In early October 2016 Russia finally sent its second “special operations” SSN, the Podmoskovie (BS64), to sea for trials. This sub is actually a Delta IV class SSBN (nuclear powered ballistic missile submarine) that began its career in 1986 as K64 Podmoskovie. Since 1999, K64 has been undergoing conversion to BS64, which appears to be something similar to customized U.S. SSNs that have been in service since the 1970s. The current American example of this is the USS Carter, a Seawolf class SSN converted (while under construction) to be 30 percent longer and 20 percent heavier than the other two Seawolfs. The additional space was to hold mini-subs for carrying the fifty SEALs it can carry, or to tap into underwater communications cables and perform other intelligence gathering tasks. The Carter entered service in 2005 and replaced an older Sturgeon class SSN (USS Parche) that entered service in 1991 and was retired in 2004. The Parche replaced earlier SSNs that had performed these intel missions throughout the Cold War.
The 13,500 ton Podmoskovie had its 16 ballistic missile silos replaced with facilities for launching remotely controlled mini-subs for intelligence missions. The renovations resulted in the sub becoming about five percent longer. This meant that the converted Podmoskovie was somewhat lighter (probably about 12,000 tons). The first Russian SSBN to undergo a similar conversion was the K129 Orenberg, a Delta III class SSBN whose conversion (to BS136) began in 1994 and entered service in 2008. The Delta III is about the same size and displacement as the Delta IV but the Podmoskovie conversion seems to be more extensive than the Orenberg. Both the Orenberg and Podmoskovie carry the new (since 2003) smaller (65 meters long) nuclear powered sub, the Losharik. This sub carries a crew of 25 to great depths (up to 6,000 meters) and has a top speed (for emergencies only) of 72 kilometers an hour. Losharik is believed to be for checking Russian underwater data cables for bugs (or damage in general) and more easily tamper with underwater cables and other equipment belonging to the United States and other Western states. Because Losharik can dive deeper than any other sub and is quite large for a deep diving sub it can find and retrieve useful items that end up in very deep waters (electronics from Western aircraft or ships). Losharik can also survey very deep sea bottoms for suitable sites for placing various electronic devices.
The United States has also converted four SSBNs, but not for intelligence work. On March 19th 2011 the USS Florida, American Ohio class SSGN fired its Tomahawk TLAM-E cruise missiles in combat for the first time off Libya. Most of the hundred or so Tomahawks launched that day were fired by the SSGN. This was not the first time nuclear subs have fired cruise missiles in wartime as U.S. SSNs have fired Tomahawks several times. But the Ohio class SSGNs carry 154 cruise missiles, more than ten times the number carried by some SSNs.
The four Ohio class SSGNs are SSBNs converted to cruise missile submarines (SSGN) and these first entered service in 2006. Each of these Ohio class boats now carry cruise missiles as well as many as 66 commandos (usually SEALs) and their equipment.
The idea of converting ballistic missile subs, that would have to be scrapped to fulfill disarmament agreements, has been bouncing around since the 1990s. After September 11, 2001, the idea got some traction. The navy submariners love this one, because they lost a lot of their reason for being with the end of the Cold War. The United States had built a powerful nuclear submarine force during the Cold War, but with the rapid disappearance of the Soviet navy in the 1990s, there was little reason to keep over a hundred nuclear subs in commission. These boats are expensive, costing over a billion each to build and over a million dollars a week to operate. The four Ohio class SSBN being converted each have at least twenty years of life left in them.
The idea of a sub, armed with 154 highly accurate cruise missiles, and capable of rapidly traveling under water (ignoring weather, or observation) at a speed of over 1,200 kilometers a day, to a far off hot spot, had great appeal in the post-Cold War world. The ability to carry a large force of commandos as well was also attractive. In one sub you have your choice of hammer or scalpel. More capable cruise missiles are in the works as well. Whether or not this multi-billion dollar investment will pay off remains to be seen, but it certainly worked off Libya.
The SSGNs are carrying a new version of Tomahawk, the RGM-109E Block IV Surface Ship Vertical Launched Tomahawk Land Attack Missile. Each of these weighs 1.2 ton, have a range of 1,600 kilometers and travel at 600-900 kilometers an hour. Flying at an altitude of 17-32 meters (50-100 feet) they will hit within 10 meters (32 feet) of their aim point. The Block IV Tomahawk can be reprogrammed in flight to hit another target and carry a vidcam to allow a missile to check on prospective targets.