On April 7th, for the second time since 2013, a Russian Oscar class nuclear submarine caught fire while undergoing refurbishment. This time it was in a shipyard on the north (arctic) coast. The one in late 2013 was in a Pacific coast shipyard. In both cases the fire was put out quickly and there were no weapons on board. The Russians are pretty strict about r reactors being shut down and weapons removed before the shipyard work begins. Thus there was no radiation leak or damage to the sub’s reactor during either fire. In both cases the fire was started when tools or welding ignited some rubber insulation and spread to other flammable material. The 2013 fire took five hours to put out and killed 14 people. The 2015 fire did not kill anyone.
After the 2013 fire the government called for improved supervision of work on submarines to prevent incidents like this. That was the fourth submarine fire since 2006 and the latest one makes it five. Fires don’t always happen in shipyards but that is where a sub is most vulnerable to such accidents. Russia has always had problems getting competent management in its naval shipyards and that became worse after the Soviet Union collapsed in 1991, and the more capable shipyard managers could find better paying jobs in the civilian sector. This was unfortunate, because these yards were getting a lot of tricky refurb and upgrade jobs for aging Cold War era nukes.
In 2001 Russia decided to rebuild its' eight Type 949A SSGNs (nuclear powered cruise missile submarine) so they can carry a variety of missile types. Known as the Oscar II in the West, each of these subs was designed to carry 24 large anti-ship missiles. But by rebuilding the missile launchers (which are outside the pressure hull) to carry more, but smaller missiles, each Oscar II can carry up to 72 missiles. This makes it easier to overcome the anti-missile defenses of enemy surface ships. What is lost in range and warhead size will be made up with better target detection and countermeasures technology.
The Oscar II class 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. Seven Oscar IIs remain, as the Kursk was lost in 2000 to a well-publicized accident (a torpedo exploded onboard while the sub was underwater). The Oscar's 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, meaning they are very large ships. They have eight torpedo tubes (four 650mm/25.6 inch, four 533mm/21 inch) and twenty-four SS-N-19/P-700/Shipwreck/Granit 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 Oscar's are expensive to operate and because the United States and Russia are no longer at each other's throats, especially on the high seas, the Oscars were scheduled for retirement over the next decade, as their nuclear reactors came due for refueling. The decision to refurbish the Oscar IIs indicates that the navy believes it won't get money for replacement boats. The government promises new subs, but many admirals don’t want to take a chance (by retiring the Oscars) and found like-minded people in the government who agreed to fund the refurb program.
The key upgrade involves taking advantage of the fact that the P-700 missile is an older, and bulkier, design. New launching tubes would allow it to fire more of the smaller Yakhont (also known as Oniks, P-800, or 3M55). This is an 8.9 meter (27.6 foot) long, 3 ton missile, with a 300 kg (660 pound) warhead. Early ship launched versions had a range of 120 kilometers, but the more recent models have a range similar to the Harpoon. The big advantage of the Yakhont is its high speed (about 2,500 kilometers an hour). This makes it more difficult to defend against.
In comparison, the U.S. widely uses the 546 kg (1,200 pound) Harpoon anti-ship missile. Harpoon is 4.6 meters (15 feet) long, has a 222 kg (487 pound) warhead, and a range of 220 kilometers. It approaches the target low, at about 860 kilometers an hour. GPS gets the missile to the general vicinity of the target, then radar takes over to identify and hit the target. The Harpoon has successful combat experience going back two decades. Most corvettes and many frigates are small enough to be destroyed by one Harpoon. Yakhont does more damage because of the high speed and greater weight. Russia wants to follow the Harpoon model, not the old one that was obsessed with sinking American carriers.