 tons, based on captured German TYPE XXI   U-boats.

HISTORY:

In 1952 the French General Staff requested a design of approximately half this tonnage to supplement the NARVAL design. Requirements included low radiated noise levels, good manoeuvrability, small crew, ease of maintenance and a deep diving capability. There were to be at least six torpedo tubes (of which two had to be stern tubes for anti-submarine torpedoes).

DESIGN:

The outer hull-form of the DAPHNE is conventional with a prominent keel for improved stability. The double-hull design is a prominent feature of early post-war French submarines, with the fuel and ballast housed outboard of the pressure hull. An operational diving depth of 300 meters was achieved with a calculated pressure hull crushing depth of 575 meters.

The internal lay-out is conventional single deck through-out, except for the two battery compartments and auxiliary machinery space. A conventional diesel-electric propulsion system was selected. This consisted of two JEUMONT SCHNEIDER electric motors each rated at 2 600 BHP. Two 1 224 BHP SEMT PIELSTICK PA8 diesel generators are used for battery charging. This combination gives a speed of 13.5 knots on the surface and 15 knots dived.