Modernisation of the PLA(N) Submarine Fleet – Gaps in the Capability

There has been a lot of discussion over the past five years regarding the rapid and impressive build up of the PLA(Navy). They have added new classes of frigates, destroyers, submarines, amphibious ships and even their first large aircraft carrier is now conducting her sea trials. Ostensibly, this is a navy on the move. These are the clear signs of a nation undergoing an economic evolution unprecedented in its history. China, traditionally an autarky, must now trade with the rest of the world. China has gone from a net energy exporter in 1990 to a major energy importer now, and domestic sources are not able to cope with ever-increasing demand for energy. In 2010, Chinese oil imports passed 5,000,000 barrels a day.

27th Apr 2012


 China

 Modernisation of the PLA(N) Submarine Fleet – Gaps in the Capability

 Mark Farrar / Canberra

There has been a lot of discussion over the past five years regarding the rapid and impressive build up of the PLA(Navy). They have added new classes of frigates, destroyers, submarines, amphibious ships and even their first large aircraft carrier is now conducting her sea trials. Ostensibly, this is a navy on the move.

These are the clear signs of a nation undergoing an economic evolution unprecedented in its history. China, traditionally an autarky, must now trade with the rest of the world. China has gone from a net energy exporter in 1990 to a major energy importer now, and domestic sources are not able to cope with ever-increasing demand for energy. In 2010, Chinese oil imports passed 5,000,000 barrels a day. Coal imports rose to 200,000,000 tons in 2011 and her liquid natural gas imports exceeded 12,000,000 tons in the same year. Her financial health depends on China being able to conduct a healthy and growing export trade, and on an equally healthy raw materials and energy import trade.

So the PLA(N)’s expansion is being driven by an obvious strategic requirement. The Chinese economy is now dependent on maritime trade for the first time in Chinese history. The logic is inexorable, China now requires a substantial navy to protect that new maritime dependence, and she is building one. The focus of this Navy must be the South China Sea and its southern gateways to the Indian Ocean.

But building a navy and developing a capable navy are two very different matters. Naval skills are complex and delicate things, difficult to develop, easy to lose. The Chinese are attempting to develop several major maritime warfare skill sets simultaneously.

One of these is submarine warfare. The PLA(N) has had a large submarine force since the 1960s, so on the surface this should be an easy skill set to further develop. After all, they have three naval generations of expertise. The PLA(N) is aggressively building submarines with the Song and Yuan class conventional submarines in serial production.

Current PLA(N) Conventional Submarine Numbers
Type 035 Ming class submarine - 17
Kilo class submarine - 12
Type 039 Song class submarine - 20 (final vessels under construction)
Type 041Yuan class submarine - 2 (more under construction)
Improved Yuan class - 0 (at least two boats under construction)

The trouble with rapid capability build-ups in several areas simultaneously is that it is easy to build many mediocre platforms quickly - meaning potential block obsolescence. It is also very difficult to make them capable against the new peer opponents that such a build up is intended to match.

And here the PLA(N) is showing severe stress. Recent high level assessments regarding the rapidly modernising PLA(N) submarines force is illustrating the nature of these stresses and the capability gaps they have created.

To obtain the open-ocean expertise the new conventional submarine force must have to meet its potential foes, the growing fleet of around 60 modern-looking submarines must conduct more patrols. They must conduct patrols to signal both developing naval competence and increasing capability to influence events inside the second island chain. Yet this is a double edged sword.

As recently as 2005-2007 the PLA(N) submarine force rarely did more than very basic daily training in shallow water exercise areas immediately off their bases. This training was fully scripted rote-work, indicating little understanding of their art and no mastery of it. The PLA(N)’s conventional and nuclear powered submarines managed no more then seven actual patrols in 2007. In 2005 it was one. Each of these patrols was detected and in each case the submarine was shadowed by Allied submarines (both conventional and nuclear) which gathered acoustic intelligence (ACINT) on them. There are unconfirmed reports of a submarine obtaining a ‘sublook’, getting so close that video footage was obtained of the Chinese vessel. If so, then this is remarkable, for this procedure is so hazardous and demands such a high level of professional skill that very few submarine commanders can achieve it.

While the PLA(N) submarine force operated in daylight in the coastal shallows near their bases, their actual, capability could not be known. ASW aircraft, surface ships, SOSUS arrays and submarines could not be used in these waters. What the ocean patrols did was start to reveal the true capability of PLA(N) submarines – and it was anything but flattering to the PLA(N). By far their best submarines were the Russian-built Kilo class, and these were export models far noisier than the parent navy’s own Kilo class. The Chinese crews had poor noise discipline and frequently made mechanical transients. This demonstrated a poor acoustic culture in their submarine arm and poor tactical understanding in their officer corps. Submarines are most often located by passive means – by listening for them. The more noise the submarine makes the easier it is to find, and once located, a noisy submarine is easy to attack.

The US Office of Naval Intelligence had little information to go on and so was conservative. Their estimates placed the PLA(N) about a decade behind the state-of-art for Russian submarines and so about two decades behind the USN. These estimates were proven to be very conservative, the real picture is much worse for the PLA(N). Once the PLA(N) had its newest submarines patrolling out-of-area more frequently into the South China Sea, east of the Ryukyu islands and into the Philippine Sea, tracking has revealed much about them which was previously unknown.

Out-of-area patrols means that the true masters of the art, the USN submarine force, Japanese submarine force and Australian submarine force are much more able to locate and track PLA(N) submarines. This generates the most closely-held intelligence data, acoustic intelligence or ACINT. ACINT is the crown jewel of naval intelligence. It is very difficult to obtain, perishable and uniquely valuable for what it reveals of genuine capability. A submarine is valueless if it is noisy.

The PLA(N)’s new submarines are noisy. Noisier than previously assessed. They radiate loudly in some of the frequency bands most dangerous to a submarine and appear to be ‘noisier than they really should be.’ Contact was made with civil experts in submarine radiated noise, and a very interesting picture has emerged.

Away back in the 1990s, the Chinese covertly approached German submarine diesel engine manufacturers with a request. They wanted to purchase one shipset of ‘the quietest and most advanced German submarine diesels’, and they offered hefty bribes to obtain them. The Germans realised the modus operandi of course. The Chinese wished to buy a shipset and reverse engineer it, their usual method of intellectual and commercial property theft.

The stage was set for a classic sting operation with long term strategic outcomes. Available information is sketchy, but suggests that the Germans contacted the USN about the Chinese approach. This resulted in a plan of action being worked out with various agencies but including the USN’s submarine force and the Office of Naval Intelligence’s specialist submarine experts. The Germans reacted as the Norwegians did when selling highly classified propeller designs to the USSR back in the 1980s. They initially refused, but then ‘cracked’, saying instead they would consider a larger order, with larger bribes, if the Chinese would specify the levels of acoustic performance they wanted. The Germans would then build engines to this specification – for a price.

The Chinese fell for it. After much covert negotiation, they put together what they thought was an acoustic requirement at what they thought was the ragged edge of the physically possible. The German company received this with expostulations of how very difficult it would be to achieve the very demanding standard the PLA(N) had set.

What the Chinese had revealed was their understanding of state-of-the-art in radiated noise levels in submarines. The USN and Allied navies were delighted, and the Germans were ‘laughing fit to bust’ according to professional contacts. What the Chinese thought was a very demanding acoustic radiated noise level was indeed state of the art – for 1970. The Chinese had revealed a crucial and long term strategic weakness, one fatal to their submarine force in any conflict.

The German reaction was to pull diesels off-the-shelf. These engines are variously reported as standard basic spares or refurbished old engines of the vintage fitted to early model Type 209 class submarines.

These were engines 25 years behind state of the art, with little more than mid-late1960s acoustic rafting and isolation systems. These were delivered to the Chinese very quietly, as befitted such a ‘technological coup’ by the PLA(N). The Chinese immediately set about copying the acoustic quietening systems and reportedly experienced much difficulty in doing so. The first few Song class are reported to be much noisier than expected with the information which could be obtained from the systems supplied. They have since improved and now meet radiated noise levels to be expected from early 1970s submarines.

As a result of this operation, the PLA(N) has locked their highly specialised acoustic systems design teams into obsolete technological approaches. They have also mostly wasted two decades of development time and the considerable resources that went with it.

The result is a large number of brand new PLA(N) submarines which can be passively detected in the first convergence zone, an annulus (or ring) often about 20-30 miles from the submarine. It is the zone where the acoustic refractive properties of deep water ‘bring the sound of the submarine to the surface’ of the sea where a surface ship or shallow sonobuoy can detect it.

During the Cold War, the noisy Soviet submarines were commonly detected in the first, second or even third convergence zones. However, improvements in Russian acoustic quietening made convergence zone detections gradually fade from possibility.

The USN is now making convergence zone detections on Chinese conventional submarines. Their nuclear submarines are much worse, perhaps fifty years behind state of the art, barely better than the first production generation of USN nuclear submarines.

The PLA(N) has no choices left. They must stay with their current submarine designs, and that means they are in a trap from which escape will be both difficult and very expensive, unless they can penetrate the most carefully guarded western military technological secrets.

Make no mistake, this is a war-winning advantage. In any future war, USN nuclear and and Allied conventional submarines should be able to impose heavy losses on the PLA(N) submarine force in open waters. Chinese submarines will not be capable of interdicting Allied submarines, opening their surface fleet to unsustainable loss levels and opening China’s coasts to submarine launched land-attack missiles. There has been a notable slowdown in Chinese submarine launching rates in recent years, and this may be explained by their growing awareness of the vulnerability – indeed the obsolescence – of their new submarine types

The situation also has significant effects on the Pacific balance of power. The U.S. Navy had a massive technological advantage over the PLA(N) even before the rise in Chinese submarine patrols revealed their true capability. Now, the value of the PLA(N) submarine force outside noisy and shallow coastal waters has been significantly reduced.


 

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