The giant supercarrier may be entering its last days in the US Navy. In defiance of Congress, America's sea service is retiring one of the last of its oil—fired flattops, the USS Kennedy  which is too old to repair and too expensive to upkeep in a fleet desperately attempting to replace its Cold War era ships. According to the recent Quadrennial Defense Review, the number of carriers will be reduced to 11, but the available airwings will number only 10.

This is coming at a time when the big ships are mostly left out of the War on Terror. Al Qaeda has no navy to speak of; the only warships seeing action are patrol ships and frigates hunting pirates in coastal waters. Billion dollar destroyers and cruisers performing the same mission appear like Goliath chasing David. The most important warships currently being built are new littoral combat ships, especially geared for such inshore operations, and at $300 million each, much more affordable.

One of most numerous type of warship,with some 300 built or building around the world, is not a new concept. It is the old style diesel/electric submarine, little—changed in basic design from its World War 2 predecessor, but updated with key technologies. The reason for the U—boat's comeback is their relatively low cost and their ability to sail under and outmaneuver the bigger surface ships. With the cost of American warships now surpassing a billion dollars each, a Third World navy can purchase a conventional sub for $100 million, or even less for a used boat.

The diesel submarine is the guerrilla fighter of sea combat, as proven in two world wars of the last century. Unable to match the might of the Royal Navy's giant aircraft carriers and battleships, Germany turned to the only weapon it had left, the U—boat. In so doing she nearly turned the tide of war in her favor, bringing British commerce to its knees.

Likewise in the Pacific War with Japan, the undersea boat outfought a more numerous and powerful foe. With the bulk of her battle fleet on the bottom of Pearl Harbor, America turned to the only weapon left which could take the war to the enemy. In so doing, the silent service sank more Japanese vessels than any other weapon during the war, including aircraft and surface ships.

Another cause for the diesel boat's current resurgence is its extreme quietness. Though America and Russia have spent billions for noise reduction for their mass fleets of nuclear boats, still the deadly silence of a battery motor underwater is unmatched. New propulsion systems are providing subs even more lethality. Russian and European vessels are now going to sea with air—independent—propulsion (AIP), which increases undersea endurance from days to even weeks. Hardly matching the unlimited range of a nuclear boat, it is still a definite improvement over the old tactic of snorkeling.

The conventional boats have become a very grave threat to the surface warship. On numerous occasions during wargames with friendly navies, diesel boats from Australia, France, and Germany have pierced the anti—submarine screen and  gotten within firing range of American carriers. Chinese subs are increasingly seen further and further from home waters. China's fleet of undersea boats include ex—Russian Kilo class which are well armed with cruise missiles, and China may also posses the new Shkval rocket, reported to reach underwater speeds of 200 knots.

The US Navy is taking the threat of the new U—boats so seriously it has borrowed  an AIP—equipped sub, the Gotland,  from Sweden. This advanced new vessel will train surface sailors in the deadly tactics which they may face against navies of rogue states such as Iran, North Korea, and even China.

Such weapons as the Shkval, supersonic missiles, AIP and even more powerful fuel cells give the new U—boats capabilities far surpassing their world war forbearers. Such add—ons may provide emerging Third World navies the means to confront even the world's greatest navies, Britain and America.

It is imperative for Western fleets to consider this reality first before straining precious ship—building funds for a few big ships. The increasing menace from comparatively low—cost submarines threatens the behemoths. Once just a threat to merchant vessels, the U—boats of the 21st century have become a direct challenge to the old order at sea.