January 26, 2023: Russia’s mysterious special purpose 14,000/24,000 ton (on the surface/submerged) nuclear submarine Belgorod (K-329) has shown up again. Commercial satellite photos showed the Belgorod on the surface off the northeastern Russian coast, where several ports used by the Northern Fleet are located. Russia reported in early January that Belgorod was testing mockups of its primary weapon, the Poseidon torpedo, to make sure they could be carried and launched by Belgorod. These tests also confirmed that the nuclear propulsion system worked as expected. Belgorod is a larger and heavier Oscar class sub but it still uses the same power plant as the other Oscars. The Poseidon torpedo is too large to be carried inside Belgorod and launched from a torpedo tube, and are instead affixed to the underside of the sub and released by the sub commander. The dummy Poseidon is the same size and weight of the real one. The size and weight of the Poseidon attached to the bottom of the Belgorod changes the performance characteristics of the Belgorod and tests were done to note and fix any problems. The actual Poseidon torpedoes, which are described as a doomsday weapon, are being built and not expected to be ready for another year or two.

Belgorod was launched in 2019 and entered service in mid-2022. After that, nothing (that could be detected). Between 2019 and 2022 Belgorod had special equipment installed and tested before this modified Oscar class SSGN (nuclear-powered cruise missile submarine) was ready for service. Belgorod won’t work for the navy like other subs, but for the GUGI (Main Department of Deep-Water Researches) which works for the intelligence services and is attached to the Navy for ship and crew support.

Belgorod has come a long way since construction began in 1982. At one point the sub was canceled while still under construction. In 2006 Russia announced it would not finish construction of the Belgorod, the last of nine Type 949A SSGNs. Known in the West as the Oscar II class, these boats began entering service just as the Cold War ended. Three were in commission when the Soviet Union disintegrated in 1991. Construction continued on six more, and by 1997, eight were in service. But, at that point the navy had run out of the money, with the Belgorod not quite complete. Another $100 million was needed to complete Belgorod and the government (although not the navy) felt it wasn't worth it. Seven Oscar IIs remain in service, as the Kursk was lost in 2000, to a well-publicized accident. Work then resumed on Belgorod. That did not last long because the money was not there and not likely to be in the immediate future. Then in 2012 it was announced that the Belgorod, which had not been scrapped but put in “storage”, was once more scheduled for completion. This time there would be some major revisions that turned Belgorod into something more than an SSGN.

The original Oscars were designed as "carrier destroyers" with long-range cruise missiles that could, in theory, take out an American aircraft carrier. The Oscar II class boats have a surface displacement of 14,000 tons. They have eight torpedo tubes (four 650mm, four 533mm), and 24 SS-N-19/P-700 Shipwreck missiles. These anti-ship missiles have a range of 550 kilometers, a speed of 1600 kilometers an hour, and a 750 kg (1,650-pound) high-explosive warhead (or a nuclear warhead of 350 or 500 kilotons as an option). The Oscar's crew of 107 contains 48 officers. That's because of the high degree of automation, and the need to offer officers’ pay and accommodations to attract the technical talent required to keep these boats going.

The new Belgorod was 11 meters longer (at 184 meters) and several tons heavier than the other Oscars. It no longer carried the 24 cruise missiles but instead was equipped to handle a number of new systems. These included four to eight Poseidon AUVs (autonomous underwater vehicles) that are armed with very powerful nuclear warheads designed to release more radiation than normal. Poseidon’s are also nuclear-powered and purportedly programmed to travel autonomously to enemy coastal cities, detonate underwater and somehow create large waves that cause enormous damage and spread radioactivity along the nearby coasts. The Poseidon can travel thousands of kilometers underwater on its own, at very high speed for a torpedo (hence its own nuclear reactor) before detonating the two-megaton warhead while on the seabed of the continental shelf. Such doomsday weapons would allegedly be used only if Russia lost a nuclear war in order to punish its opponents even more. In that sense Poseidon is a psychological terror weapon, something the Russians have long been fond of. It’s an expensive obsession because creating the Belgorod and Poseidon torpedoes and their Cobalt radiation warheads cost billions of dollars for a weapon that may never be used and if it does get used, may not work as expected. After all, how do you test the Cobalt super bomb to confirm that it works?

With that in mind, Belgorod also can transport a new (since 2003), smaller (65 meters long) and nuclear-powered Losharik mini-sub underneath it. This mini-sub can perform various operations using remotely controlled arms. It 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 tampering 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.

Belgorod can also transport a Shelf nuclear power plant that can be placed on the ocean floor to power the Harmony system of underwater sensors or any other new tech that needs to be powered for a long time. Power supplies similar to Shelf have been used in space satellites that require a lot of power (like those equipped with radar).

Belgorod is also equipped to carry combat divers (similar to U.S. SEALS) and Harpsichord AUVs that are the size of standard torpedoes but contain side-scan sonar and other sensors that can operate while up to 2,000 meters underwater. Belgorod is also designed to tow objects behind it. These can be a towed array sonar or other items.

Russia already has some specialized subs equipped for special operations. These are conversions of existing subs while Belgorod was custom designed and built for the special operations tasks. In late 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 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 Losharik minisub beneath it.

The United States has also converted four SSBNs, but not for intelligence work. In early 2011 the USS Florida, an 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 Ohio. 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 carries 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 underwater (ignoring weather, or observation) at a speed of over 1,200 kilometers a day to a far off hotspot, 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 tons, has a range of 1,600 kilometers and travels 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.

The Russian special operations boats are certainly special with their nuclear-powered mini subs and AUV nuclear-armed mini-subs as well as the sensor equipped smaller mini-subs.