3. Air-Independent Propulsion (AIP) Systems
Modern AIP systems mark a major progress in non-nuclear submarine propulsion. By allowing conventional submarines to stay down for weeks instead of days, these devices greatly increase their operational capacity. The most recent AIP technologies create just water as a waste by running fuel cells combining hydrogen and oxygen to generate energy. This neat and effective mechanism increases underwater endurance and offers almost silence. For smaller navies unable to operate nuclear submarines, advanced fuel cell systems now have better hydrogen storage options and enhanced oxygen generating systems, which makes them more sensible and affordable.