Early Years

conventional submarines are propelled by electric motors powered by batteries which are charged by diesel generators on board. Over the years the improved efficiency of the diesel engines, better batteries and power conserving motors have attempted to limit this constraint and Ôindiscretion rateÕwhich is the total time the submarine is exposed vis-ˆ-vis the total time it is dived in a 24-hour cycle has reduced substantially. however, the challenge to overcome this inherent limitation on endurance, speed and concealment has constantly driven innovation in submarine propulsion technologies. scientists and engineers have grappled with this challenge and various technologies were attempted to design a system which would not require external air to run the diesel generator engine in what is now known as air Independent propulsion (aIp). The pioneering attempt was by a brilliant german engineer dr helmuth Walter who designed a system in the early 1930s using hydrogen peroxide as an oxidant. This system was based more upon enhancing a submarineÕs dived speed than longer dived endurance. After being fitted and tried on board a class of submarines, the programme was discontinued for various reasons, not least among them being the danger of using hydrogen peroxide on board.

submarine operations in World War II and the diminishing effectiveness of submarines due to new detection technologies led to the invention of the ÔsnorkelÕ. although this did not require the submarine to break surface for running the diesels and the batteries could still be charged while dived though close to the surface, it only addressed the problem partially as the submarine still had to expose the ÔsnortÕ mast as an air intake for the diesels. The advent of radar and sonar and the emer-