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Naval Forces 

Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance 


By Grace Jean  

Anti-Sub TechnologyThe Navy in recent months has had to contend with several provoking episodes at sea — Iranian small boats speeding at its cruisers, destroyers and frigates; Russian bombers flying over its carriers; and Chinese subs shadowing its warships.

Hard-to-detect submarines — such as quiet, diesel-electric boats — are particularly vexing, Navy officials say. They contend that an undersea arms race already has begun in the western Pacific.

Nations there in recent years have begun to acquire stealthy diesel-electric submarines. Some of those nations, say Navy officials, could one day threaten U.S. access to strategic coastal areas of the world or interrupt the flow of commerce around the globe.

Although the Navy has the world’s most technologically advanced fleet — including state-of-the-art nuclear attack submarines — officials acknowledge that these comparatively low-tech diesel-electric boats could give an enemy an asymmetric advantage.

“The beauty about a diesel submarine is that it has the potential to be far quieter than a nuclear submarine,” says Guy Stitt, president of AMI International, a Bremerton, Wash.-based company specializing in naval market analysis. Diesel boats are propelled by batteries when submerged and move through the water by diesel engines when on the surface.

Once they have powered up their batteries, the submarines can sail to the bottom of coastal waters and remain undetected for days. Though they can’t travel long distances or sail very quickly, advancements in technologies, such as air-independent propulsion and fuel cells, have allowed diesel submarines to extend their operational ranges underwater.

But perhaps their best selling point is their relatively inexpensive price tags. The Russians have sold diesel submarines for as little as $200 million and the French have exported their Scorpene submarines for $300 million.

“It is within the scope of many, many countries to be able to afford them. They don’t need a lot of them. They don’t need to sail them very far, and they don’t have to be particularly proficient with them,” says Vice Adm. Samuel Locklear, commander of the Navy’s Third Fleet, which prepares strike groups to deploy to the Pacific and the Middle East.

More than 39 nations possess diesel submarines. One of the latest tallies indicates a total of 377 ships in the world, says Richard Dorn, an analyst at AMI International. And there could be an uptick in the next few years.

With China continuing to increase the size of its navy, a number of neighboring nations also have begun to develop their undersea capabilities.

“There’s a push on in Asia that really seems to be driven by China,” says Stitt. Singapore, Malaysia and Indonesia all have closed deals on diesel submarines, and now Thailand is following suit.

Driving the market in part is Russia, which during the past 18 months has been aggressively selling ships, including its Kilo-class diesels.

“We’ve seen a huge increase in the number of sales that they’re booking for Kilos, primarily motivated by the need for funds to strengthen their second tier shipbuilding groups,” says Stitt.

Since the end of the Cold War, Russia has lost many of its secondary shipyard suppliers — the engine, pump and valve manufacturers, piping companies and the like. But Russia is attempting to revitalize those small companies.

“They’re going out and making all these deals to sell submarines and ships and using those funds to reinvigorate the industry, which in turn will also benefit them in building up the Russian fleet,” says Stitt.

Russia has exported 30 Kilos around the globe and 26 are still in active service. It will deliver two more submarines to Algeria by 2010, five to Venezuela by 2020, and six to Indonesia by 2018. China received its 12th and final Kilo last year.

The number of Kilos that are being sold is particularly concerning because many of the submarines are equipped with Klub anti-ship cruise missiles.

Some nations have a desire for regional hegemony and want to strengthen their influence in an area. That’s most definitely the reason for President Hugo Chavez buying subs for Venezuela, says Stitt.

But for other nations, the reasons are less clear.

“There’s a wide array of military assets you can buy, so why would you buy a diesel-electric submarine? As far as I know, it’s not to protect your own port,” says Locklear in an interview at Third Fleet headquarters perched atop Point Loma in San Diego.

That China’s submarines are surfacing boldly near U.S. warships is a telltale sign of newer advanced technologies, such as acoustic tiles and cavitation-reducing propellers, that are being employed on the submarines, says Stitt.

China’s new Song-class diesel submarines have tracked U.S. Navy ships operating in the seas near Japan and Taiwan. Last November, after China denied the USS Kitty Hawk’s port call in Hong Kong at the last minute, a Chinese submarine shadowed the carrier as it entered the Taiwan Straits on its return voyage to Yokosuka, Japan. In the late fall of 2006, a Song-class submarine surfaced within torpedo range of the Kitty Hawk off the coast of Okinawa, Japan.

Despite the tensions, those episodes and the topic of submarines did not come up directly in conversations with Chinese officials in January, when the commander of Pacific Command, Adm. Timothy Keating, visited the nation.

“We watch them carefully. It’s an area of warfare at which they’re stretching a little bit,” he told reporters during a breakfast meeting in Washington, D.C. “Their numbers of submarines are increasing. The capabilities resident in those submarines are not unimpressive. They’re pretty good — we’re better.”

China’s fleet of nuclear and diesel submarines includes 10 Song class, 12 Kilo class, one Yuan class and 32 Romeo class.
“We know that they are continually expanding their reach in what they view as their own areas of interest, and that their submarine force is vital to expanding that reach,” says Locklear.

The proliferation of diesel submarines in the Pacific is one of the major factors behind the Navy’s decision to move six submarines from the Atlantic Fleet to the Pacific Fleet, says Rear Adm. Joseph Walsh, commander of the Pacific Submarine Force. Because more than 140 diesel subs are within reach of critical “choke points” in the area, anti-submarine warfare is Pacific Fleet’s top war-fighting priority, he adds.

The Navy saw its anti-submarine warfare skills diminish after the end of the Cold War. In those days, enemy Soviet nuclear submarines were noisy, and could be detected with passive sonar.

But modern-day diesel submarines are not as easily heard, particularly in regions of the seas where biological life and merchant shipping can camouflage their acoustic signatures. It is there, in the noisy waters of the littorals, where detecting submarines can be a cat-and-mouse game, Navy officials say.

Rear Adm. John Waickwicz, who was the head of the Naval Mine and Anti-Submarine Warfare Command until he retired in January, says the Navy is looking at anti-submarine warfare in new ways.

“When you talk about countries that have 30, 40, or 50 submarines, you can’t wait until they’re around you, because they’re going to overwhelm you,” he says.

Potential enemies have figured that to defeat the U.S. Navy, they must “go out and buy submarines, and buy mines,” he says.

The mine and anti-submarine warfare command is calling for the deployment of a network of sonobuoys over a wide expanse of ocean to detect enemy submarines. But the project has been marred by technological and funding problems. The most significant hitch is that the data collected by the sensors takes too long to analyze, says Waickwicz. “You need to do it in real time to take action on it.”

False alarm rates on many of the fleet’s current detection technologies are too high, Waickwicz adds. That forces commanders to waste resources on non-existent threats.

Officials insist that the Navy’s anti-submarine warfare capabilities are the best in the business, but they acknowledge that it will take some time to hone the skills to combat stealthy diesel submarines. Waickwicz says that training has improved in recent years, but some individual units are not adequately prepared for at-sea operations.

For example, some units have demonstrated sonar operator proficiency on simulations that are not sophisticated enough to replicate the real environment, which puts the sailors at a disadvantage when they conduct operations at sea, says Rear Adm. Frank Drennan, the new commander of the Naval Mine and Anti-Submarine Warfare Command.

“The requirements are still the same — they just have to work on them in a challenging environment so that operators are truly proficient when they go to sea,” he says.

Hunting for quiet diesel submarines in the shallow waters of the littorals is akin to trying to identify the sound of a single car engine in the din of a major city, he says.

There are variations in the underwater topography, with sand bars, coral reefs and channels. Different depths of water and changing salinity and temperatures alter how sounds propagate. Marine life and merchant shipping also complicate the search by generating ambient noise.

The only technology that the Navy considers suitable for detecting and tracking diesel submarines is active sonar. It disperses signals out into the water where they bounce off of objects. Those echoes are captured by hydrophones and interpreted by sonar technicians.

Contrary to popular belief, sonar is not like radar, which gives complete visibility of “hits” in the air. What sonar technicians see is a screen that is filled with vertical lines representing echoes from objects in the water. Discerning which line is a submarine and which one is a coral reef is a difficult and complex task, sailors say.

The Navy spent 40 years building a training range on the coast of Southern California — one of the most extensive in the world, officials say. Underwater sensors track ships’ locations and record operations during exercises.

Because the water and ocean bottom conditions are representative of many areas around the world, the range is an ideal location for training strike groups in anti-submarine warfare, says Locklear.

But the Navy’s training there has been curtailed by ongoing litigation over the harmful effects of active sonar on marine mammals.

Under a federal judge’s ruling, ships were forbidden from using active sonar within 12 nautical miles of shore and had to steer clear of waters between the Santa Catalina and San Clemente islands during a joint training exercise in January for the Abraham Lincoln carrier strike group. Sightings of marine mammals at certain distances also prompted ships to take protective measures, such as powering down sonar or shutting the sensors off completely.

“We’re not able to employ the sonar, given those restrictions, in a realistic manner, and it just makes it real tough to assess whether the fleet is proficient at using the technology,” says Capt. Pete Tomczak, deputy director for training at Third Fleet.

The use of sonar by the Navy has been linked to mass marine mammal strandings on beaches in the Bahamas and the Canary Islands. Pending necropsy results, the death of a northern right whale dolphin that washed up Jan. 29 on the Navy’s San Nicolas Island could be connected to sonar use.

Locklear says the Navy tries to balance its responsibility to protect the environment with its job to prepare sailors for war. He expresses concern that the judge’s ruling, if extrapolated beyond Southern California, could hamper Navy training around the world.

“If this becomes precedence setting, I think it will be very difficult for the United States Navy,” he says. “If there was a new technology on the horizon that made this irrelevant, we would be all over it. We just haven’t found it yet.”

With prospects of at-sea training diminishing, not only because of the litigation, but also as a result of rising fuel costs and other budget constraints, the Navy is searching for alternative ways to prepare its sailors for anti-submarine warfare.

One option is to rely on simulators, says Waickwicz. But he points out that current simulations in the Navy do not replicate sonar accurately.

“It’s like playing ‘Pong’ in today’s game world,” he says. While the submarine forces have higher fidelity trainers, much of the rest of the fleet — especially surface ships — have sub-par simulations.

“Computer simulations can only go so far. There is still no substitute for at-sea practice against a real submarine,” says Pacific Fleet’s Walsh.

Because the U.S. Navy no longer operates diesel-electric submarines, it invites allied countries that own these boats to participate in exercises at Navy ranges on the east and west coasts.

The Swedish Navy’s HMS Gotland collaborated most recently with various Navy commands in San Diego.

“It was very advantageous to have a diesel submarine crew for two years, to see how they thought, how they approached the issues to go against the ships,” says Waickwicz. “It really opened our eyes to diesel submarines and how active sonar is what you have to have in the strike group.”

The experience led to recent changes in the Navy’s anti-submarine warfare doctrine and tactics.

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Reader Comments

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

The reason the USN doesn't have diesel subs is because their submerged range is far too short. The USN needs to be able to project power anywhere in the world, not just defend the coasts. Most countries are only trying to defend their coasts, and diesel subs are well suited to this task. Their advantage in stealth over nuclear submarines is only when they are submerged and operating on battery power. But they cannot go far when submerged. It would be a waste of money for the USN to buy diesel subs, especially when we can train with the diesel subs of friendly nations like Sweden.

Felix on 08/04/2016 at 12:17

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

The German U-Boats of WW II, wreaked havoc for the early early years of the war. While they were killed by American and British sub hunting Destoyers, they were found by aviation assets. Our navy has the S 3 viking and the P-3 orion as well as a massive satelite surveilance capability. Diesel subs have to surface to breathe, if a shooting war breaks out they will take their last breats because of that shortcoming. The Alliede forces of the world will play whack a mole with them. Unfortunately they will inflict damage to our fleets before they are killed.

Dan on 12/31/2012 at 13:04

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

When our son was assigned to the Houston I reminded him that diesel boats were very quiet and difficult to detect. Run silent, means just that-silent! After 2patrols he agreed. I was a smoke boat Engineman. Had a handle on silent service.
We could hear any Nuke comming or going. Our Navy needs some diesel boats.

Alec McArthur on 10/31/2012 at 19:32

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

The US Navy's LATEST annoyance? Have they forgotten this?;

...or this?;

...or lots and lots of this?;

It sounds an awful lot like the way the US Navy suddenly realized that mines are a clear and present danger...;

...which they've been repeatedly warned of for several decades, but militantly ignored;

Mines were a mystery to the Navy back in the Gulf War too, when the USS Princeton and USS Tripoli (ironically, the flagship of the counter-mine task force) hit mines --- even after the mine strike on the USS USS Samuel B. Roberts in 1988 meant that they saw it coming.

In short, don't expect the US Navy to "get it". All the warning signs in the world won't penetrate a thick skull... but Admirals who can't address (let alone CORRECT) a clear and present danger can always be replaced with those who can. That's why there was a favorable outcome to the last war the US Navy won that it was involved in --- World War 2.

Blacktail on 09/24/2012 at 03:52

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

I'm kinda curious..Would it not be advantageous to us if we claimed that we could not detect them, when in truth we can? Truthfully, I would not want the "enemy" to know I can see them when they believe I cannot... Just a thought.

George Wright on 09/22/2012 at 11:35

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

This was pretty thoroughly covered in the movie "Down Periscope" back in 1996. Strange how Hollywood (in a comedy, no less!) anticipated the reality of 2012. Empires are often found to have feet of clay, ours included.

Michael Arrowood on 07/29/2012 at 01:33

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

The Chinese are not going to care about some ridiculous Lib-Dim concerns over sonar's effect on wildlife as they sink our subs and carriers! The needs of the Navy, training our anti-submarine warfare units should trump any wildlife concerns cause if we get into a war with the Chinese or anyone else with sophisticated submarines we will need the ability to detect those subs quickly

Abaddon on 05/31/2012 at 16:07

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

The US Navy does not have the most technologically advanced fleet. That is the Royal Navy, with the most advanced destroyer in the world, the Daring-class, and the world's most advanced attack submarine, the Astute-class. Not to mention world-beating surface ship systems and weapons.

Morg20 on 05/03/2012 at 03:29

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

All things old are NEW again. Had no idea this
was going on. Finally a case where operator
expertise and years-of-service trumps computer
models. Suggest you contact all submariners
from WW II and work as a team toward this goal.

Anon. Reader on 04/14/2012 at 22:17

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

Over reliance on Nuclear Submarines contradicts the strategic principle that military forces should be strategically and tactically integrated to maximize strategic and tactical offensive and defensive operations. A combination of nuclear and modern diesel submarines would enhance the same. The Sicilian defense in a game of chess begins with merely a pawn placed at C5. Thus, merely efficaciously placing diesel electric submarines strategically and tactically may prove more advantageous than utilizing nuclear submarines.

C.V. Compton Shaw on 02/18/2012 at 14:04

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

I stumbled on this article while trying to find the last USN diesel sub. My compliments to the author for an informative yet somewhat alarmingly concise article. Unlike the previous response, I don't share his confidence in a world where political realities have shown how quickly allegiances can change. Maybe this is a naive suggestion, but why don't we build our own diesel sub fleet? Do we not have mothballed subs that could be re-commissioned? The cost benefit of more low cost subs to fewer nuclear subs seems like something to consider. Just my thoughts,for what they're worth.

John Green on 11/11/2011 at 21:00

Re: Diesel-Electric Submarines, the U.S. Navy’s Latest Annoyance

Am still pretty confident about the Navy`s sub/anti-sub warfare forces`ability to fight and win against any type of foreign sub, be it diesel electric and/or nuclear. Of course it would NOT be a bad idea if the US NAVY also bought a few dozen of the best diesel electric subs from Europe. The more variety our Navy has, the better.
If our target is a South American navy, no problem. If its the Chinese Navy, we have some work to do but am sure we`ll get it done right with a little time, luck and realistic training and improved technology and first-class leadership & discipline.

Fred Collins on 04/25/2011 at 16:05

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