SSN (X) - Seawolf Redux or something far larger?

Rear Adm. Jon Rucker, PEO for attack submarines, speaking Nov 7 at the Naval Submarine League’s annual symposium


Next-gen attack sub
The Navy intends to begin buying its SSN(X) attack submarine about a decade from now, following what would be a 35-year run building the Virginia-class boats.
Rear Adm. Jon Rucker, the program executive officer for attack submarines, said his team is conducting technology development and early design work. They’ll incorporate the best of the Virginia, Seawolf and Columbia submarine designs and focus on four attributes: speed, payload capacity, stealth and operational availability — minimizing time needed for major depot work and maximizing the time it can be out on patrol.
Rucker said Nov. 7 at the same conference that Navy leadership signed the SSN(X) initial capabilities document, which is now with the Joint Staff for final signatures and approvals.
The Navy will then begin an analysis of alternatives in 2024, he said, noting this process will help decide how to proceed — a clean-sheet design, modifying the existing Virginia-class design, or something in between.
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https://www.defensenews.com/naval/2...es-leveraging-cloud-computing-for-submarines/
 
I heard they were leaning into a premium Seawolf like design but in small numbers of only upto a dozen or so with the bulk of the combat fleet being Virginias/similar capability replacement. They would only have one shipyard assembly line producing them at a low rate.
 
Moose said:
Not surprised to see vertical tube(s) in the bow, little surprised to see a couple in the pressure hull. And both appear to be launching hypersonic CPS missiles. Still just concept art, but interesting.
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The dihedral* (upward angled) bow planes are kinda weird. Never seen that before.

* Yes, a true dihedral. The stern "dihedral" stabilizer fins on modern US subs are actually anhedral. Trust bubbleheads to get "up" and "down" backwards.
 
Im mystified by HI Sutton crapping on the bow payload tubes. It's a tidy, low-cost arrangement that fits how the USN uses its boats.
 
TomS said:
The dihedral* (upward angled) bow planes are kinda weird. Never seen that before.
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Looks like they're planning on the sub being in rough water a lot when at periscope depth. Dihedrals increase righting moment when banking or getting rolled.


TomS said:
* Yes, a true dihedral. The stern "dihedral" stabilizer fins on modern US subs are actually anhedral. Trust bubbleheads to get "up" and "down" backwards.
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The guys on the Seawolf called them anhedrals.
 
Scott Kenny said:
Looks like they're planning on the sub being in rough water a lot when at periscope depth. Dihedrals increase righting moment when banking or getting rolled.



The guys on the Seawolf called them anhedrals.
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Wouldn‘t Sail Planes then not make more sense?
 
Moose said:
Im mystified by HI Sutton crapping on the bow payload tubes. It's a tidy, low-cost arrangement that fits how the USN uses its boats.
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It limits the capacity of the torpedo magazine and firepower, all three are competing for space. Suggests that like the Virginia it might have a low number of torpedo stores compared to the Seawolf or Astute, also only 4 tubes limits the number of targets you can simultaneously prosecute to two vs 6 tubes meaning you can instantly put two torpedoes on three different targets or the number of surface targets you can perform a surprise attack on.
 
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Moose said:
Im mystified by HI Sutton crapping on the bow payload tubes. It's a tidy, low-cost arrangement that fits how the USN uses its boats.
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Not sure what Sutton's exactly saying (was it in a tweet somewhere?), but doesn't this take away from the whole "superior undersea predator stalking PRC/RU submarine and surface groups" mission profile SSN(X) is supposed to be for?

Having CPS-capable tubes (which are by no means small), bow or midship, means SSN(X) may become yet another long-range land attack weapon. Fine I guess, if it doesn't compete with the main mission focus (which WatcherZero mentions in the reply previous to mine as a risk) and CPS gets cheap enough, but at current prices it may be something better left to the Virginia Block Vs, or those Large Payload Submarines that may grow from the Columbia class...unless this is an attempt to obviate the need for the Large Payload Submarine, which might just induce another cost spiral on SSN(X) if not careful.
 
WatcherZero said:
It limits the capacity of the torpedo magazine and firepower, all three are competing for space. Suggests that like the Virginia it might have a low number of torpedo stores compared to the Seawolf or Astute, also only 4 tubes limits the number of targets you can simultaneously prosecute to two vs 6 tubes meaning you can instantly put two torpedoes on three different targets or the number of surface targets you can perform a surprise attack on.
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The bow tubes are sitting in a ballast tank, not the weapons room, and USN tubes are already angled around the bow sonar. A Block III-onward boat has 4 horizontal tubes and 2 vertical payload tubes packed in a 10m beam, a -21 has a 12m beam and SSN(X) may be 13m if they're re-using SSBN tooling. That's plenty of elbow room for 6 + 2 of so desired. The balance of the weapons load on a boat this big can still favor a large torpedo armament while retaining payload tubes for an expanded mission set.
 
longitudinalplansection3.jpg

The vertical tubes take up most of the room behind the sonar leaving a very small weapons room on the Virginia class.
Seawolf had 50 stores in its torpedo room, Virginia due to its arrangement has only 25 but less if carrying special forces as they bunk in there in the empty torpedo racks by carrying fewer weapons as it doesnt have spare bunk space elsewhere in the sub.
 
WatcherZero said:
longitudinalplansection3.jpg

The vertical tubes take up most of the room behind the sonar leaving a very small weapons room on the Virginia class.
Seawolf had 50 stores in its torpedo room, Virginia due to its arrangement has only 25 but less if carrying special forces as they bunk in there in the empty torpedo racks by carrying fewer weapons as it doesnt have spare bunk space elsewhere in the sub.
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Again, the payload tubes external to the pressure hull aren't dictating the torpedo room size. That volume behind the sonar exists because USN boats are single hulled which feature large ballast tanks fore and aft. Over the course of 688 construction, they gained storage for a massive long-line towed arrays in their aft tank, and the forward tank gained VLS without affecting their weapons load in the pressure hull. That VLS carried to SSN-774 then transitioned to Payload Tubes in Block III.

Yes, Seawolf sports a lot of torpedo space. A -774 is narrower than a -21, and the latter has essentially stacked 2 weapons rooms on top one another. Columbia has a hull of even larger diameter, if SSN(X) rings are the same size there will be room for both.
 
WatcherZero said:
longitudinalplansection3.jpg

The vertical tubes take up most of the room behind the sonar leaving a very small weapons room on the Virginia class.
Seawolf had 50 stores in its torpedo room, Virginia due to its arrangement has only 25 but less if carrying special forces as they bunk in there in the empty torpedo racks by carrying fewer weapons as it doesnt have spare bunk space elsewhere in the sub.
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Seawolf's magazine depth had nothing to do with the length of the magazine spaces behind the torpedo tubes, her magazine was spread across two decks and the submarine had a wider diameter pressure hull, hence the magazine spaces were wider. She still had some volume between the front of the pressure hull and sonar sphere, and given that modern US submarine bow sonars are now conformal, there should be more volume still for payload modules.
 
TomS said:
The dihedral* (upward angled) bow planes are kinda weird. Never seen that before.

* Yes, a true dihedral. The stern "dihedral" stabilizer fins on modern US subs are actually anhedral. Trust bubbleheads to get "up" and "down" backwards.
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Someone may be pulling my leg, but apparently the proper term for the stern planes is "negative dihedral" planes and they're shortened to "dihedral" for brevity's sake.
 
Moose said:
Someone may be pulling my leg, but apparently the proper term for the stern planes is "negative dihedral" planes and they're shortened to "dihedral" for brevity's sake.
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I've seen that as well. It doesn't speak well of the NavArch who came up with it, vive that "anhedral" was right there but I'd believe it.
 
quincy said:
Wouldn‘t Sail Planes then not make more sense?
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Sail planes cause issues with under-ice operations. 637s had sail planes that could go vertical to bust through ice, but IIRC the early 688s were not rated for under ice operations until the flight with bow planes.



Moose said:
Again, the payload tubes external to the pressure hull aren't dictating the torpedo room size. That volume behind the sonar exists because USN boats are single hulled which feature large ballast tanks fore and aft. Over the course of 688 construction, they gained storage for a massive long-line towed arrays in their aft tank, and the forward tank gained VLS without affecting their weapons load in the pressure hull. That VLS carried to SSN-774 then transitioned to Payload Tubes in Block III.

Yes, Seawolf sports a lot of torpedo space. A -774 is narrower than a -21, and the latter has essentially stacked 2 weapons rooms on top one another. Columbia has a hull of even larger diameter, if SSN(X) rings are the same size there will be room for both.
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I still don't get why the Seawolfs didn't have any VLS up forward, but I fully expect the SSNX to have a few. Maybe even 4x VPMs if they use the big Columbia class hull rings.
 

New Images Of U.S. Navy's Next Attack Submarine, SSNX​

From: http://www.hisutton.com/US-Navy-SSNX-2023.html

As is becoming customary, a comnpany video by an American submarine builder gives us the latest glimpse of future submarine projects. A video published by Electric Boat shows two graphics of the U.S. Navy’s next generation SSNX boat.

1703361800227.png

SSNX will follow the successful Virginia class into service. It is expected to carry hypersonic missiles and refocus on submarine-submarine warfare. In some respects it is a return to the Seawolf Class ethos, just with land attack added.

1703361774773.png

It is difficult to judge how representing the graphics are. Some design features are as expected, including the sail shape and x-form rudders with fixed leading elements. But other design choices appear trapped in the Virginia class. The vertical launch system ahead of the sail is retained even though it was something of a workaround in the first place. And the torpedo tubes appear few (perhaps only 4) and in the chin position shooting around the VLS and sonar. One might think that a new design, with modern conformal sonar, could relocate the torpedo tubes shooting forward.

However, at the moment this visualization is the best we have. For sure the SNNX, whatever it looks like, will be a top tier underwater predator.
 
Ironmiked said:

New Images Of U.S. Navy's Next Attack Submarine, SSNX​

From: http://www.hisutton.com/US-Navy-SSNX-2023.html

As is becoming customary, a comnpany video by an American submarine builder gives us the latest glimpse of future submarine projects. A video published by Electric Boat shows two graphics of the U.S. Navy’s next generation SSNX boat.

View attachment 714821

SSNX will follow the successful Virginia class into service. It is expected to carry hypersonic missiles and refocus on submarine-submarine warfare. In some respects it is a return to the Seawolf Class ethos, just with land attack added.

View attachment 714820

It is difficult to judge how representing the graphics are. Some design features are as expected, including the sail shape and x-form rudders with fixed leading elements. But other design choices appear trapped in the Virginia class. The vertical launch system ahead of the sail is retained even though it was something of a workaround in the first place. And the torpedo tubes appear few (perhaps only 4) and in the chin position shooting around the VLS and sonar. One might think that a new design, with modern conformal sonar, could relocate the torpedo tubes shooting forward.

However, at the moment this visualization is the best we have. For sure the SNNX, whatever it looks like, will be a top tier underwater predator.
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Another reason for dihedral bow planes is to make them perpendicular to the hull at the point they connect. This simplifies the flow around them, no fairings or anything to mess up the hull shape. Half the reason the old F4U Corsair had inverted gull wings.

I gotta admit, I was expecting the forward VLS. This image suggests only two VPMs forward, despite the large hull diameter. A 43ft diameter hull has enough volume for VPMs to be mounted side by side, so you could seriously have 4x VPMs forward for 12x 21" and 6x 36" weapons.

Only two torpedo tubes visible on this image means only 4 total, which is lower than I expected. I was honestly expecting a slightly redesigned Seawolf forward compartment to fit onto the Columbia class engineroom, so a double sized torpedo room and 8x tubes, with 2x VPMs forward for Tomahawks etc. Seawolf is 3ft smaller in diameter than Columbia, which adds a LOT of volume.

Having more VLS tubes amidships is a surprise. I was not expecting amidships VLS until the Large Payload Submarine.

The old WAA instead of the larger LVAs is very strange, seems like a step backwards.

The other strange detail is a lack of stealth shaping in terms of flat planes to only reflect sound in specific directions, like on the Astute class.
 
Scott Kenny said:
You don't need 50 weapons to go SSBN hunting.

You do need 50 weapons to go carrier group hunting.
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The deep magazine was to ensure that Seawolf could remain on station for longer, without having to cross anti-submarine barriers patrolled by other NATO submarines, reducing the chance of friendly fire and thus increasing survivability.
 
Scott Kenny said:
The other strange detail is a lack of stealth shaping in terms of flat planes to only reflect sound in specific directions, like on the Astute class.
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Maybe the reasoning is that the extra weight and cost is not worth it when, if the opponent is using active sonar, they're detectable at twice the range that the SSNX is.

Maybe there's something exotic like active sound cancelling.

Alternatively, as with the NGAD, these are an early design iteration that is similar to but not identical with what will eventually emerge, or they are deliberately inaccurate.
 
Scott Kenny said:
You don't need 50 weapons to go SSBN hunting.

You do need 50 weapons to go carrier group hunting.
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The -21s carried a big torpedo armament because they were going to stay in Soviet waters for extended periods without coming out for replenishment.
8 tubes too.
They would have gone after SSNs/SSGNs too.
 
Bruno Anthony said:
The -21s carried a big torpedo armament because they were going to stay in Soviet waters for extended periods without coming out for replenishment.
8 tubes too.
They would have gone after SSNs/SSGNs too.
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Certainly.

8 tubes means that they can engage multiple targets easily. Subs get 2x Mk48s, anything on the surface gets 1x. Always save at least one tube for a snapshot at someone you didn't detect until they launched at you.

And subs generally operate alone, because it's difficult to coordinate while submerged.
 
that_person said:
From what I understand Russia and China still rely on wolfpack tactics.
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Maybe against surface convoys, since everyone will be at or near periscope depth for the attacks. Much easier to coordinate when your target is a known location and all of your hunting buddies can be known locations.

But when going after another submarine? Singles. otherwise you risk friendly fire from the utter lack of IFF underwater.

I only trained against singles in the early 2000s.
 
Needs to be pointed out thst the Seawolves were expect to go out with the tube launch Tomahawk and Harpoons. And still do as far as I know.

As were their previous designs after the Tomahawk came out then before that there were the special sub only weapons like UGM-89 Perseus STAM. So it is a strange thing that the Seawolf lacked VLs.

The US been trying to have a big deep diving attack sub with a metric asston of tubes since at least the early 1970s as seen by the Advanced Performance High-speed Nuclear Attack Submarine (APHNAS) concept of 1970 to 74.

Likely be seeing a similar design set up for tge SSN[x] before its pruned downed for budget.
 

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