Submarines: Too Much To Handle

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November 27, 2019: Despite the priority the U.S. Navy has attached to its nuclear sub program, and the recent success in producing new Virginia class subs on time and under budget, that is changing. The malaise that has wrecked so many other American warship building programs has spread to the nuclear sub construction effort. The most urgent problem is the management of the two commercial shipyards that build nuclear subs. There have been increasing problems with quality control, which means faulty work has to be done over and that means more delays. The navy, to its credit, has been paying attention and has caught the flawed work. This is due to the still vivid memory of two SSNs (nuclear attack sub) that were lost in the 1960s because of construction flaws. Ever since then the navy has paid particular attention to quality control and has caught bad habits reappearing several times and put an end to it. This time around there is another problem; many of the experienced shipyard workers are retiring and, because of a nationwide shortage of skilled workers, it is difficult to find and attract qualified workers to replace the retired ones and maintain the rapid pace of constructing new subs. This is further complicated by the need to build new Columbia class SSBNs (nuclear powered ballistic missile subs) to replace the elderly Ohio class boats. The first of the new Columbias must be ready for service by 2031, and keep coming on a regular basis, to replace the retiring Ohios.

What the Navy is spending a lot of money on is new subs. The Navy is putting its 17th Virginia class SSN into service in early 2020. The South Dakota (SSN 790) took three years to build and is the seventh of eight Block 3 Virginias. Ten years ago the navy got its fifth Virginia eight months ahead of schedule and under budget. At that point, the Virginias were taking 5-6 years to build and arriving at the rate of one a year. Over the last five years, the speed of construction has increased as well as the rate of delivery (now one or two a year) in order to replace the aging Los Angeles class boats. In one recent 25 month period, five Virginias were put into service. Now new Virginias are being built at the rate of two a year. Finally, the next batch of Virginias are 30 percent larger than the previous ones because they will have 40 launch tubes for cruise missiles. This is about three times as many cruise missile tubes as the previous Virginias. That means even more skilled workers are needed.

The Columbias are similar to the Ohios they are replacing but are designed to be less expensive to operate and offer more comfortable accommodations for the crews. This will be done by incorporating much of the technology found in the new Virginia class SSNs. The cost of developing and building the twelve Columbias will be about $128 billion. About half of that is for development and the rest (about $6 billion each) for building the new SSBN. Construction is supposed to start in the early 2020s.

There are some major differences. While the Ohios carried 24 Trident SLBMs (Submarine Launched Ballistic Missiles), the new Columbias will each carry 16 Tridents with room available to accommodate a larger missile in the future. Both SSBNS have accommodations for 155 personnel but while all of those on the Ohios were crew, the operating crew for the Columbias will be smaller with the now empty bunks available for specialists (technical, special operations or whatever).

The SSBN admirals point out that cheap isn't always cheap in the end. Thus one of the major new technologies for Colombia is a nuclear reactor that will last the full life (40 years) of the boat. In the past, nuclear-powered warships had to have their depleted nuclear fuel replaced after 20-30 years. That's expensive and time consuming. For example, the Nimitz class carrier Carl Vinson (CVN 70) entered service in 1982 but, 25 years later, had to undergo a three year refurbishment that included the refueling plus a long list of upgrades. All this cost $3.1 billion. The nuclear refueling accounted for 16 percent of that.

Submarines, because they are smaller, have required refueling every 5-20 years. The latest SSNs (Seawolf and Virginia) use a new reactor design that eliminates the need for the elaborate (taking apart the reactors, and part of the ship) refueling process. The next American carrier, CVN 21, will also use this new technology. But SSNs have a life of only 30 years, so a new reactor design will be required for the SSBNs, which serve 40 years. It costs a billion dollars to refuel a nuclear sub.

The Columbia will be quieter, to keep up with advances in submarine detection technology. That costs a lot, although much can be borrowed from the Virginias. Go cheap on this, and the SSBNs are less valuable as a deterrent as they are easier to find and destroy just when they are needed. Finally, there is the need to incorporate labor saving gear in the new SSBNs, so the crew size can be sharply (up to 50 percent) cut. It's getting harder and harder to recruit sailors for SSBN duty, and the only other way to solve that problem is with bonuses, on top of the $100,000 in annual pay and benefits, and several times that just to train SSBN sailors. Whichever way this goes (half a dozen cheap boats, or a dozen state-of-the art ones), there will be another class of American SSBNs.

Then there are the problems with larger Virginias. Each block of Virginians represents improvements, some of them substantial. There are (or will be) four Block 1s, eight Block 2s, eight Block 3s, ten Block 4s and ten Block 5s. The Navy now plans to build 66 Virginias with ten currently under construction and 17 in service. Blocks 1-4 of Virginia are all armed the same way but Block 5 (arriving in the early 2020s) will have additional space to store and launch missiles and will carry 65 missiles and torpedoes (75 percent more than Block 1-4 boats). This will be accomplished by adding an additional section (the VPM or Virginia Payload Module) that adds 25.6 meters to the length of the sub and increases displacement to 10,400 tons. Each new Block gets better electronics and sensors and it is believed that the passive sonar in the late model Virginias have much longer and accurate detection ranges. The Block 5 will also receive a large number of equipment upgrades. The main problem with the Virginias is the larger size.

The Block 1-4 Virginias cost about $2.2 billion each. They displace 7,800 tons and are 114.9 meters (377 feet) long and 10.36 meters (34 feet) wide. Top speed is over 50 kilometers an hour, max depth is more than 250 meters (over 800 feet). The Block 1-4 Virginias are armed with Tomahawk cruise missiles (in 12 vertical launching tubes) and four 53.3 cm (21 inch) torpedo tubes that can fire MK 48 torpedoes or emplace naval mines. Recently the navy resumed using the ENCAP (encapsulated in a container that is fired from a torpedo tube) Harpoon anti-ship missile. The Navy withdrew the ENCAP Harpoon in 1997 but in 2018 test fired one of them (apparently refurbished for the occasion) and found they still worked as they were supposed to. The ENCAP Harpoons were initially replaced by an anti-ship version of the Tomahawk, which was also soon withdrawn. The latest version (Block II+ER) Harpoon has a 300 kilometer range and much better terminal guidance and countermeasures. But it is still a slow (800 kilometers an hour) missile while the most modern anti-ship missiles have terminal attack speeds of more than three times that. Then again for a surprise attack Harpoon can be useful as it comes in very (“sea skimming”) low often avoiding enemy radar. So a possible situation would have an enemy ship detected by satellite or UAV with location information sent to a sub within Harpoon range (or able to move into range) which could then fire one or more ENCAP Harpoons and then go hide. ENCAP Harpoons blasting from the sea surface maks a lot of acoustic and visual noise. Another option is the ENCAP UAVs proposed for subs. These can be launched more quietly and spend several hours searching an area for any targets and sending the sub brief message bursts with the location of any targets. The anti-ship Tomahawk is also returning to use with several upgrades.

More important are the large number of electronic systems carried. These make the Virginias more difficult to detect, which enables these subs to be more effective at espionage and scouting. The electronics can also quickly detect and identify incoming torpedoes and rapidly use countermeasures. The passive (listen only) sonar system is backed by a huge library of sounds. Virginias are also designed to operate in shallow waters and carry a SEAL Delivery Vehicle (sort of a minisub for getting SEALs ashore) outside the sub. With a dozen or so SEALs on board, a Virginia will be carrying nearly 150 people. 

Virginia’s nuclear reactors are the new type that does not have to be refueled, having sufficient nuclear material to last 33 years. The reactors generate enough heat to provide 40,000 horsepower, as well as ample electricity for all the electronics. The block 2 models used less costly construction techniques, while the eight Block 3 boats have some design changes and new technology. The most dramatic improvements will come with Block 5.

The U.S. currently has three classes of SSN. Most are the 6,900 ton Los Angeles-class SSNs. Sixty-two of these submarines were built and 32 are still in service. Armed with four 53.3 cm torpedo tubes, they carry twenty-six weapons for those tubes (either the Mk 48 torpedoes or BGM-109 Tomahawk cruise missiles). The last 31 Los Angeles-class SSNs added the Mk 45 vertical-launch system (VLS), which carries another twelve Tomahawks. If built today these late model Los Angeles class boats would cost about $1.5 billion each. The first of these entered service in 1976, and the last one in 1996. These boats can last 30-35 years before they must be retired or undergo extensive (over half a billion dollars’ worth) of refurbishment and refueling. This can take 4-5 years and will keep the sub going for another 10-15 years. But there’s barely enough money to keep building Virginias and no time or cash to refurb elderly Los Angeles class boats. That was why the number of Virginias planned was increased to 66 and the tempo of construction speeded up. Thus the American SSN fleet will not shrink from 55 in 2013 to under 45 by 2030. The current building plan keeps the SSN numbers at or above fifty.

Twenty-nine 9,000 ton Seawolf-class SSNs were supposed to replace the Los Angeles boats but Seawolf proved too expensive. Only three were built. The Seawolf was designed for the Cold War, carrying fifty weapons (torpedoes, cruise missiles, or Harpoon anti-ship missiles) for its eight 660 mm (26-inch) torpedo tubes. Seawolf was fast (top speed of over 60 kilometers an hour) and much quieter than the Los Angeles boats. To replace the un-built Seawolfs the Virginia-class was designed. Think of it as a Los Angeles size hull with a lot of Seawolf technology installed. The Virginia class boats ended up costing about half as much as the Seawolfs. But that was largely possible because the Virginias used a lot of the new technology developed for Seawolf.

 


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