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

Here’s the report
news.usni.org

GAO Report on Columbia-class Submarine Program - USNI News

The following is the January Government Accountability Office report, Columbia-class Program Lacks Essential Schedule Insight amid Continuing Construction Challenges. From the report What GAO Found The Navy plans to deliver the first, or lead, Columbia class submarine—the largest and most...
news.usni.org news.usni.org
 
I assume it could be done at the cost of overall performance. It would delay the program if such a change were introduced now but perhaps it can be worked into later boats.
 
bobbymike said:
View: https://m.youtube.com/watch?v=KZuWSDsqC_0&pp=ygUPQ29sdW1iaWEgY2xhc3Mg

Each quad pack is its own section that could mean easier to add one or two sections 4-8 addition missiles to (20-24 total) to future boats if required? Or would this introduce too much structural change?
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It'll mess with how big the ballast tanks need to be on each end of the ship, which would greatly mess up the shape of the stern. pi*R^2*h says that a single quad is some 1200 tons additional submerged displacement (13m beam times about 9m long).
 
Interestingly the Columbia project had a six month project contingency buffer but while the first submarines delivery is not currently running late that six month buffer has been completely eroded so they want to try and speed up early fabrication to try and recoup it again in case they run into problems during systems installation or commissioning.
 
WatcherZero said:
Interestingly the Columbia project had a six month project contingency buffer but while the first submarines delivery is not currently running late that six month buffer has been completely eroded so they want to try and speed up early fabrication to try and recoup it again in case they run into problems during systems installation or commissioning.
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Because a first in class ALWAYS has issues during sea trials. ALWAYS.
 
Apparently the US is looking for help from the British supply chain to produce castings for the Columbia class due to the limited capacity of the US casting sector.

www.defensenews.com

Navy takes early steps with Australian, UK vendors on shared sub work

The U.S. Navy is increasing its submarine work with Australian and British firms, even as it awaits passage of four key measures to enable AUKUS.
www.defensenews.com www.defensenews.com
 
www.stripes.com

Gecko Robotics to speed submarine construction for US Navy

Rear Adm. Scott Pappano came to Gecko Robotics’ North Side headquarters with a billion-dollar problem: The U.S. Navy needed a faster way to build submarines. Gecko’s dexterous robots — which generate millions of data points as they traverse industrial equipment checking for cracks, corrosion and...
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Firefinder said:
https://twitter.com/x/status/1745116671109455987
View: https://twitter.com/CovertShores/status/1745116671109455987


Image of the Colombia stern showing off her X tail.
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Grumble.

Still don't like the X-tail for a boomer. Because of how the surfaces have to mix, you cannot get the equivalent of full dive on the stern planes and hard rudder. You know, basic torpedo evasion maneuvers. Because Fast Attacks are smaller and spend more time at periscope depth, the X-planes are appropriate for them.
 
Scott Kenny said:
Grumble.

Still don't like the X-tail for a boomer. Because of how the surfaces have to mix, you cannot get the equivalent of full dive on the stern planes and hard rudder. You know, basic torpedo evasion maneuvers. Because Fast Attacks are smaller and spend more time at periscope depth, the X-planes are appropriate for them.
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Overall agility is better across the full range of operating conditions, and less chance of a plane getting stuck/damaged in such a way it cripples the ability of the boat to maneuver. And better flow noise characteristics.
 
Scott Kenny said:
Grumble.

Still don't like the X-tail for a boomer. Because of how the surfaces have to mix, you cannot get the equivalent of full dive on the stern planes and hard rudder. You know, basic torpedo evasion maneuvers. Because Fast Attacks are smaller and spend more time at periscope depth, the X-planes are appropriate for them.
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You can, the control surfaces function identically but offset by 45 degrees, any manoeuvre you can do with a cross you can do with an X with the twin advantages of shallower draft and greater rudder effectiveness for the same surface area as they are in a cleaner waterflow, meaning if you keep them the same size you have larger dive and turning force due to a greater rudder bite, or you can shrink them to reduce noise signature while maintaining the same level of control.
 
WatcherZero said:
You can, the control surfaces function identically but offset by 45 degrees, any manoeuvre you can do with a cross you can do with an X with the twin advantages of shallower draft and greater rudder effectiveness for the same surface area as they are in a cleaner waterflow, meaning if you keep them the same size you have larger dive and turning force due to a greater rudder bite, or you can shrink them to reduce noise signature while maintaining the same level of control.
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No, they don't.

Full dive on the planes puts all 4 surfaces with trailing edges down. Hard rudder requires two surfaces trailing edge up.
 
However rather than just two surfaces contributing to the horizontal and two contributing to the vertical you now have four surfaces contributing to both manoeuvre, this increases the manoeuvring force by 28% over a cross stern. The primary diving moment should be generated from the fore planes anyway, you need to get the nose down to perform a sharp dive, if your submarine is diving while level thats increased water resistance. Thats why foreplanes are better than sail planes, the only advantage of sail planes is manoeuvring in shallow water or docking with the quay until retractable planes were invented.

X_stern[1].png
 
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What do they do with it once it gets to Quonset Point? They don't appear to have a dry dock.
 
sferrin said:
What do they do with it once it gets to Quonset Point? They don't appear to have a dry dock.
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Looks like they probably install the propulsor and control surfaces that make the stern into a complete super-module (SM6). Quonset also assembles a bunch of the other SMs, including the bits of the bow that come from NNS. Then all the super-modules ship to Groton for final assembly and launching. This all happens at land-level facilities; they don't need a dry-dock at Quonset Point.

That's how it's worked for quite a while -- Quonset builds (and now outfits) hull rings/blocks/modules and ships them over to EB Groton for the final steps.

Edit: Here's a couple of images/sources that may help.

1704982157589.png
Source: https://www.gao.gov/assets/gao-18-158.pdf

1704982478766.png
Source: http://columbia-class.com/default.asp
 
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Josh_TN said:
That might explain the downsize to 16 missiles…the new propulsion takes up more volume.
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They cut the number of missiles because they dont need a load of empty tubes, the Ohio class when first built had 24 Trident tubes but that was cut to 20 tubes while only 12 nuclear armed Trident missiles are carried as standard nowadays. So even cutting its capacity to 16 doesn't degrade their operating firepower still leaving 4 spare tubes for other uses such as diver equipment.
 
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Scott Kenny said:
Huh, based on that the reactor is a lot farther forward than on the Ohios, and the engine room is longer.
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The machinery spaces are larger due to the electric drive, life-of-boat reactor, and additional quieting. The reactor itself is further forward due to the reduced missile count meant to conform to arms control/reduction.
 

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