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January 07, 2006

Das Sooper Boot


You're looking at the most sophisticated non-nuclear powered submarine in the world, Germany's new U-212A class. She's lauded on the official German website.

U 212: This cutting-edge propulsion system enables the U212A submarines to move virtually noiselessly underwater, thus making them very difficult to detect.

In the presence of Defense Minister Dr. Peter Struck, fleet commander Vice Admiral Wolfgang Nolting placed into service the newest generation of German submarines in Eckernförde on October 19.

"They represent a milestone in the transformation of our armed forces," Struck said, with an eye to the two submarines docked at Kranzfeld port in Eckernförde. The services are jointly planning to better equip the German Armed Forces for the security challenges of the future. The special capability of the submarines to conduct surveillance in coastal waters illustrates this approach.

The two 212 A submarines are currently the most modern conventional subs in the world. As the only sub type that is not nuclear powered, this class of submarines is driven by air-independent propulsion. The use of fuel cells markedly increases the sub's radius of action. Hydrogen and oxygen combine in the fuel-cell module and are converted into electricity. Water is the only waste product that remains. This cutting-edge propulsion system enables the U212A submarines to move virtually noiselessly underwater, thus making them very difficult to detect.

I served aboard the last diesel-electric submarine in the U.S. Navy, although when I reported aboard the USS Blueback, she was still one of a sizeable -- though rapidly-dwindling -- number of pigboats. The Blueback and her sister ships, Barbel and Bonefish, were the last diesel subs built by the U.S., commissioned in 1958 and 1959. They were the first operational U.S. subs to feature the Albacore-class teardrop hull; the nuclear-powered Nautilus had a modified version of the WWII fleet boat hull.

The older subs were designed with hulls that had a sharp keel and pointed bow, much like a surface vessel, designed to maximize their speed while surfaced. Their submerged performance suffered, with much slower maximum speeds as a result of the increased drag offered by the hull form. This wasn't a significant flaw before the advent of nuclear power, as subs often spent a significant amount of time surfaced, and the advantages, savings in fuel and the higher speeds while transiting the Pacific Ocean, were substantial.

The Navy realized that the Nautilus and its successors were handicapped; although their reactors freed them from the surface -- they could manufacture their own oxygen and water -- their submerged performance was limited by the shape of the hull.

The three submarines in the Barbel class quickly proved the value of the new design. Its wide-beamed, teardrop shape enabled the subs to attain submerged speeds that were significantly faster than had been seen before. The down side was that the surface performance was significantly worse than in the old fleet boats. They were slower while on the surface (not a huge disadvantage as they spent far more time submerged), and, lacking the more stable V-shaped hull, the round-hulled B-Girls rolled from side-to-side with abandon when surfaced.

The Blueback and its sisters also enjoyed other benefits of their advanced design. The Nautilus and its predecessors had two screws, one on either side of the rudder. While they gave the boats the ability to turn on a dime and made maneuvering into port easier, they also doubled the amount of noise and significantly increased drag.

When a screw turns at a certain speed, a vacuum is created along the blades, forming voids -- bubbles. When these bubbles collapse, they make a loud noise. The process, a fast-turning screw creating noisy bubbles is called cavitation. When a screw begins to cavitate depends on both the speed of the blade, the rpms or "turns," and the depth. The deeper the sub, the greater the pressure; the greater the pressure, the faster the screw can turn before it begins to cavitate.

Bottom line: cavitating is noisy. Noise is bad. Noisy subs get killed.

The B-Girls had a single screw, aft of the rudder and sternplanes, which resulted in both less noise (less cavitation) and a smoother hull.

By the time I reported aboard in '81, the nuclear power advocates were firmly entrenched in the Pentagon, and the pigboats were on the way out. Diesel subs were thought to be no threat to the carrier battle groups at the core of U.S. naval theory. After all, the nuclear-powered 688-class hunter/killer subs were protecting the carriers; what could diesel subs do?

Actually, quite a lot. Although diesel-powered subs are tied to the surface in order to recharge their batteries, there are times when they're actually quieter than a nuke boat. The nuclear reactor is essentially a big heating element for a steam kettle. The heat from the nuclear reaction heats water, which becomes steam, which is then used to drive high-speed turbines, which use reduction gears to turn the screw. All that machinery can put high-frequency noise into the water.

Enormous effort was put into isolating all noise-producing equipment from the pressure hull, with rubber mounts and bushings helping to dampen vibrations. Don't get me wrong: nukes are quiet. But let me tell you about diesel boats.

When those three Fairbanks-Morse 38ND 8-1/8, opposing piston locomotive engines shut down, the Blueback began running on its 504 battery cells. They provided 500 volts of DC power to the two massive General Electric motors wound around the propellor shaft. Think about the electric cars you've seen. There's nothing quieter than an electric motor running on batteries.

And in 1981, there was nothing quieter in the U.S. fleet than the USS Blueback running on batteries. Because so many of our potential enemies fielded conventionally-powered subs, we usually played the bad guys in war games.

We routinely penetrated the outer screen of destroyers protecting the carriers, avoided the nuclear subs shadowing the battle group, and got our killing shots off at the massive targets.

As quiet as we were, the Japanese were even quieter. We allowed them access to our Barbel-class boats in a technology transfer; I had an opportunity to visit one of our Japanese doppelgangers when I was in Yokosuka. The Yaeshio-class boat looked identical topside, but when I dropped down the midships hatch and climbed down two decks, I saw that the Japanese had made quite a few changes.

Not as concerned with creature comforts as we were, the interior was much more spartan than on the American boats. It was also the cleanest damn boat I'd ever seen. We cleaned all the time, but the Japanese sub made our boat look like it deserved to be called a pigboat.

The biggest surprise lay in the engine room. When we ran our diesels, the noise in the engine room was deafening; you had to yell to make yourself heard over the racket, even standing right next to someone.

Before my guide opened the hatch from the crews mess into the engineering spaces, he told me that they were in the process of charging their batteries. He swung the hatch open, I ducked through it and looked around, bewildered. It was quiet (and of course weirdly clean); he must have been mistaken.

My guide walked over to a big, white mass and opened a hatch; the noise of an engine filled the space, albeit a very smooth engine. He closed the door and the noise went away, reduced to a subtle hum.

"Sound-encapsulated Kawaskais," he said. "F--k me," said I. They'd put their massive engines into egg-shaped cocoons of sound-deadening material. The Japanese had taken our designs and improved significantly on them.

When we conducted joint operations, we discovered that as quiet as we were, they were like a hole in the ocean. And this was more than 20 years ago.

So, the significance of this German sub? It removes the only real handicap we had, the noise from the diesel engines, and our need to be at or near the surface to operate them, with our snorkel.

Our enemies don't need the ocean-crossing capabilities of nuclear submarines; we're coming to them. What they need is the ability to lay in wait, to maneuver silently, creep into position, and sink our carriers.

Air-independent propulsion systems like the one on the U212A are exactly what they need.

I'm betting the admirals at the Pentagon are worried. They should be.

Posted by Mike Lief at January 7, 2006 09:40 PM


Mike, this is fascinating reading! I'd never heard of any of this.

I just visited Battleship Park in Mobile, AL., and after boarding the Gato-class U.S.S. Drum, I've been searching online for more subs to board.

The U-505 in Chicago is unique in our country, and I haven't been since before it went indoors. I was curious about whether a late-war Nazi Type XXI was anywhere open to the public, doubtless in Europe.

Anyway, I'm glad the search led to your report about this disturbing progress in German submarine technology. Hasn't Germany proven in two world wars that no one should trust them with untersee boots?! Do they deserve a chance at a third strike? This silent new U-boat is baaaad news.

But thanks for the heads-up, for your eloquent writing, and for your service aboard the U.S.S. Blueback!


Posted by: devin meriam at January 11, 2006 08:39 PM

Thanks to the lack of any common sense in our erstwhile allies these classes of subs have been sold all over the world (not necessarily the newest ones).

I agree that in short range operations (any strait or archipelago will do) these would be deadly). For the Germans their coastline is ideal for this.

The US faces the problem of dealing with this threat while maintaining long distance "fleet boat" characteristics.

Posted by: Dave Moelling at January 19, 2006 06:06 AM

Thanks - nice post. I've read for some time about how relatively quiet conventional submarines are but it's nice to read some first hand accounts as well as the strategic implications.

Posted by: John B at January 19, 2006 07:53 AM

Re: Blueback.

It's now parked on (in?) the Willamette River in Portland, Oregon, and you can take a tour - no
disabled accesss, sorry - of it at OMSI (Oregon Museum of Science and Industry).

Since most comments clean out URL's I'll just recommend googling OMSI.

I've taken the tour, and it makes me grateful that I was in the Army.

email is human readable - aloud.

Posted by: bud at January 19, 2006 04:57 PM

If you click on the first mention of the Blueback's name in the article (and here, too), the link will take you to the OMSI/Blueback website.

Posted by: Mike at January 19, 2006 05:38 PM


I am a German and I think you just don't know anything about Germany. We aren't proud about our past, but we are the second generation after the Nazis and we now think very different. We are members in the NATO, the UNO and other peace keeping organisations.

You should better inform yourself before telling this stuff about us.

Posted by: Stefanie at January 24, 2006 09:49 AM

Stefanie, I'm not sure that Mr. Lief is saying that Germany is actively planning the sinking of U.S. aircraft carriers, so much as that the Germans are still very much in the game of submarine design and construction. Your country seems to still be developing world-class technology.

What our Navy ought to be worried about is whether weapons systems which might theoretically pose a threat to our forces wind up in the hands of enemies of the United States.

I have no reason to think that Germany will sell examples of the 212A class to nations of concern, but our admirals would be derelict in their duty to not at least contemplate the mere possibility -- to worry about it, in other words.

If it means anything coming from a stranger commenting on a blog post, I don't believe in visiting the sins of the fathers upon the sons myself, and that dredging up history for which the generation born after the war holds no responsibility is silly.

I hope it's not patronizing to say, your English is sehr gut.

Posted by: Mike James at January 24, 2006 04:41 PM

Mike James --

No need to be unsure; I am most definitely not saying that I believe the Germans are planning to use the U-212 Class against us.

You nailed it when you wrote that the admirals need to concern themselves with sales of this impressive weapons system to third parties, for the Germans (and the Dutch) need to sell ships on the international market to subsidize their shipbuilding industries.

I certainly have no wish to hang the guilt of the two world wars on the current generation of Germans, who seem -- if anything -- to be too unwilling to use their military forces in this post-9/11 world.

Posted by: Mike Lief at January 24, 2006 05:15 PM


You may be interested in the group of submarine milbloggers who band together at Ultraquiet No More. There's a good-sized group of them there. And now I have to figure out a way to add you to the map!

Two points:

--The Germans have not only an aggressive export program but also a package deal: comes with operator training and more. I worked with a country that bought theirs like this: first one built in Germany, next one assembled locally, third and follow-on indigenously constructed using the designs. Worked pretty well and beat the Russian offer for Kilos.

--Diesels with AIP have gotten ludicrously quiet and if you need a manned, intelligent floating mine or a small surveillance/insertion platform then it's the thing to buy. The one thing a diesel cannot do, of course, is endure. It can't run around all the time, can't go flank for a couple of hours then sit there for a week or two, and definitely can't race across the Pacific and then sit on station for many months without so much as a by-your-leave. That's the big killer for us, but others don't have as much of a concern about that restriction (like Singapore).

Posted by: Chap at January 30, 2006 05:34 PM

Why am I reading that the new Chinese Yuan-class sub look remarkably similar to the 212A's. And its public information that Israel, India and Pakistan are buying the German subs too.

Posted by: Cory at May 27, 2006 08:42 PM

And the 212 Class has made even more tech advances. Lithium-ion battery development to enhance endurance; a new command and control suite; further signature reduction. There's even a new submarine launched SAM under development.

Peter Hauschildt's "U-Boats Made in Germany: German Submarine Technology Today and Tomorrow" has just been published in English. Its got the latest scoop on German submarine tech. But its only available for Kindle.

Posted by: Jack at October 23, 2010 06:15 PM

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