SUBMARINES: Turning SSNs into SSBNs
November 5, 2004: When it comes to submarine design, history does repeat itself. The U.S. Navy plans to build its next class of ballistic missile submarines by simply taking the current (quite new) Virginia class attack (SSN) submarines, and inserting a section behind the sail, in order to accommodate the missile silos. The same thing was done in the 1950s, when the then current Skipjack class nuclear attack subs were so modified to create the George Washington class SSBN. These were the world’s first SSBNs, equipped with Polaris ICBMs.
The George Washington’s were 382 feet long, displaced 6,000 tons, and had a crew of 112. The first one entered service in 1959. Five were built between 1957 and 1961, and the last of them was decommissioned in 1985 (mainly because newer, more capable ICBMs for SSBNs had been designed that could not fit in the 16 George Washington class silos.) The 13 ton, 29 foot long Polaris missiles were actually IRBMs (intermediate range ballistic missiles), as their range was only 1,800-4,600 kilometers (depending on the version). The Skipjack’s, on which they were based, were 3,100 tons displacement and 252 feet long, with a crew of 99. The Skipjack was the first modern attack sub, having nuclear power and a tear drop shape hull. The first one was ordered in 1955, and the first George Washington class boat was already being built as a Skipjack before it was taken over for construction as an SSBN.
The current SSBN missile is the 58 ton, 44 foot long Trident II. Thus the larger Virginia class SSNs (7,000 tons, 377 feet long) would be spacious enough to have a missile silo section added. This will keep the cost of the new SSBNs down, although the main reason for converting SSN designs to SSBNs in the 1950s was to get the missile boats into service as quickly as possible. For over a decade, the Soviet Union had nothing like it.
November 1, 2004: Normally, a test of India’s Prithvi short-range (300 kilometers) ballistic missile would not draw notice. However, a recent test launch near Chandipur was notable – not for occurring, but from where the Prithvi was launched – underwater.
At present, five nations have ballistic missile submarines: The United States (14 Ohio-class SSBN), Russia (7 Delta IV-class SSBN and 2 Typhoons), France (a total of four SSBNs between the L’Inflexible and Le Triomphant classes – the latter are replacing the former), the United Kingdom (4 Vanguard-class SSBN), and the People’s Republic of China (one Xia-class SSBN). With the successful underwater launch of the Prithvi, India has now cleared a major technological hurdle in its effort to join this club.
Building a SSB or SSBN is difficult. First, one has to be able to build submarines. India has been working on this for a while – with their construction of six French-designed Scorpene-class diesel-electric submarines. One must also have reliable ballistic missiles – India has two in the Prithvi and the Agni. Another problem is to launch the missile successfully from underwater. The last requirement is the most important – submarines rely on stealth. Surfacing to launch a missile is a good way for a submarine to get spotted and sunk. The Prithvi will probably not be the candidate for submarine use due to its short range. Instead, the Agni-II is a more likely component, since its range is comparable to that of the Polaris A-1 (2000 kilometers to the 2200 of the Polaris).
One of India’s last major obstacles to deploying ballistic missile submarines is integrating the underwater-launch technology with a submarine design. One possible candidate is a stretched version of the Scorpene-class submarines India is building. That will only be a first step – the best nuclear deterrence submarines are nuclear-powered, which means they will not only be quiet, but they will never have to surface or snorkel to recharge their batteries. India has to be able to build both those SSBNs and the SSNs to protect them – and that will take time.
Despite those obstacles, India is well on the way to having a portion of its nuclear deterrence force in submarines. – Harold C. Hutchison (email@example.com)
October 24, 2004: The Royal Navy has signed a $145 million contract with the American General Dynamics Electric Boat Division – the builder of U.S. nuclear submarines – to help with the UK’s Astute nuclear submarine construction program. The contract comes on top of two previous contracts worth $52 million to resolve problems in building the Astute-class of hunter-killer submarines. The first boat in the class is four years behind schedule and is now expected to be turned over to the Royal Navy in late 2008. The original three boat order awarded in 1997 is at least a billion dollars over budget and an order for more subs has been delayed until it is clear how much the first three will finally cost.
Officials at BAE, the Astute-class builder, state Electric Boat is filling a gap in British submarine design expertise as well as assisting BAE in getting up to speed in computer-aided design methods and tools. BAE admits they could have managed the work themselves but it would have added more time and money to building the boats. BAE blames the British government in letting UK capabilities in nuclear submarine building decline between ordering the last of the Royal Navy’s Trident ballistic missile subs and the Astute-class. The UK had closed down its own warship design facilities. Said the official, “By the time we needed the designers, they were all on the golf course.” BAE got the “loan” of an Electric Boat executive this year to direct the Astute project.