Yea, we are probably splitting hairs. What I am getting at is that, according to my guy, the diesel sub can turn off it’s engines, sit on the bottom of the ocean and look like nothing other than a rock amid a million rocks. The nuclear sub can attempt the same thing but due to the fact that the reactor is still operating, there is a signature. One can be located, the other can’t other than mapping its last location. I don’t know what the radius is for a diesel sub operating on batteries is but it is capable of moving from the spot where is was last identified. See what I mean? Then it can sit and wait. Of course, when the diesel engines reactivate it is readily detectible but the game of cat and mouse can get very interesting.
Layman ansewer would be yes, the nuke boats would have pumps that can be heard, in the movie the hunt for red october, you have that one scene where Jonesy is breaking down that audio tape and you can hear the thrumming of the pumps.
In submerged mode, the diesel electrics are just electric motors. The only problem with them, is that they are like a bucket, go faster and you empty the bucket that much faster , so they have to practice conservation of energy
Lurking around at station keeping speed, would increase their time on station relative to the amount of supplies that they would have, where as moving at flank speed may reduce the batteries to hours worth of usable energy.
Too many people are calling them mobile mine fields now anyways. Their silence is golden if they get to fire the first shot and after that the detection radius is really small.
Declan
Modern sub warfare is not anything like WWII sub warfare.
No one puts their sub on the bottom and makes like a rock anymore. I suppose it could happen but it is very unlikely.
The US sub fleet is a blue water (i.e. deep water) fleet. The ocean floor is waaaaay below where they can go. We have two types of sub…boomers and fast attack subs. Boomers strictly stay in deep, deep water. They have no need of getting in coastal waters. Fast Attack subs may go anywhere but usually they stay in deep water too. Even when they do go in shallow waters (to insert SEALS or do land attack missions) they are not there for long. They do their thing and scoot and they are quite fast…fast enough many surface ships would have trouble closing on them.
Also note in modern warfare a sub almost certainly knows what is remotely near them on the surface. They will not disclose their position by firing (or whatever) if they have reason to believe there is a surface ship close enough to cause them trouble. In WWII they could not know these things. Modern subs also have vastly superior torpedoes with brains of their own not to mention Tomahawk missiles such that they can shoot accurately from far greater range than a WWII sub.
A diesel sub I think is quieter but as mentioned this is splitting hairs. You are almost certainly not going to know the sub is there till it shoots at you and unless you have assets very near the sub when it shoots it’ll be long gone by the time you get there to shoot back. Helicopters/planes are your best bet.
And, in the end, the ability of a nuke to not have to surface to recharge batteries is a greater advantage than the diesel being somewhat quieter. Modern diesel subs are a far cry from WWII subs but in the end their advantage is time limited and then they are vulnerable. The slightly noisier nuke has advantages that more than make up for it.
FWIW in that movie the noise he hears is the unique sound of the Caterpillar Drive. That propulsion system was, in the movie, supposed to make the Red October undetectable but Jonesy (and an Alpha captain) manage to isolate the unique sound the sub makes using that drive and could program a computer to pick out that particular sound (remember in the movie the computer identified it as a geological anomaly…or something because it was originally programmed to look for geological events). Unless you knew what to look for the sub was uber-stealthy which made it scary.
Pumps had no part in it.
Not counter-intuitive at all, since they can run on batteries. That’s the main advantage of diesel subs, in fact.
For this reason, they’re more useful than nuclear subs for coastal defense, since they can be almost perfectly silent and come back to a safe heaven when their batteries run low (rather than keep sailing using thier diesel engine). Could be useful for an escort, too, since the ships they’ll be following will be detectable anyway, and they can switch to batteries when needed for action.
FTR, all French attack submarines (as opposed to ICBM-launching subs) run on diesel. The general idea being that they would switch to batteries when reaching the zone of operation.
Somewhat of a change of direction here. I recall at one point hearing that we could track Soviet submarines from their wake given a known starting point and direction. Was that just Cold War hype, or were we capable of interpreting the effect on the surface of a sub traveling deep under water?
Modern Stirling AIP engines give non-nukes the ability to run at depth for as much as a few weeks, in fact.
Never heard of that (which frankly means nothing…I am no expert).
IIRC there was a time during the Cold War where the US was excellent at tracking Soviet Subs. There is a story, do not know if it is true, that the US had all their subs following Soviet subs ping them (an unmistakable sign someone is right on top of you). They did this simultaneously. It was a message writ large to the Soviets that when it came to subs we had their number.
A Stirling engine sub?
The issue is being quiet. Electric engines run off batteries are quiet. But batteries need recharging so you run the significantly noisier diesel engines to do that. Is a Stirling engine somehow silent?
Nukes are noisier than a ship on batteries but quieter than a ship running diesel.
As with most things your choice is a tradeoff. You have to decide the role for the ship and make the best compromises you can.
The noise from the nuke depends a great deal on the speed of the sub. In most modern subs there is a mode where the coolant is circulated via convection rather than being pumped. This eliminates the noise from the pumps, allowing the sub’s sonic signature to be very, very small.
The French seem to have a number of nuclear attack submarines of the Rubis class - do you mean that they run them without the reactor or ?
I honestly don’t have any idea of how much noise a Stirling AIP engine makes submerged, and I’m guessing that whoever could tell me would probably have to kill me afterwards.
As you say, I’m guessing that even they’ll run off batteries while being actively hunted. The air independent propulsion system does on the other hand allow the sub to stay submerged and load their batteries at depth, which I think lowers the chance of getting caught by patrol craft.
I can not believe that is true. If we had their number, we wouldn’t want them to know that we did.
I could believe that perhaps someone determined we could do that, and the story got stretched a bit.
Technically, yes, but that would never, ever happen. A nuke boat is not designed for serious maneuvers on electric power, and I highly, highly doubt it would be seriously combat capable (yes, it could launch torpedoes and such, but not maneuver at all) without the reactor running.
You’re 100% right on the boomers; they aren’t there to do anything but be a deterrent.
688(I)s or Seawolfs, however, could definitely be used in shallower waters depending on what COMSUBPAC/LANT wants them to do. Tomahawks don’t have unlimited range, and they may have to venture into shallow waters to launch; they may also be assigned to interdict surface ships or subs, or blockade a port. Shallow waters ops are definitely plausible for attack subs.
If they were in shallow waters, they likely wouldn’t scoot as soon as they engaged, anyway- as quiet as our subs are, at flank speed, nothing comes close to silent, and they could be picked up for miles away. Our Silent Service’s typical modus operandi is just that-silent in, silent out.
Regardless of all that, you don’t necessarily have to literally be on the seafloor so be silent- the main advantage of diesel/electric subs over nukes is that when running silent and at a full stop, diesels are pretty much completely silent- the only sound coming out of them will be the crew dropping wrenches and shit like that. (Depending, of course on the sub- there are a million things that could make noise, but the crew usually gets on that when rigged for silent running). In the same circumstances, a nuke does have to run its coolant pumps or overheat the reactor and have bad things happen.
I’m a former submarine officer myself.
I don’t disagree with anything you’ve said here in your second post.
I don’t disagree with anything here, either.
To both of the previous posters: I said nothing about whether or not a nuclear sub would shut down its reactor in a tactical or operational situation. I was simply responding to Mr. McMurphy’s initial statement that “In real life, a sub’s nuclear reactor cannot be shut down.”
First off, the statement is nonsensical in and of itself. Of course a submarine’s nuclear reactor can be shut down. Even I grant that you meant that a sub’s reactor cannot be shut down while operating at sea, it’s still wrong. As I stated, the reactor on operating submarines is shut down all the time for drills. I should know, considering that I’ve conducted fast recovery startups at sea more times than I can remember.
There appears to be something to this. But it could still just be something we want others to believe.
Nope, I doubt the part about pinging them, but the USN was trailing soviet boats the minute they left port, their boomers anyways. Then a guy named Walker told the soviets that it was happening and made the soviets a bit paranoid, enough that a maneuver called a crazy ivan was invented.
Since subs are blind in the baffles , unless they have a special acoustic sensor trailing out the rear, would abruptly turn ninety degrees to either port or starboard. Very irratating to anyone who happened to be tailgating at the time.
Declan
This sounds like a sub version of the Fake bomb on the decoy airfield story. What would be the point of letting the Soviets know we could trail them?
By all means, I cede to your expertise then.
Just out of curiosity, what classes of subs did you serve on? About how long would it take to restart a reactor? I have trouble thinking of a situation where the reactor would have to be shut down yet would not cause enough permanent damage to allow it to be restarted.
robby, Thank you for your service. I’m jealous. I always thought that if I had joined the armed forces, it would be the Navy, and Submarines would be my preference.