Hydrodynamic design implications for a submarine operating near the surface

Conventional submarines (SSKs) are regularly required to operate near the surface to run diesel engines to recharge batteries, for surveillance, and for deployment and recovery of special forces. When operating close to the surface, submarines generate waves which cause added resistance, resulting in a reduction in speed and/or an increase in power required. This can have an adverse effect on the submarine’s range and endurance, which may need to be taken into account when assessing the operability of a proposed SSK design.

Studies are being conducted by the Australian Defence, Science & Technology Organisation (DSTO) in conjunction with the Australian Maritime College (AMC) to identify and quantify the effects of submarine depth and speed on the increase in straight line resistance caused by operating close to the surface. In the study to date, two model configurations: a bare hull with and without the sail; were tested over a range of depths and speeds. The results show increased resistance for both configurations at shallow depths when compared to the deep water value.