Forget About Chinese or Russian Submarines: The Navy Fears This Swedish Stealth Sub the Most

While AIP vessels may not be able to do everything a nuclear submarine can, having a larger fleet of submarines would be very useful in hunting opposing ships and submarines for control of the seas. Nor would it be impossible to deploy larger AIP powered submarines; China has already deployed one, and France is marketing a cheaper AIP-powered version of the Barracuda-class nuclear attack submarine.
Nuclear-powered submarines have traditionally held a decisive edge in endurance, stealth and speed over cheaper diesel submarines. However, new Air Independent Propulsion (AIP) technology has significantly narrowed the performance gap on a new generation of submarines that cost a fraction of the price of a nuclear-powered boat.

A conventional submarine’s diesel engine generates electricity which can be used to drive the propeller and power its systems. The problem is that such a combustion engine is inherently quite noisy and runs on air—a commodity in limited supply on an underwater vehicle. Thus, diesel-powered submarines must surface frequently to recharge their batteries.

The first nuclear-powered submarines were brought into service in the 1950s. Nuclear reactors are quieter, don’t consume air, and produce greater power output, allowing nuclear submarines to remain submerged for months instead of days while traveling at higher speeds under water.

Lees verder op nationalinterest.org