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

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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Yep.

Anechoic coatings are there for active sonar damping, not really for internal self-noise. If an Ohio is close enough to be getting actively pinged, it's in deep trouble. (pardon the pun)



Vepr157 said:
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.
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Well, look at the difference between submerged and surfaced displacement. An Ohio only takes on like 1200 tons of water!
 
Bruno Anthony said:
Rickover said electric drives beat rafting
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He said no such thing. Rickover was only really interesting in quieting when it aligned with his other priorities (creating new reactor plants, simplifying them, making them more reliable, etc.).

Besides, an electric drive submarine also needs sound-isolation. Even if the motor is not resiliently mounted, the turbine generators will be.
 
Vepr157 said:
He said no such thing. Rickover was only really interesting in quieting when it aligned with his other priorities (creating new reactor plants, simplifying them, making them more reliable, etc.).

Besides, an electric drive submarine also needs sound-isolation. Even if the motor is not resiliently mounted, the turbine generators will be.
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Bullshit he didn’t support nuclear-electric drive.
 
Bruno Anthony said:
He didn’t support nuclear-electric drive.
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That's quite incorrect: Rickover was responsible for the world's first turboelectric submarine, the Tullibee. He also lobbied congress to fund his Turboelectric Drive Submarine (TEDS), which became the Glenard P. Lipscomb. Rickover was very familiar with turboelectric drive because he had a Master's in electrical engineering and had a lot of experience with the turboelectric battleship propulsion plants when he headed the Electrical Section of the Bureau of Ships during WWII.
 
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Vepr157 said:
That's quite rude and quite incorrect: Rickover was responsible for the world's first turboelectric submarine, the Tullibee. He also lobbied congress to fund his Turboelectric Drive Submarine (TEDS), which became the Glenard P. Lipscomb. Rickover was very familiar with turboelectric drive because he had a Master's in electrical engineering and had a lot of experience with the turboelectric battleship propulsion plants when he headed the Electrical Section of the Bureau of Ships during WWII.
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Yet both Tullibee and Glenard P were terrible. horribly slow compared to their steam turbine counterparts.
 
Scott Kenny said:
Yet both Tullibee and Glenard P were terrible. horribly slow compared to their steam turbine counterparts.
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Remember that the counterpart to the Tullibee was not a nuclear submarine, but a diesel SSK. She could make 16 knots on 2,500 SHP, compared with about double the power required to propel a GUPPY or Tang to that speed (of course achievable only at the one-hour rate). She was exceptionally quiet and by all accounts was an excellent ASW and sonar test platform.

And the Lipscomb was merely one of Rickover's propulsion experiments; that she was big and slow was not really a problem. That her propulsion plant was inefficient and unreliable was the bigger issue.
 
Vepr157 said:
That's quite rude and quite incorrect: Rickover was responsible for the world's first turboelectric submarine, the Tullibee. He also lobbied congress to fund his Turboelectric Drive Submarine (TEDS), which became the Glenard P. Lipscomb. Rickover was very familiar with turboelectric drive because he had a Master's in electrical engineering and had a lot of experience with the turboelectric battleship propulsion plants when he headed the Electrical Section of the Bureau of Ships during WWII.
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My post was misunderstood. It’s bullshit that Rickover did not believe that nuclear electrica superior way to quiet than rafting.
 
Bruno Anthony said:
True but he believed according to books around here that nuclear electric was better than rafting alone
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Bibliography, please? (not trying to be confrontational)

Glennard P showed that you needed a reactor plant designed around turbo-electric drive, backfitting it to an existing plant left you slow. turbo-electric drive is about 80% efficient in turning steam into shaft RPM, while turbines and gears are better than that.

In all honesty, the best sub of the 1960s or 70s was the Narwhal, with that crazy multimultistage single main engine directly driving the screw at up to ~350rpm. Reduction gears are the single greatest source of ship noise, as they're directly connected to the shaft and screw that go into the water.
 
Oops, missed this.
Vepr157 said:
Remember that the counterpart to the Tullibee was not a nuclear submarine, but a diesel SSK. She could make 16 knots on 2,500 SHP, compared with about double the power required to propel a GUPPY or Tang to that speed (of course achievable only at the one-hour rate). She was exceptionally quiet and by all accounts was an excellent ASW and sonar test platform.
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She had hideous reliability, and was sarcastically referred to as "Building 597" at Groton due to how little she deployed. "Welded to the pier" was another description.
 
Scott Kenny said:
Oops, missed this.

She had hideous reliability, and was sarcastically referred to as "Building 597" at Groton due to how little she deployed. "Welded to the pier" was another description.
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Many of Rickover's one-off prototypes had similar problems, so I wouldn't read too much into that.
Scott Kenny said:
Glennard P showed that you needed a reactor plant designed around turbo-electric drive, backfitting it to an existing plant left you slow. turbo-electric drive is about 80% efficient in turning steam into shaft RPM, while turbines and gears are better than that.
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For the 1960s-era Lipscomb, but certainly in recent decades lack of efficiency much less of a concern. They don't even use motor-generators anymore; everything is solid-state. You may find this article interesting: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1559-3584.1994.tb02824.x
 
Scott Kenny said:
In all honesty, the best sub of the 1960s or 70s was the Narwhal, with that crazy multimultistage single main engine directly driving the screw at up to ~350rpm. Reduction gears are the single greatest source of ship noise, as they're directly connected to the shaft and screw that go into the water.
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Isn't this an argument in favor of eliminating reduction gears and replacing them with direct drive electric propulsion?

Vepr157 said:
Many of Rickover's one-off prototypes had similar problems, so I wouldn't read too much into that.

For the 1960s-era Lipscomb, but certainly in recent decades lack of efficiency much less of a concern. They don't even use motor-generators anymore; everything is solid-state. You may find this article interesting: https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1559-3584.1994.tb02824.x
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Wow, that was a very fascinating study to read, thank you for linking to it!
 
Scott Kenny said:
Bibliography, please? (not trying to be confrontational)

Glennard P showed that you needed a reactor plant designed around turbo-electric drive, backfitting it to an existing plant left you slow. turbo-electric drive is about 80% efficient in turning steam into shaft RPM, while turbines and gears are better than that.

In all honesty, the best sub of the 1960s or 70s was the Narwhal, with that crazy multimultistage single main engine directly driving the screw at up to ~350rpm. Reduction gears are the single greatest source of ship noise, as they're directly connected to the shaft and screw that go into the water.
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See Friedman books on Subs. US and British.

“That did not happen only because there was no existing motor nearly powerful enough. Admiral Hyman Rickover developed a turbo-electric plant for the Glenard P. Lipscomb specifically to replace what he considered the poorly-engineered raft concept.“

https://www.usni.org/magazines/proc...aval-developments-navy-commits-electric-drive
“He vigorously opposed the use of rafting for silencing- and lost (he wanted to use turbo-electric drive instead; he did win to the extent that GLENARD D. LIPSCOMB was a full-size submarine instead of the proposed SKA TE derivative).”

https://archive.navalsubleague.org/2005/a-further-comment-on-cold-war-submarines
 
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Scott Kenny said:
Yes, now that the US can make a 65,000hp electric motor!
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Is is this one?

“one of the most powerful so far has been developed by Northrop Grumman for the US Navy.

This uses High-Temperature Superconducting coils that make it not only more powerful but much smaller. The HTS Motor is a 36.5 MW equivalent to 49,000 hp and yet it weighs about 75 tons, the amount of torque it generates is 2.13 millon lb-ft.“
 
I'm Kinda expecting "Columbia-class engineroom with Seawolf-like Forward Compartment" for SSNX. Though I also expect a couple of VPM tubes. Maybe not 8 tubes/50 stows in the torpedo room plus 2x VPM, but I wouldn't be surprised by 6 tubes/36 stows in the torpedo room plus the VLS. (~6 stows per tube seems to be pretty consistent with fast attacks from 594s on up till 774s)

While the Ohio-class and Seawolf powerplants are not the same design, they do make about the same horsepower. Change the propulsor from one quietest/most efficient at low speeds to one more capable of sustained high speeds and job's done aft.
For what it's worth, it would be very good for the industrial base to design a new reactor instead of recycling the Columbia's design, but it's not absolutely required (if budgets are still causing issues).​
 
Moose said:
they're accomplishing this ramp-up while also commissioning 2 Block IV SSNs this year
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That's somewhat misleading as the SSN production rate is still stuck at ~1.3-1.4 hulls/year. So mathematically speaking some years they commission 1 SSN and some years 2 SSNs.

There is no discernable ramp-up in deliveries expected until ~2031+, which is their target date to hit ~2 SSNs/year. That plan is based on the hope that after the learning curve of the first 2-3 Virginia Block Vs with VPM they will find efficiencies that will allow them to build the larger Block Vs with VPM as fast as the current Block IVs... which might be a tad optimistic.
 
H_K said:
That's somewhat misleading as the SSN production rate is still stuck at ~1.3-1.4 hulls/year. So mathematically speaking some years they commission 1 SSN and some years 2 SSNs.

There is no discernable ramp-up in deliveries expected until ~2031+, which is their target date to hit ~2 SSNs/year. That plan is based on the hope that after the learning curve of the first 2-3 Virginia Block Vs with VPM they will find efficiencies that will allow them to build the larger Block Vs with VPM as fast as the current Block IVs... which might be a tad optimistic.
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Deliveries will be the lagging indicator. The ramp up is visible in the increased workforce and increased output. Producing 2 Block V boats with VPM and 1 SSBN a year is about equivalent to producing 5 Block IVs. It's not going to happen overnight, but they're heading there.
 

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