Columbia-class SSBN (SSBN-X Future Follow-on Submarine)

sdmuleman said:
TRF-B (and presumably KB) are 751 ft. SSBN is 560 ft. The docks could certainly physically fit a longer boat, problem becomes the amount of additional space needed for things like shaft replacement. I suspect one could go up to 600 ft or so without significant impact, though it might limit ability to do a shaft and removing the bow dome at the same time (not that removing the dome is overly common).
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Yeah, I didn't want to get too deep in the weeds on needing drydock length to replace shafts etc.

I don't remember seeing a dome removal, or even hearing about one getting done, but I was only in for 5.5 years and my friend working for IMF after he retired doesn't talk shop except in person.

So I think we can safely make that particular event an either-or for drydock length limits. Or one nightmare mid-refit refloat&reposition (*shudder*).

Each quadpack adds ~30ft, so adding one quadpack would make the ship length ~590ft. Adding two quadpacks would put you up to ~620.

But that gets us back to the ballast tank size problem. Would a Columbia+2 be able to submerge without redesigning the ballast tanks?


sdmuleman said:
Fully understand maintenance done during refits. However, Ohio plan has that and the multiple year refueling. Columbia presumably does the same refit schedule, but without the refueling, which means either there's less major maintenance needed, or even more work is going to need to get done in refits. Probably some of both.
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I expect it to end up more work-hours in refits. While individual systems will likely require less maintenance, not having that midlife refit time will cause all that work to happen across a dozen or so standard patrol refits at the ~20-30 year mark.

The whole TRIPER planned-replacement-before-expected-failure program is going to need a whole new look!
 
whatismoo said:
I did the math a bit back and we need something like 24-36 boats to equal the Ohios. (24 for the current 14x20, 27 for 18x24, and 36 for the planned 24x24 Ohios).
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I get 18 to get an equivalent number of tubes as 14x20 OHIOs. Or probably 15, once you allow for two OHIO out of service for major work that COLUMBIA (allegedly) doesn't require.

But worth bearing in mind that when the OHIOs replaced the Polaris/Poseidon boats, they went from 41x16 down to a (planned) 24x24, rather than the 27x24 that would be needed to maintain tube count.
Scott Kenny said:
Or one nightmare mid-refit refloat&reposition (*shudder*).
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Not that much of a nightmare. The nuclear lot get a bit squirrelly about the condition of the boat at each docking evolution, but refloat and reposition is a standard operation at any competent dockyard.
Scott Kenny said:
Would a Columbia+2 be able to submerge without redesigning the ballast tanks?
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Sure, if you design the hull plug to be neutrally buoyant. The question is, will there be adequate reserve buoyancy once you've done that? Depending on the pressure hull and MBT arrangement, you might be able to add plugs to the fore and aft MBTs at the same time without screwing things up too badly. But it'd be expensive to do that redesign.
Scott Kenny said:
While individual systems will likely require less maintenance, not having that midlife refit time will cause all that work to happen across a dozen or so standard patrol refits at the ~20-30 year mark.
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The problem comes if something big fails that needs holes cut in the pressure hull. If you have planned refuelling intervals, it only screws up the programme until the next major docking. If you plan never to need to cut the hull open, it screws up the programme for the life of the entire fleet.

And that's assuming that nobody took advantage of 'we'll never need to open the hull' to put something large and expensive in the way of whatever wound up breaking. Which, on a submarine, they will have done. They're tight enough for space without adding more design constraints.
 
Yellow Palace said:
I get 18 to get an equivalent number of tubes as 14x20 OHIOs. Or probably 15, once you allow for two OHIO out of service for major work that COLUMBIA (allegedly) doesn't require.

But worth bearing in mind that when the OHIOs replaced the Polaris/Poseidon boats, they went from 41x16 down to a (planned) 24x24, rather than the 27x24 that would be needed to maintain tube count.

Not that much of a nightmare. The nuclear lot get a bit squirrelly about the condition of the boat at each docking evolution, but refloat and reposition is a standard operation at any competent dockyard.

Sure, if you design the hull plug to be neutrally buoyant. The question is, will there be adequate reserve buoyancy once you've done that? Depending on the pressure hull and MBT arrangement, you might be able to add plugs to the fore and aft MBTs at the same time without screwing things up too badly. But it'd be expensive to do that redesign.

The problem comes if something big fails that needs holes cut in the pressure hull. If you have planned refuelling intervals, it only screws up the programme until the next major docking. If you plan never to need to cut the hull open, it screws up the programme for the life of the entire fleet.

And that's assuming that nobody took advantage of 'we'll never need to open the hull' to put something large and expensive in the way of whatever wound up breaking. Which, on a submarine, they will have done. They're tight enough for space without adding more design constraints.
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I may have made a math error, that's a mea culpa. I had notes on this somewhere but couldn't find them.

Polaris/Poseidon->Trident was a (partial) upload, so while missile counts decreased somewhat, I am pretty sure warhead count went up. Range and accuracy certainly did.

41 For Freedom (A3/C3)

12x 16 C3 @ 10-14 * 40kt MIRV / ±560m @ 4600-5900km
29x 16 A3 @3 * 200kt MRV / 900m @ 4600km
1920+1392 = 3312 warheads
76.8mt +278.4mt = 355.2 megatons

Vs
Ohio (C4/D5)
8x 24 C4 @ 8 * 100kt MIRV / 250-300m @ 7400km
16 x 24 D5 @ 8-12 * 100kt MIRV / 100m @ > 12000km
1536+4608 = 6144 warheads / 614 megatons

Now we only made allegedly around 3400 W76, but there's also W88 and I don't want to make the math hard on myself.

The point of this exercise is that while the 41 For Freedom to Ohio transition did result in a reduction in boats and tubes, it led to a (planned) increase in yield, range, throw weight, and warhead count. Ohio to Columbia doesn't do this, at least not unless we can fit like double the W93 per D5LE vs W76. And given that these decisions were made at the height of 2000s-2010s anti-strategic decision making, I'm not optimistic about things.
 
Yellow Palace said:
I get 18 to get an equivalent number of tubes as 14x20 OHIOs.
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Except we had 18x24 Ohios, of a planned 24x24 (thanks "Peace Dividend"). We only dropped to 14x20 to be in compliance with a now defunct treaty. It could be argued that we need the equivalent of 24 Ohios (or more, given China wasn't the threat then as it is now). That's 24^2/16 = 36. Minimum.
 
Sferrin said:
Except we had 18x24 Ohios, of a planned 24x24 (thanks "Peace Dividend"). We only dropped to 14x20 to be in compliance with a now defunct treaty. It could be argued that we need the equivalent of 24 Ohios (or more, given China wasn't the threat then as it is now). That's 24^2/16 = 36. Minimum.
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I think "36 for Liberty" has a nice ring to it tbqh
 
Yellow Palace said:
Not that much of a nightmare. The nuclear lot get a bit squirrelly about the condition of the boat at each docking evolution, but refloat and reposition is a standard operation at any competent dockyard.
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It's not the refloat-and-reposition action that is the issue, it's the having to stop work for however-many hours/days while it's happening that is the issue.



Yellow Palace said:
Sure, if you design the hull plug to be neutrally buoyant. The question is, will there be adequate reserve buoyancy once you've done that? Depending on the pressure hull and MBT arrangement, you might be able to add plugs to the fore and aft MBTs at the same time without screwing things up too badly. But it'd be expensive to do that redesign.
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Exactly. Painfully expensive.

Which is why it's more likely to make more hulls than to stretch them.
 
Scott Kenny said:
It's not the refloat-and-reposition action that is the issue, it's the having to stop work for however-many hours/days while it's happening that is the issue.
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Which comes back to how often you're doing it: if it's a once-a-patrol task, that's unreasonable. If it's a once-in-five-years job, then don't worry about it. You need to alternate docking positions anyway to make sure you get access to the entire hull for coating maintenance.
 
Sferrin said:
Except we had 18x24 Ohios, of a planned 24x24 (thanks "Peace Dividend"). We only dropped to 14x20 to be in compliance with a now defunct treaty. It could be argued that we need the equivalent of 24 Ohios (or more, given China wasn't the threat then as it is now). That's 24^2/16 = 36. Minimum.
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Regardless of the reasons why you reduced the force, you currently have 280 tubes in the fleet, and somewhat fewer in active service. Increasing that – whether to 336, 432, 576, 676, or some other number – isn't a decision to be made lightly, and shouldn't be done on the basis of vibes or a catchy slogan.

I happen to agree that 12x16, or even 15x16, is likely inadequate for the current strategic situation. But whatever the proper number is, it ought to be arrived at based on considerations of the target system required to achieve the desired deterrent effect, the survivability of the force, and force generation considerations.
 
Yellow Palace said:
Regardless of the reasons why you reduced the force, you currently have 280 tubes in the fleet, and somewhat fewer in active service. Increasing that – whether to 336, 432, 576, 676, or some other number – isn't a decision to be made lightly, and shouldn't be done on the basis of vibes or a catchy slogan.
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No, it should be done based on reality. And the reality was we were getting something for that reduction, and the nuclear threat was less. That changed (and it's not a catchy slogan).
 
Sferrin said:
No, it should be done based on reality.
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Sure. And what is the reality, in terms of increase to the target set and/or the risk to the platforms? Because that may not justify 36 boats. It may equally well justify more than 36 boats. An argument could be made for all sorts of numbers.

But also resources are finite, especially if you're expanding the fleet. Just counting reactors (and therefore reactor operators) - would you rather have 10 CVNs and 36 SSBNs, or 16 CVNs and 24 SSBNs? What if we put nukes on those CVNs? That isn't an easy move either, but could actually mean more deployed weapons.
 
Yellow Palace said:
Which comes back to how often you're doing it: if it's a once-a-patrol task, that's unreasonable. If it's a once-in-five-years job, then don't worry about it. You need to alternate docking positions anyway to make sure you get access to the entire hull for coating maintenance.
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It still puts a multiple-day crimp in the work getting done, and when you're talking some 10k work-hours per day that's kinda a big crimp in getting things done.

I don't actually remember refloating the boats to shift blocks around any time we were in drydock for a refit. And when I first arrived to Georgia she was in dock for an unscheduled shaft replacement! I think I still have one of the crew pictures from when Georgia was down in the drydock. Somewhere!


Yellow Palace said:
Sure. And what is the reality, in terms of increase to the target set and/or the risk to the platforms? Because that may not justify 36 boats. It may equally well justify more than 36 boats. An argument could be made for all sorts of numbers.

But also resources are finite, especially if you're expanding the fleet. Just counting reactors (and therefore reactor operators) - would you rather have 10 CVNs and 36 SSBNs, or 16 CVNs and 24 SSBNs? What if we put nukes on those CVNs? That isn't an easy move either, but could actually mean more deployed weapons.
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12x16x8=1536 weapons deployed. Well, actually that should be 8-or-9x16x8, 1024-1152 additional weapons deployed (SSBN optempo ends up between 2/3 and 3/4 of all subs in service deployed at one time).
Whereas 16 CVNs means +2 deployed, 5 total. You'd need to load some 200 nukes onto each carrier just to have the same number of warheads available. And even then, carriers aren't able to reach the same targets as Trident missiles.

Now, in terms of sheer general utility outside throwing nukes around, I'd much rather have 16x carriers than 10. In the words of Bill Clinton, "when the President gets woken up at 0230, the first words out of his mouth are "where are the carriers?""

I'm not sure it's possible for NNNS to build carriers fast enough to increase the number of hulls in the water. They'd need to increase production rates to something like 1 carrier every 4 years. Cutting the current construction time more or less in half from ~7 years from keel laid to commissioned.
 
A lot of the missiles on todays ballistic subs aren't carrying a full load of warheads anyway as its overkill, instead they have a reduced number of warheads in each missile to about a third and even some missiles carrying only decoys. Several navies have done the maths and decided that with improvements in missile accuracy, the weight reduction and miniaturisation of the new generation of re-entry vehicles, and improved counter-measure evasion that they require less missiles in their subs to generate the same destructive potential.
 
whatismoo said:
Wellerstein doesn't (IIRC) model the interactions of multiple shocks, which tend to strengthen blast effects.
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Without knowing the timing, separation, etc. it amounts to hand-waving.
 
Yes, can folks please keep on topic instead of bringing up tangential stuff. I noticed the same with the SSN(X) thread, wandering off into all kinds of musings that have nothing to do specifically with the topic at hand. Nuclear warhead yields are not completely relevant to this topic, which is to discuss the SSN(X) program - i.e. the submarine. Missile discussion should be elsewhere, like the Secret Missile, Bomb and Gun Projects section.
 
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WASHINGTON — Congressional Republican leaders today put forward a stopgap funding bill to keep money flowing to the federal government through Nov. 21, but notably left out the White House’s request for an extra $3.9 billion for Columbia-class submarines.
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The White House had advocated for the addition of $3.9 billion for the Columbia class submarine in a list of “anomalies” sent to Capitol Hill, Inside Defense reported last week, but the CR does not include that funding.
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https://breakingdefense.com/2025/09...cr-extending-pentagon-funding-until-november/
 
Ye Gods. Why does the workmanship on today's subs in the US look like complete dog $hit?
 
tychosis said:
You are aware this isn't finished, right?
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Wait. You mean that's not a complete SSBN? Looking at that sail. Now look at this Virginia sail right off the showroom floor and compare it to this Ohio that's been in service for 20 years. Terrible.
 

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Sferrin said:
Wait. You mean that's not a complete SSBN? Looking at that sail. Now look at this Virginia sail right off the showroom floor and compare it to this Ohio that's been in service for 20 years. Terrible.
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I'm not entirely certain I see what you're complaining about. There's nothing wrong with either of those sails. What do you see in either of these images that is "terrible" in any operationally relevant sense?
 
tychosis said:
I'm not entirely certain I see what you're complaining about. There's nothing wrong with either of those sails. What do you see in either of these images that is "terrible" in any operationally relevant sense?
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Build quality. Surface finish. I don't expect a class A surface but these things are supposed to be quiet underwater. Maybe they're quiet enough and my expectations are too high. Just seems like we've slipped. That 20 year old Ohio sail looks better than a brand new Virginia.
 
Sferrin said:
Build quality. Surface finish. I don't expect a class A surface but these things are supposed to be quiet underwater. Maybe they're quiet enough and my expectations are too high. Just seems like we've slipped. That 20 year old Ohio sail looks better than a brand new Virginia.
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It's missing every bit of surface treatment, which will be applied after the hull sections are combined.

Here's SSN-704 under construction (c.1980), complete with prominent welding beads between the hull sections
 

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Sferrin said:
Wait. You mean that's not a complete SSBN? Looking at that sail. Now look at this Virginia sail right off the showroom floor and compare it to this Ohio that's been in service for 20 years. Terrible.
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Huh? The Virginia has an anechoic (rubber) coating applied, the slightly uneven surface of which you are misinterpreting as poor (metal) workmanship. The Ohio has no anechoic coating, just painted steel.
 
Wait a minute. You meant that is NOT the new stealth paint/coating?
 
Vepr157 said:
The Ohio has no anechoic coating, just painted steel.
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Wow, the Ohio Class relies purely on other means to reduce noise and detectability to sonar? I always thought it also used anechoic tiles/coating. What was the first USN sub to introduce the tech?
 
EmoBirb said:
Wow, the Ohio Class relies purely on other means to reduce noise and detectability to sonar? I always thought it also used anechoic tiles/coating. What was the first USN sub to introduce the tech?
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At least some of the -688s have them.
 

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EmoBirb said:
Wow, the Ohio Class relies purely on other means to reduce noise and detectability to sonar? I always thought it also used anechoic tiles/coating. What was the first USN sub to introduce the tech?
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Quieting was all internal, tiles were real bad for a long time (Sov boats had them and were still loud as shit for decades), plus they fell off too easily. The USM and RN both put tiles on test boats in 1980, the T-boats and 688i class were the first to hit the water with tiles from the start. Some of the best tiles out there today are arguably the RAN tiles from their SSKs.

The 774s introduced a new coating which is applied as a coating (mold-in-place) rather than broken into tiles, but adhesion problems have plagued the class. Tiles also have this problem, missing tiles are pretty common after a deployment. The 826s will use the most updated version available, it's not immune to peeling but has gotten a lot better lately. The coating always looks "uneven" compared to painted steel or tiles.
 
EmoBirb said:
Wow, the Ohio Class relies purely on other means to reduce noise and detectability to sonar? I always thought it also used anechoic tiles/coating. What was the first USN sub to introduce the tech?
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The first submarines to introduce anechoic coatings were the German U-boats fitted with the Alberich coating during WWII. The concept was dormant for about forty years. The U.S. Navy first installed Special Hull Treatment (SHT) tiles on the Batfish around 1980, and on all 688-class SSNs after SSN 719 (earlier 688s and some 637s had the tiles retrofitted).

The Ohio class, like other U.S. nuclear submarines, achieves low radiated noise by a combination of technologies. The propulsion machinery is mounted on sound-isolated sub-bases, with flexible connections to the main steam lines, condensers, and shaft. All noise-making equipment is manufactured and balanced such that it produces the minimum noise possible and often can be run at lower speed (or turned off) if full capacity is not needed. The inside of the hull is covered in damping material. All of these technologies were developed in the late 1950s for the Skipjack and Thresher classes and probably more, classified developments have occurred since then.

The anechoic coating probably only minorly contributes to radiated noise reduction and primarily serves to reduce the submarine's target echo strength (i.e., it is analogous to RAM on aircraft). The Ohio class, having first entered service before SHT was available, would have had to be retrofitted with it, which would be expensive and add considerable weight. If an Ohio-class submarine is in a position that it needs a hull coating to avoid an ASW ship or helicopter dipping sonar, it is already in deep trouble. That the Ohio-class SSGNs (which operate in areas where active sonar would be a more considerable concern than for an SSBN) remain uncoated suggests to me that the class may not have the weight/stability margins to install a hull coating. However, the Columbia class apparently will have a hull coating.
 

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