February 6, 2018: In early 2017 the first Indian designed and built nuclear powered submarine, the 5,000 ton SSBN (ballistic missile carrying sub) INS Arihant finally completed another round of tests and was declared in service. Shortly thereafter parts of the sub were flooded because, as the navy put it, someone left a hatch open (or failed to close it properly) and seawater got into the boat. It was reported that ten months of repairs were required to deal with the saltwater damage. It is unclear if the Arihant is back in service, or ever will be.

This comes after three decades of planning, numerous revisions and technical failures, construction and delays in getting all systems functioning at the same time. It started when India began working on a SSN (nuclear attack sub) in the late 1980s but as work progressed it was decided to enlarge SSN design by adding a ballistic missile compartment and put all their efforts into creating an SSBN. This was a tried and true solution. Russia and China had successfully done this, following the example of the United States in the 1950s.

The first American SSBNs were the five, 6,000 ton boats of the George Washington class. These were basically Skipjack class SSNs that were enlarged to add the missile compartment (for 16 Polaris missiles.) The 3,000 ton Skipjacks were designed in the early 1950s and construction of the first one began in 1956 (and entered service in 1959). The U.S. Navy literally modified the hulls of two Skipjack SSNs under construction to accommodate the missile compartment and other less drastic changes. Thus the construction of the first American SSBN began in 1957, was launched in June 1959 and entered service at the end of 1959. Four more followed and by March 1961 five of these SSBNs were in service. They all served into the 1980s. The first American SSBN class was followed by five of the 6,900 ton Ethan Allen class, which was designed from the start as an SSBN. The first of these began construction in late 1959 and entered service in August 1961. Four more followed by January 1963. Note that the first American SSN (the Nautilus) began construction in 1952 and entered service in 1955. So the U.S. Navy went from SSN to SSBN in four years. Why has the Indian Navy taken so much longer to get it done? Apparently Arihant is still not in service. Meanwhile a second Arihant class SSBN was launched in late 2017 (construction began in 2010) and is supposed to be ready for sea trials in late 2018. Maybe, perhaps or whatever.

Arihant was supposed to enter service before the end of 2015 but there were more unforeseen technical problems to fix. Nevertheless Arihant was commissioned as a navy ship in August 2016 even though it had not carried out its sea trials. These commenced in late 2016 and were declared successful. Apparently Arihant has yet to carry out a “combat cruise” (with nuclear armed missiles) to within range of potential enemy targets.

Arihant was launched in 2009 but completing the sub was delayed again and again because of new problems showing up. Nevertheless the success of Arihant led to an SSN (nuclear attack submarine) program, which is now underway. In 2015 India announced ambitious plans to build six SSNs but admits development and building will probably take at least fifteen years. One locally made nuclear sub doesn't change the balance of naval power much for India, which is already dominant in the region but it does show that India can build nuclear subs and six SSNs will make a difference. Two more Arihants are under construction and two more planned.

Meanwhile in March 2016 India successfully tested its new K4 SLBM (Sea Launched Ballistic Missile) under realistic conditions. This consisted of a submerged silo (like the one used in a submarine) that successfully released the missile at a realistic depth. The missile reached the surface, ignited its rocket motor and completed its ballistic flight as it was designed to do. Several more successful tests like this are required before K4 can enter service. K4 is based on the Agni 3 land based ballistic missile, which has been in service since 2010. Both the Agni 3 and K4 have a range of 3,500 kilometers. K4 is a 20 ton, two stage, solid fuel missile that carries a one ton warhead.

Arihant was built to carry nuclear armed K4 or K15 ballistic missiles designed and manufactured in India. Arihant has four vertical launch tubes, which can carry twelve (three per launch tune) of the smaller K15 missiles or four larger K-4s. The Arihant is based on the Russian Charlie II sub, which it resembles. The Charlie class had eight launch tubes, outside the pressure hull, for anti-ship missiles. Arihant has a crew of 90-100 and six 533mm (21 inch) torpedo tubes in addition to the four vertical missile launch tubes.

In early 2013 the K15 missile underwent its final development test and was ready to be installed in the Arihant. This came after five years of testing and tweaking. In 2007, India announced that it had perfected the technology for launching ballistic missiles from a submerged submarine. That meant the silo design had been perfected as well. In 2008, India began a series of twelve test firings from a missile cell designed to fit into the Arihant. These test firings were not done from the Arihant but from the cell placed in the ground or underwater to simulate launch from the sub. Seven launches took place in 2008.

The seven ton K15 has a 700 kilometer range with a one ton warhead or 1,900 kilometers with a 189 kg warhead. The latter weight is sufficient to handle a nuclear warhead if India has been successful in developing warhead technology to the same point the U.S. and Russia were in the 1980s.

The first SLBM was the U.S. Polaris A1, which entered service in 1961 after about five years development. Like the K15 it was a two stage solid fuel missile. The Polaris A1 weighed 13 tons, had a range of 2,200 kilometers and a one ton warhead.

There are apparently problems with the readiness of the nuclear warheads used in the Arihant SSBNs. This has to do with security and controls over who has launch authority. This subject has not become a news item yet but it is another reason why the Arihant is not really “in service.”