Pardon my posting, but I have a (relatively) simple naval/military question this week, with two parts…The begin with, after ballistic missile submarines launch their missiles, what ends up in the empty missile tubes? Would they pump out the seawater that would rush in? And second…in the event of nuclear war, after launching their missiles, what are the missile boats supposed to do next? Return to port?
Well, thanks for your patience,
Ranchoth
Well, after launch, the primary order of business would be to evade the enemy naval forces that will shortly converge on your position, and get back to friendly waters as quickly as possible. Boomers are probably too expensive to lose at sea.
And I believe they evacuate the tubes with compressed air, same as a torpedo tube.
Of course, I’m not navy, so my answer isn’t authoritative.
I doubt you’re going to get an answer to your question.
IIRC, the missile tubes are filled with seawater to equalize the loss of payload ballast, (i.e. you just lost several tons of ballast - add seawater to the cavity to at least simulate what was lost).
I read this somewhere, and saw it reverified somewhere else. I’ll drop a cite as soon as I can find where I read it.
Tripler
I think I remember where. . .
Ballast didn’t even occur to me. Which, I suppose, is why I don’t build subs for a living. 
The tubes are partially flooded, for ballast.
The boats would try for a safe harbor. In general, an FBM Boat without missiles is a large and expensive (and very quiet) attack boat, and can do most of the things the smaller and cheaper attack boats acn do, but after a nuclear war… what’s the point…?
So, they return to the nearest safe harbor they can fight their way to, prefferably a surviving American harbor with refit facilities.
Just wondering…Do these ballistic missile submarines have any serious armament (or any armament at all) beside the missiles? Would they be of any use after having launched the missiles? Or could they be used for anything else than launching missiles?
OK…Tranquilis has already answered my question. Next time, I’ll read more attentively before posting…
They have torpedos. Depending upon who the enemy of the day is, this alone makes them pretty lethal. So, even if they’ve shot their wad of missiles, they can still serve as an anti-surface and anti-sub platform.
Comrade, is this a good idea?
Da, da, is Tranquilis idea.
I don’t think military planners really thought about what happened next. After full-scale nuclear war, who cares about a few dozen subs?
Kinda hard to think of the next step after the end of the world as we know (even if you do feel somewhat okay).
Well you try to do what seaquest does and get transported to an alien world that may actually have a viable atmosphere that isnt contaminated with radiation.
You mean have an awful third season and get cancelled?
This is ridiculous. Our planning does not stop once the missile silos are empty.
And to back flyboy88 up, there is a survival plan for those in the LCCs (who actually turn the key on silo-based ICBMs).
Tripler
It’s not a happy one, but it does exist.
[interservive dig]Yeah, they are still in the Air Force.[/interservice dig]
[sub]You know I love ya![/sub]
Officlially:
[sub]I never said it was a happy thing[/sub]
Unofficially:
[sub]Hey, it could be worse. . .[/sub]
Tripler
Yeah, I’ll see you in Bartertown. 
Yes, each crew member squats, places head firmly between legs and kisses his ass goodbye. Each “boomer” contains roughly 160 megatons (US boomers) of bombs. There are 18 capable of patrol at any time. Soviets had similar numbers with bigger bombs. Evenly spread over the northern hemisphere, this will cause Hiroshima times 30 style events at a few thousand locations with city limits style Chernobyl type fallout all over the world. That doesn’t account for silo missiles and bomber missiles. When it’s over because of an exchange of missiles, it’s over.
I’m sure they could find a friendly port that didn’t get nuked. How many nukes are targeted at the southern hemisphere? New Zealand might make a nice stop.