There is an aspect of submarine operations where the Russian and U.S. Navies take fundamentally different stances. The latest Russian submarine to enter service, B-274 Petropavlovsk-Kamchatsky, illustrates this. She is unlike anything in U.S. Navy service because she is conventionally powered, meaning that she does not have a nuclear reactor. For comparison the last time the U.S. Navy commissioned a non-nuclear submarine was in the 1950s.
The latest Russian Navy submarine to be commissioned, B-274 Petropavlovsk-Kamchatsky, in St. … [+]
Russian Ministry of Defense
The new Russian submarine is an Improved Kilo Class boat. She is one of 13 project 636.3 variants expected to enter service. Unlike nuclear submarines she uses heavy-duty lead-acid batteries to power the propeller. These are occasionally recharged using diesel generators, an arrangement known as diesel-electric.
The last U.S. Navy conventionally powered submarines were the Barbel Class built between 1956-58. Thereafter only nuclear powered submarines have been built. One reason is because the U.S. Navy requires its submarines to travel long distances from their bases to where they will be needed. Nuclear submarines have virtually unlimited range so the main limitation on its endurance is the people. Patrols of over 1 month are common, and sometimes much longer. This compares to weeks for most conventional submarines.
Nuclear submarines are also faster and have more surplus energy which can be used to power massive sonar arrays. In open water this makes them much more deadly because they can hear the enemy further away and then move faster to get into position, or get out of trouble. The U.S. is not alone in abandoning conventional submarines. The Royal Navy and French Navy have too.
The first and most obvious strengths are that they are smaller and thus cheaper to build. And cheaper to crew. And they can turn off almost all systems and even sit silently on the sea floor, making them extremely difficult to detect.
Additionally, geography is such that Russia expects many of its submarines to be patrolling relatively close to their home base. This is particularly true of the Baltic and Black Sea fleets. Conventional submarines are deployed to all fleets, even in the vast Pacific where B-274 will be heading.
Unlike many other countries however, Russia has not yet adopted modern Air Independent Power (AIP). This means that the Kilo Class, and more modern Lada Class, have to come near the surface to run their diesel engines more often. AIP provides a submarine with an alternative way to drive the propeller without coming to the surface. This extends underwater range and increases stealth. There have been reports that the Lada Class will get AIP, but it has yet to materialize.
So the Russian Navy still values the more limited conventionally powered submarines to complement their nuclear powered boats. The quietness of these boats may give them advantages in some scenarios, particularly in shallower waters.