...then they should have crept up to depth by slowly pushing out ballast, as they can do now...
...You don't even have to make noise with the prop.
Most of the noise of changing depth has to do with increasing/decreasing outside seawater pressure on the hull and it's expanding and contracting under that pressure. "Hull popping"
My comments about the prop has to do with cavitation and why they remained deep where you won't cavitate. Not anything to do with the act of changing depth itself.
Changing depth can be accomplished by two methods.
You advocated for one method (using the ballast tanks) over the second method( Using the dive planes and propulsion).
Both tactically and feasibly, you are completely 100% wrong.
Using the propulsion is the preferred method.
ALWAYS.
The Main Ballast tanks are ONLY for surfacing and submerging. Never for altering a submerged depth. For that, there is a separate trim system for altering the buoyancy of the sub. And THAT is used to MAINTAIN NEUTRAL BUOYANCY, not to make radical alterations to buoyancy to effect depth changes.
Maintaining neutral buoyancy is a balancing act, one that gives an ever increasing probability of something going wrong the more you screw with it. Better to make small changes to KEEP a neutral buoyancy, than it is to make alteration to cause the sub to be heavier/Lighter, and then make a second alteration to return it to neutral. You are just asking for trouble.
Also.. Flooding and blowing those tanks Are a
much greater radiated noise level than the screws making slow revolutions and the plant on low power..
Also, it takes compressed air to blow those tanks and if you constantly use that method to alter depth, you are going to run out of that finite supply of compressed air and the only source of replenishment is out of reach at the surface.
So not only is it tactically unsound, it is foolish and dangerous as well.
I joined the Navy to see the world, only to discover the world is 2/3 water!
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Blueghost
11 years ago
I've been told by Janes that you can creep up without excessive noise from the ballast system. I don't know, since I'm not a submariner, but everything I've read about modern subs suggests that this is doable without all the extra gushing that used to be associated with the exercise. My guess is that the engineering is to pump out the water while gradually letting in with to make up for the pressure difference. That as opposed to forcing air into the ballast tanks to literally blow out the water, which is not what I was suggesting.
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CGSailor
11 years ago
My guess is that the engineering is to pump out the water while gradually letting in with to make up for the pressure difference. That as opposed to forcing air into the ballast tanks to literally blow out the water, which is not what I was suggesting.
The trim system is pumped, not blown this is true.
Regardless of whether the tanks are pumped, blown, or flooded... The tanks must be vented. Otherwise if you were pumping water out of a tank, you'd be pulling a vacuum. Air compresses. Water does not(to any appreciable degree). This means the deeper you go and under greater pressure, the MORE AIR is needed to displace a like amount of water by volume.
So even slowly pumping the tanks requires a source of air. They can vent to the boat itself, but then you'd be pulling a vacuum on the ships crew when you try to pump water out of the tanks.
Can subs creep up silently?
Yes. I was not disputing that. Only your method for doing so was not sound. Not in comparison to the method which you dismissed erroneously.
Regardless, your original assumption concerning the premise of the movie is correct, though not for the reasons stated.
The whole story IS shaky.
But not because they could have slipped up silently to launch depth to confirm a questionable message.
But because of the very procedures of the messages themselves. The entire process is Fictionalized Hollywood, but necessarily so. The real procedures being highly classified. The very notion of an "abort message" Questionable or not, cut off or not, unconfirmed or not...is complete BS.
The Launch Authorization is NEVER given unless it is 100% sure you are not going to change your mind under ANY circumstances. There is no "abort" protocol once the launch order is confirmed.
But it is necessary for the sake of the fictional story. so...
I joined the Navy to see the world, only to discover the world is 2/3 water!
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Blueghost
11 years ago
Yeah, that was my feeling on it. I saw a doc on boomers in the mid 90s, and from what I recall once you get the order, you confirm it on the sub. Once you do that you let the birds fly. No ifs ands or buts, as you say.
If I had made a sub film, it would have been different. The crew would not have been at odds with one another.
The dirty little secret about Hollywood is that a lot of the heads of studios see themselves as a social compass for America, so when they make a "war film" it is rarely against another country. That's why here we didn't see the crew of the Soviet film. The idea is that war against another nation state is a bad thing regardless of the circumstances, unless it's a WW2 film about fighting the Nazis. Largely because there's a strong Jewish tradition in the American film industry; therefore you have a lots of reminders about the horrors of the nazi regime so that the public doesn't forget. That's not bad in and of itself, but, coupled with that, as I say, is the notion that any kind of organized conflict, regardless of circumstances, should not be considered.
Is that a bad thing? Well, I can't see it as being a good thing. The reason is because then you have to really reach to make a military action/thriller in terms of story, so as to make it nearly implausible as per the mutiny that occurred on the Ohio class in this film. Note that they filmed on a French carrier and not on American carrier during the "NEWS" segments. The Navy was probably reluctant to help given the nature of the story.
There's tons of good sub movies waiting to be made, but if it involves the US beating up on some country, then you'll never see it as per the previous stated reasons. Something like "The Hunt for Red October" was a fluke because it involved a rogue Captain trying to bring himself, the sub and crew to "freedom", so something like that is okay.
But, for instance, say a 688i going after a North Korean sub, or a Russian or Ukrainian sub? You'll never see it on the big screen. Ever wonder why Battleship was made about a BB going after aliens instead of bombarding the coasts of someplace like Somalia, Iran or Iraq? Same thinking. Remember "Aliens"? The colonial marines fights hyper aggressive animals that are pure evil as opposed to another nation holding hostages.
All of that applies to the Submarine and military genre as a whole. It's a sad state of affairs, particularly since the next big war will be with drug cartels in central America, and possible with China.
Oh well.
Thanks for the exchange.
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CGSailor
11 years ago
Thanks for the exchange.
I joined the Navy to see the world, only to discover the world is 2/3 water!
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Blueghost
11 years ago
Just one more thing, just so I don't sound like a raving anti-Semite, because I'm not, I love films with Nazis as bad guys and half my friends growing up were Jewish, and I don't give a flying-F if all of Hollywood is Jewish, it's just the simple fact that I am sick and goddamn tired of seeing Nazis in everything as the ultimate bad guys.
Hopefully movies in the future won't forget about the evils of Nazis, but also, it would be nice to examine the evils of Stalinist Russia, South Africa during apartheid, Poland under Soviet domination during the Cold War, and currently, like I said, the just pure evil stuff that drug cartels carry out against people in Central and South America.
I'm going to make a submarine movie, and it's going to rock. And it'll be about a US sub going after a commie Sub.
Enough said.
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