The governments of Southeast Asia, already fertile ground for defence companies, have embarked on a round of buying submarines, the utility, safety and strategic value of which looks doubtful. In fact, they may actually increase tensions in the region as their lurking menace could swiftly turn a naval encounter from an incident into a crisis.

Singaporestarted it in 1995 by buying a surplus Swedish navy boat, with a further three ordered in 1997, perhaps with designs to manufacture them on license rather than for defense. The first was commissioned in mid-2000 and further orders have since been made as the original boats have been retired.

Malaysia ordered two new Scorpene-class submarines from the Franco-Spanish DCNS/ Navantia consortium in 2002, with the first just having arrived in the country this year.

In late 2009 Vietnam ordered six Kilo-class submarines from a Russian yard,with the first delivery due by 2012. The governments of Indonesia and Thailand are also both considering acquiring new submarines.

However,the growing use of unmanned underwater vehicles, in line with the better-known unmanned aerial 'drones,' is eroding the submarines' raisond'être – particularly as defense budgets are squeezed and technology offers less costly but comparable results.

The economic and technical metrics of operating manned submarines make them among the most expensive weapon in any national arsenal. There are no accurate figures tabulating the capital and recurring costs of submarine programsin Singapore, Malaysia and now Vietnam, including bases and crew training. But in order to keep one submarine operational a minimum of two boats, but preferably three, are needed. Each boat requires two fullcrews – plus support personnel and facilities.

Rough figures for the three navies make acquisition costs alone well in excess of US$3billion, with combined annual running costs unlikely to fall much belowUS$1 billion by 2015, to marginally enhance deterrence of an enemy thatis unlikely to materialize.

The cost-benefit value of conventional submarines – against the perceived value of boats that carry the nuclear deterrence of major powers - is also questionable. Since the end of World War II, Russia, France, the US, Britain, China and Israel together have lost at least 17 submarines in peacetime accidents. Only two have been recorded as being lost in conflicts. Over the same period just three vessels are acknowledged to have been sunk bysubmarines – the Indian frigate Khukri during the 1971 war with Pakistan, the Argentine cruiser General Belgrano by a British boat during the 1982 Falklands conflict and the South Korean corvette Cheonanin an attack by a North Korean mini-submarine in 2010.

Even as the Southeast Asians embark on their buying spree, many countries are reducing the size of their submarine fleets - notably Germany - or have scrapped them altogether, like Denmark. Other European powers are set tocancel or delay new building programs based on economic and strategic assessments.

The attraction of submarines to defense planners lies in their stealth, flexibility and deterrence. A conventional diesel-electric submarine armed with torpedoes, mines and anti-ship missiles and equipped with modern air-independent propulsion systems is aformidable weapon that the most advanced navies have to respect.

Theirprincipal weakness is their high acquisition and running cost, the demands placed on an often limited skill base and their vulnerability within confined or shallow waters. These factors have led most SoutheastAsian navies to concentrate their resources on developing surface forces rather than invest in submarines that offered doubtful strategic or even tactical benefits.

Run silent...

All countries bordering the South China Sea are members of Asean. While manyhave unresolved maritime boundary or territorial issues with neighbors or Asean partners, the likelihood that any of these disputes would move beyond rhetoric and military posturing is highly improbable.

Thethreat from external powers seeking to exert influence in the region isa more realistic scenario, with China and the US able to readily deploynaval forces into the region. But it is inconceivable any regional state would seek to challenge either country to a naval encounter.

...butnot deep

Further, while large areas of maritime Southeast Asia may offer submarines the security of depth and maneuver room, few of them are near main ports, cities or other natural targets for attack or observation. The region's key straits – Malacca, Sunda, Karimata, Lombok, Makassar, Palawan, Balabac, Mindoro, Balintang and Luzon – are either deep but narrow or broad and shallow. They are also unavoidable and therefore dangerous for submarines to transit in the event of hostilities. At least 33 Allied and Axis submarines were lost in the region's seas and straits during WWII. Of the 52 submarines lost by the US Navy during the war, 25 percent were sunk in the South China Sea and Indonesian archipelago. Most were sunk by mines rather than depth-chargeattacks.

Modern anti-submarine technology and weapons have rendered shallow and confined seas exceptionally dangerous. The ability to peer into the depths is forcing submarines into ever deeper waters and reducing their effectiveness in many of their conventional roles. The absence of any clear combat role for the region's submarine forces means they risk being used on operations that can increase tensions among neighbors and notional allies.

For example, protecting sovereignty is far better served by the transparent deployment of surface vessels that can literally fly the flag and negotiate with theiropposite numbers – as occurred between Malaysian and Indonesian patrol boats off Sabah in 2005 and 2009 over a contested oil block. The potential presence of submarines on either side would have further increased tensions and added to the likelihood of dangerous misunderstanding.

Intelligence-gathering and surveillance operations by submarines in shallow littoral waters are also diplomatically fraught. The stranding of a then Soviet submarine close to Sweden's Karlskrona naval base in 1981 proved embarrassing – a similar incident in Southeast Asia could create far deeper problems. Conducting such operations also requires a level of skill and experienceunlikely to be mastered by local crews for years.

Special forces operations are also unlikely to offer a serious rationale within the ASEAN context. The ability to discreetly damage an opponent's capabilities – such as severing key undersea communications links (a feat achieved by British mini-submarines in July 1945 when they cut the telegraph cables between Saigon and Hong Kong with Japan in order to force Tokyo to issues orders by radio that could intercepted and decoded) – may be useful but it is difficult to imagine a situation within the Southeast Asian context when it could used.

Dive stations

Singapore

While Singapore's size, wealth and ethnic composition has been employed to engender a national sense of encirclement requiring modern arms to provide 'total' defence, other motives may have also driven the decision to acquire submarines, probably to build them for other people.

Singapore's security won't be enhanced markedly by the deployment of submarines – the country's large and highly competent air force can readily deal with anypotential incoming threat and the navy's modern surface fleet is capable of keeping any regional opponent at bay. Instead, the acquisition of submarines may fit into the country's industrial strategyof upgrading manufacturing capabilities, particularly in the defence equipment sector.

Singapore's decision to purchase ageing surplus boats from Sweden enabled the navy and the government-controlledSingapore Technologies Engineering to undertake detailed operational and technical studies of them. The skills and knowledge acquired will have been enhanced as newer classes of submarines were ordered. Singapore's shipbuilding industries would be able to build submarines under license within the present decade if the government saw the investment as economically viable.

Malaysia

Malaysia'smotive for acquiring submarines is more contentious. The operational rationale for the two Scorpene-class boats is questionable given the difficult operating conditions for submarines in the shallow waters around the Spratlys and off eastern Sabah. Apart from seeking to match Singapore's naval capabilities, the Malaysian position is that the boatswill be used to protect the country's contested maritime boundaries andclaims. A major naval base has been built at Sepanngar, near Kota Kinabalu in Sabah, to support them.

Another explanation is that the two submarines were acquired with public funds in order to facilitate the payment of huge bribes to a close associate of then defence minister and now Prime Minister Najib Tun Razak. (see Asia Sentinel: Malaysia'sSubmarine Scandal Surfaces in France, 16 April 2010).

Vietnam

Vietnam'sorder for six Kilo-class submarines and fighter aircraft from Russia inlate 2009 has been variously interpreted as show of strength against China and a tightening of bonds with Moscow.

Another view is that the leadership in Hanoi, accused of sacrificing Vietnam's long-termeconomic interests by opening key sectors of the economy to Chinese commercial interests, may be seeking to defend its own position behind the mask of national security. The arms deals, which coincided with the 65th anniversary of the foundation the Vietnam's armed forces and ahead of the 11th Communist Party Congress in 2011, may serve to placate military and nationalist sentiment rather than serve as a realistic deterrent against China's 'hegemonic' ambitions in the South China Sea.

Indonesia

DuringPresident Sukarno's turbulent rule, which ended in chaos in 1965, Indonesia received more than 20 submarines from the Soviet Union, far beyond the country's ability to crew or service. Many never put sea and all were scrapped by the early 1970s. Indonesia has operated two German-built Cakra-class submarines since the early 1980s. One was refurbished in 2006, but the hulls are now nearing the end of their operational lives and they have little strategic or tactical value.

Thenavy has been calling for at least two new boats, but financial constraints and other naval priorities – notably patrol boats able to monitor the country's territorial waters – are likely to ensure any additional acquisitions are stalled by the government.

Thailand

Thailandacquired four submarines from Japan before the Second World War that remained in service until 1951. The navy has been seeking to revive its submarine force over the past decade, to date without success. This partly reflects the army's strong grip on the budget, and possibly the navy's failure to utilise a Spanish-built aircraft carrier commissioned in 1997 but that has since barely left port.

Thailand also facesthe problem of having two coastlines separated by the Malay Peninsula. Adecision would have to be taken whether sufficient boats would have to be acquired that could operate in both the Andaman Sea to the west and the Gulf of Thailand to the east, requiring duplicated support bases andassociated infrastructure of both coasts. The cost would prohibitive and any military gains, particularly in the Gulf, would be minimal if not negative.

G.M. Greenwood is an Associate with Allan &Associates, a Hong Kong-based political and security risk consultancy.