Keeping the blogosphere posted on the goings on of the world of submarines since late 2004... and mocking and belittling general foolishness wherever it may be found. Idaho's first and foremost submarine blog. (If you don't like something on this blog, please E-mail me; don't call me at home.)

Tuesday, June 12, 2007

Joe Buff On The Nuke Vs. Diesel Debate

Submarine author Joe Buff has a good discussion up at (a re-print of an article the originally appeared in USNI's Proceedings, whose current issue features a spotlight on submarine warfare) on the question of whether or not the U.S. should build diesel submarines. Some excerpts:
Proponents of acquiring diesel subs argue that because an SSI is smaller and requires less sea clearance than a nuclear boat, it can penetrate far closer to shore without risk of bumping its nose, dragging its tail, or breaking the surface unintentionally. In reality, however, the differences aren’t that great. The typical SSGN is only about 25 feet higher than a diesel-propelled SSI, and for the Virginia-class SSN the disparity is only some 15 feet. Moreover, the question of how much clearance is acceptable for a particular class of sub depends more on a vessel’s ship-handling and stability than on the size of the boat itself. Submariners say the key to operating safely in littoral areas with a large sub is simply to move slowly.
What is more, the ability of nuclear boats to operate closer to shore can be improved by equipping them with minisized unmanned undersea vehicles or autonomous undersea vehicles (UUVs or AUVs). They can be used as remote robot sensor probes, enabling crew members to scout ahead and combine their survey of on-the-spot conditions with satellite data on local sea characteristics.
Contentions that nuclear-powered subs are less maneuverable than diesels are similarly flawed. Virginia-class subs are equipped with a new computer-controlled autopilot and hovering system that enables them to maintain a specific depth to within one-tenth of a foot and to remain perfectly level in any but the roughest seas. Thus, they can penetrate close to shore wherever the contours of the sea floor permit. Ohio-class SSGNs -- onetime SSBNs that have been converted into SSGNs -- also are very stable. In their former incarnations, they had to be able to fire sub-launched ballistic missiles (SLBMs) over thousands of miles with pinpoint accuracy and recover quickly from each jolt to be ready for another possible launch. As the Ohio-class subs are overhauled, they receive hovering and trim systems enhancements...
...It is also a misconception that submerged, non-snorkeling SSIs can run at their top speeds for long periods. When a diesel submarine accelerates to sprint speed, it draws power from its regular batteries. Once the batteries go flat, the AIP equipment of an SSI’s propulsion system permits cruising at only a few knots. If the captain wants to use the AIP system to recharge his batteries, his speed is even more restricted for quite some time. The reality is that it limits the range of the SSI, making it easier for an enemy nuclear sub to pursue and destroy the diesel. If the pursuing nuclear boat gets into trouble, its superior mobility and its wider array of available countermeasures (and burgeoning arsenal of “stand-and-fight” weapons such as sub-launched anti-air Sidewinders and anti-torpedo torpedoes) will enable it to defend itself if necessary, withdraw to deep water and later repenetrate the littoral area at a more opportune time. While an SSI must use its fuels carefully and recharge its batteries frequently, a nuclear boat can recharge its minivehicles (its UUVs and AUVs) indefinitely.
Read the whole thing. (You can also read Joe's other essays here.) I agree with Joe that lowering ourselves to the technology level of our potential adversaries isn't a smart move, but I would add one thing. Joe says that diesel subs can be built for 3 to 5 times less that nuke boats, but I'm thinking that when you add in all the SubSafe and fancy coner gear that U.S. subs really can't do without, you'll find that an American diesel boat would come in costing more than half of what a Virginia costs. And personally, I'd rather have one SSN than two AIP diesel boats if I was in a fight -- speed is life.

Bell-ringer 1115 12 June: Jim C. wrote more about this topic back in November.


Blogger Jim C said...

Great posts after your last one like this I had some related thoughts on the tactical, strategic and economic comparisons. I wasn't quite as polished though.

6/12/2007 11:07 AM

Anonymous Anonymous said...

I don't understand why this continually comes up. With our ship building programs as strapped as they are, and with ships costing as much as they do, are we really going to design and build a diesel boat, something we forgot how to do decades ago? While I think that we should have diesel boats, I don't think we should have them to replace our SSN's but to augment them. To free them up. I think there are some situations close to home (such as training and other...missions) that if we had a few diesel boats would allow more of our SSN's to be forward deployed. Plus you would build up a working knowledge of how to fight a diesel boat which I believe could only enhance our ability to fight them.
Alas, it is not going to happen. The voices of the nukes are too loud for reason...

6/13/2007 5:37 AM

Blogger Unknown said...


I had a post a while back on the subject, and used a little RadCon math to estimate a newcon diesel would indeed run the US a little over half the cost of a VA class.

However, there are other options - such as buying diesels from countries that already make great ones. This would not necessarily be "lowering ourselves to the technology level of our potential adversaries," as the only thing we would be sacrificing would be speed/endurance. We can load them up with our gear, and silencing wise they can be easily on par with us.

But why? As bullnav said, training missions, missions close to home or close to a forward base, etc. This would free up the SSNs to stay forward deployed, train up our ASW forces against a realistic adversary, etc...

Oh, and any author, even Joe Buff, loses me when they start talking about how UUVs & etc. can help level the playing field. UUVs are lumped right with the LCS in my book - unproven powerpoint engineered pipe dream panaceas. If you are counting on technology that does not exist yet to save your butt, you have already lost.

6/13/2007 12:29 PM

Anonymous Anonymous said...

What PBS said about UUVs. Surveil hundreds of miles of coastline with a few UUVs? Give me a break. Get them working and I will believe you. Not there yet. Not even close.
I also agree with buying diesel boats "off the shelf" because then you are not paying the capital start-up costs.
Again, I don't want to replace nukes with diesels. I want defense in depth. I want the right mix to keep us the best in the world.

6/13/2007 8:07 PM

Anonymous Anonymous said...

i believe the fundemental problem with the nuclear subs has nothing to do with size or manuverbility but it is the lack of ability for a nuclear sub to shut down in order to stay silent but a deisel sub can shut down its engines without overheating and killing everyone on board in order to be silent which is the ultimate aim of a submarine

6/07/2008 8:18 AM

Anonymous Anonymous said...

"And personally, I'd rather have one SSN than two AIP diesel boats if I was in a fight -- speed is life."

Not in submarine warfare it's not. Stealth is life. And Diesels are much more stealthy.

7/26/2008 9:01 AM

Anonymous Asaf said...

"lowering ourselves to the technology level of our potential adversaries isn't a smart move"

This kind of hubris will get you nowhere. Calling a technology that was able to thwart USN best ASW operations (see NATO exercises and the Gotland class lease) inferior is just setting yourself for a nasty surprise in the next conflict.
Every nation pride itself with their achievements and technology but this time you'll have to face the facts. Nukes are best for some purposes and 2nd for others.

4/18/2009 3:29 AM

Blogger Unknown said...

Speed is life? No. Speed is noise.

10/15/2009 12:24 AM


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