This question is addressed to current and former submariners…in this era of nuclear submarines, why do the smaller navies of the world still use diesel-electric subs? These submarines are small, and their underwater endurance is limited (by the need to surfac eand recharge the batteries). I realize that they are cheaper to build than nuclear-poweredsubs, but why have them?
Another question: how much of an advantage is it tohave exceptionally deep-diving subs? I understand that US attack subs can go to at least 1500 feet of depth-but is it worthwhile to have this capability? Isn’t a 300-400 ft. depth siufficient? Would an attack sub capable of >12,000 feet be worthwhile? Of course such a sub would have to have a VERY thick hull!
By the way…deep dives must be very dangerous=once you pass a certain depth, isn’tit hard to “blow the ballast”? Suppose you are on a descent, and the power fails-are you doomed?
I do not know of any countries who use diesel subs at all anymore. My father was on a diesel sub in the 50’s and 60’s. They are loud, crude, more of a surface ship that can go under water.
I don’t believe there is any use for diesel subs anymore.
Efficacy of exceptionally deep diving subs: They are quieter, and much harder to track as they can blend in with underwater formations. Though most don’t get that close to the floor of the ocean.
Subs now-a-days can submerge off the Atlantic coast of the US and pop up in the eastern Mediterranian.
IMHO - The nuclear submarine program the United States has is the largest deterent for other nations against formal attack of the United States. They put new meaning to Silent-but-Deadly.
I may be biased as I come from a huge Submariner family.
IIRC, when running on batteries (and not moving), diesel-electric subs are quiter than nuclear ones (nuclear subs still have run the reactor pump or something).
Brian
Any of the small countries with subs are surely diesel-electric, since they definitely aren’t nuclear. Like North/South Korea in particular, although I’m sure there are others.
Diesel-Electric: The electric motor for the diesel electric is indeed quieter than the nuclear reactor. However, all of the DE subs of which I am aware lack the high-tech noise absorbing material, streamlined shape, designed propellers etc. that are on the U.S. Navy nuclear subs. Partly this is due to money issues and partly due to the need to design the sub for surface travel.
Depth: There are thermal layers of water in the ocean. Sound tends to rebound off of the boundary between the layers. It is a lot easier to hear something many miles away in the same layer than something very close by in a different layer. So, if your subs can go down into a layer that nobody else’s subs can go to, you have a tactical advantage.
Not a submariner, but this thread is in dire need of some real facts.
A quick survey of Haze Gray shows the diesel-electric forces of a number of nations, chosen purely for reasons of personal interest:
Iran: 3 Kilo-class (Russian designed) subs. Reported to have serious operational difficulties.
China: 2 “Improved” Kilo-class subs; 2 Kilo-class subs; 1 Song-class, with two more in construction; 17 Ming-class with one more on the way; perhaps as many as 38 operational Romeo-class (Russian designed) patrol subs.
Taiwan: 2 Hai Lung-class (Dutch-designed) boats; 2 ex-USN Guppy IIs patrol subs.
Pakistan: 1 French-built Khalid-class, with two more Pakistani-built versions on the way; 6 smaller French-built coastal submarines; possibly 2 midget submarines.
India: 10 Kilo-class; 4 Russian Foxtrot-class; 4 German Shishumar-class coastal subs with 2 more on order; six French-designed Scorpene-class subs planned to be assembled in India.
It’s my opinion that there has been a wide proliferation of diesel electric boats in recent years, which was also the assertion of an article in Scientific American many years ago. A real waterbug will tell you the inside scoop, but the upshot is that when running on batteries, a diesel-electric is just as quiet as anything out there.
Of those, it is my understanding that the Kilo is one of the most numerous and also one of the most effective. The above-cited article states that they’re capable of detecting enemy subs at three to four times the distance at which it can be detected itself. In confined waters, like the Persian Gulf or the Taiwan straight, these guys could prove to be a royal pain in the ass, because they can recharge their batteries in protected waters.
Oops. I should correct myself. A diesel-electric has the potential to be just as quiet as anything out there. I think the Kilos most closely approach the stealth technology of a nuclear attack sub.
I wonder if the new air-independent propulsion systems being fitted on the Kilos are still based on the peroxide-fueled Walter turbine boats with which the Germans were experimenting at the close of WWII?
Other countries with diesel-electrics: Austrialia, Indoneisa, Japan, North Korea, South Korea, Russia, Singapore, Argentina, Brazil, Canada, Chile, Colombia, Ecuador, Peru, Venezuela, Egypt, Israel, Algeria, South Africa, Bulgaria, Croatia, Denmark, Germany, Greece, Italy, Netherlands, Norway, Poland, Portugal, Romania, Spain, Sweden, Turkey, and Ukraine.
To my understanding, the only countries that have subs but no diesels are the US, UK, and France.
There are plenty of diesel-electrics out there- as a matter of fact, the only countries with nuclear subs are teh US, UK, France, Britain, China and Russia.
Diesel-electrics are actually *** quieter *** when running on batteries because they use the same electric motors that nuclear subs do, but don’t have the reactor cooling systems running constantly(batteries are silent).
The hitch is that they can only run on batteries for a limited time, then they have to snorkel for a while and run the diesels both to get where they’re going and to recharge the batteries. This is pretty noisy, and also opens them up to being spotted by surface ships, since the snorkel sticks out of the water.
From what I can tell, the German Type 207-Type 212 series of subs is the most common out there.
Yo Bump,
I think you need to “get a little time on the pond” before you talk about subs. Nuclear subs use steam turbines, not electric motors for primary propulsion.
One more thing about diesel/electrics, they don’t need to use cooling water when running on battery.
This means there are fewer pumps running, and so they are very much quieter.
The warm outlet water can be tracked too, either by torpedoes looking for thermal differances, or even from satellite where although the sub is not detected, its course can be seen and patrol routes established.
This is very helpful in the listener wars, if you know th elikely patrol routes then you can lay down devices on the sea bed for tracking.
It also helps in estimating levels of deployment.
Its not as easy with deisel electrics, which are also very much cheaper to maintain.
Ralph124c: Naval propulsion reactors sacrifice fuel economy for size. To get decent power and core life (time between expensive, years-long refuelings), you have to use weapons-grade uranium (or possibly plutonium; we don’t but I think the Soviets did in some boats). For countries without nuclear arsenals, the stuff is either to much trouble and political baggage to obtain and secure, or it’s reserved for their WMD programs.
Bump/Richw211: We did build two electric-drive SSN’s, the Tullibee and the Lipscomb (both now long decomissioned).
Casdave: surely a diesel boat running on battery produces some waste heat; do they secure main sea water and just run a smaller aux seawater pump, or secure all seawater and recirculate freshwater that gets steadily warmer?
My boat did a three-day exercise with a Japanese diesel-electric boat in the early 90’s. I forget the make of the boat, but they tied up across the pier from us afterward and the shape of and rubber outer insulation on their hull did not look inferior to ours. I didn’t get a close look at their screw, but I recall Tom Clancy complaining about Toshiba selling the Soviets a state-of-the-art propeller milling machine in the late 80’s, so I assume the same technology was avilable to them. And since all our nuclear submarines have to be able to run on the surface too, I don’t see why they couldn’t use the same screws as us.
The rules of the exercise required their boat to snorkel every four hours or so, though at low speeds a full battery charge would last at least a full day. My understanding was that otherwise we would never have been able to aquire them, and that if a diesel boat with a decent charge happens to be right in an SSN’s path, the first thing that SSN hears is going to be torpedo tube doors opening just prior to launch.
I was in the engineering department so I can’t quantify “right in an SSN’s path”. My vague impression is that even the Persian Gulf is still many times wider than a diesel boat’s practical intercept radius.
Thanks for the info…but again my question: suppose you descend to a depth so great that the outside water pressure is greater than the air pressure in your ballast tanks…then you can’t discharge your ballast water (“blow ballast”). So, under these conditions (and if you lose power) you will just continue to sink until the hullimplodes! I believe this happened to a Soviet sub once…surely the last few minutes for that crew must have been the worst time imaginable.
Anyway, I have huge respect for the submarine guys…I could never do that!
You also have to look at the use for the submarines. Not too many countries need open water navies - many of them keep quiet, short ranged diesel electric subs as coast defense ships against foreign blue water navies. Chinese nuclear subs, for example, in a Taiwanese conflict, would prove to be a big pain in the ass for US forces to keep track of. They can move to position ahead of time and potentially ambush the fleet, being nearly undetectable when running on electrical motors.
As far as the ballast things, I’d imagine that air is compressed to such a degree that the hull crush depth comes into play before you become unable to blow the ballast tanks, though I’m not sure.
Regarding why anyone would bother with Diesels, in addition to all that’s been said here about the advantages of one over the nuclear subs favored in America; Even if diesel-electrics weren’t comparable to nuclear subs, only a small handful of countries have nuclear subs. Performance vs. nuclear subs only matters if you plan on tangling with one of those few countries. Look at the dismal performance of the main battle tanks in service in much of the world compared to the Abrams tank in use by America. But it doesn’t matter in the slightest unless, of course, you plan to fight America. If you just want to beat up on your neighbor, Backwardistan, it’s good enough.
Yeah… I botched this one. But… either way, good d-e subs are quieter on batteries than nuclear subs.
And… it looks like the later boats of the Virginia class will be nuclear/electric, as well as the Zumwalt class of destroyers.
That’s an interesting cite, bump. It seems to indicate that SSNs and D-Es are actually reaching the same technological conclusion from opposite sides of the problem: a common electrical bus for propulsion and systems combined with an air-independent power system, nuclear or otherwise.
With the introduction of AIPs in the traditional diesel-electric boat, it looks to me like non-nuclear solutions have the potential to partially close the gap in stealth, range and performance in the near future.
I know the diesel boats are quiet, but couldn’t an active sonar bouy detect them just fine in that hypothetical Taiwanese conflict?
Canada just purchased 4 diesel subs from the British. The navy web site is here.
Yes, that active sonar bouy could detect it just fine, if you know where to look. If you just use active sonar indiscriminantly, you’re never likely to find anything, as your enemies can hear the sonar at a much greater distance than you’ll get a return off of the sub.
Back to the SSK vs SSN debate - don’t modern US SSN’s use natural convection currents instead of pumps for their cooling systems? I seem to recall reading that in some Tom Clancy novel sometime(I think it was The Sum of All Fears).