Have you heard about the two "Blonde Submarines"?

Early AIP (Air-Independent Propulsion)

Development of air-independent propulsion systems began in Russia and Germany in the 1930s. In World War II the Soviet Union and Germany developed AIP systems for their submarines. The Soviet-designed AIP system used liquid oxygen and diesel fuel to operate a closed-cycle diesel (CCD) engine that was installed on submarine M-401 for an experiment that lasted from 1940 to 1945.

In 1946 U-boat U-1407 was salvaged and commissioned into the Royal Navy as a model for High Test Peroxide (HTP) submarines. U-1407 was a prototype for two British experimental submarines, HMS Explorer and Excalibur. Built for speed, their HTP engines were steam turbine generators from the exothermal reaction of HTP with diesel oil and a catalyst.

Explorer and Excalibur known as the 'blonde' submarines because hydrogen peroxide was also a popular dying agent for blonde hair. Units of the 3rd Submarine Squadron, the subs (capable of 25 knots submerged) were intended as high-speed targets for Royal Navy practice.

Stored outside the pressure hulls, the HTP was prone to exploding unexpectedly. On at least one occasion the crew were forced to evacuate. The fuel proved to be so toublesome that the boats eventually became known as Exploder and Excruciator.

USS Nautilus (SSN-571) got "underway on nuclear power" in January 1955. Nuclear power was a much more satisfactory method of AIP, so the HTP project was abandoned, and Explorer and Excalibur were decommissioned (1960s).




Nautilus AIP submarine...

Today's fuel cell AIP submarines use a variety of fuels to generate electrical power. Have nuclear powered submarines finally been leapfrogged? In performance no, but in sheer number perhaps that time will arrive.

"... new underwater weapons will help equalize the performance disparity between AIP boats and nuclear-powered submarines and it may well happen that the U.S. Navy will want to reassess the desirability of developing an AIP submarine of its own, if only to learn how to counter this new and potentially revolutionary undersea challenge."

- Don Walsh, The AIP Alternative Air-Independent Propulsion: An Idea Whose Time Has Come?; Navy League of the United States