Submarine Propulsion

Conventional (diesel-electric) submarines can provide improved stealth compared to nuclear submarines once submerged. This is because nuclear submarines are generally larger and are required to operate their nuclear reactors at all times, unlike diesel-electric submarines which are generally smaller and can run exclusively on batteries when submerged which generally requires fewer moving parts. These characteristics normally result in a smaller acoustic, thermal and magnetic signature which afford diesel-electric submarines greater stealth when submerged. However, the current underwater range and endurance is limited by the energy storage or generation for submerged operation. The application of emerging energy storage technology seeks to address this limitation and provide significant tactical and operational advantages to the conventional submarine operator. From a fire safety perspective, the potential addition of technologies such as rechargeable lithium-ion batteries, Air Indep...

A project management decision tool viz., forced decision matrix (FDM) is implemented in this paper towards identification of a suitable optimal air independent propulsion (AIP) system for submerged vehicles. FDM is utilised in order to handle the trade-off from amongst multiple propulsion technologies. FDM is based on multi-attribute utility theory used extensively in decision analysis situations involving persuasive multiple alternatives. The efficiency and effectiveness of this methodology to tackle complex solutions is elaborated in this paper with appropriate calculations. A rational decision-making procedure is evolved using the FDM in order to select the best suited AIP technology for a submerged vehicle. It is inferred that FDM is an effective and potential tool towards identification of best suitable solution in a multi-option environment.

The aspiration to improve submarine Power and Propulsion System (P&PS) performance without hazarding
the platform’s safety continues to challenge the designers of the world’s SSKs.
Technologies are reviewed in this paper which seek to improve performance in the context of the use of more
commercially-based type equipment. Recent technological developments and improvements have created the
potential to improve overall power and propulsion performance and therefore overall submarine capability.
To bring to maturity, prove and ultimately integrate such technology into a submarine design requires a firm
understanding of the actual technology in terms of the benefit it offers and its limitations, complemented by
knowledge of integrating such technology within the host submarine and its operations.
This paper will begin by defining the future challenge for SSK designers and then consider how this could be
translated into P&PS requirements. The technologies that may allow such a requirements set to be met and
the anticipated performance that may be achieved, are demonstrated in an indicative SSK 3,600 tonne design
from BMT Defence Services Limited, known as the Vidar-36.