NSSN Virginia-class - current status and future

[Triton]

Were there any other concepts for the NSSN before the Virginia-class configuration was approved?

 

[Just call me Ray]

Wow, someone's been posting a lot!

There were a lot of concepts for NSSN. A few of them tried for the more conventional approach, similar to what eventually became the Virginia. Some of them had a hull shape more in common with Russian designs, with the smoothed-over sail. A few others were more artists' conjecturals more than anything else with bizarre, "super-hydrodynamic" shapes and equipped with its own mini-fleet of seagoing unmanned vehicles.

 

[Triton]

Wow, someone's been posting a lot!

There were a lot of concepts for NSSN. A few of them tried for the more conventional approach, similar to what eventually became the Virginia. Some of them had a hull shape more in common with Russian designs, with the smoothed-over sail. A few others were more artists' conjecturals more than anything else with bizarre, "super-hydrodynamic" shapes and equipped with its own mini-fleet of seagoing unmanned vehicles.

Thanks for the response. I recently discovered this web site and had many questions. Where might I find information about the NSSN concepts?

 

[Just call me Ray]

PopSi and PopMech had some articles, but I cannot recall the specific issues.

 

[fightingirish]

There were a lot of concepts for NSSN. A few of them tried for the more conventional approach, similar to what eventually became the Virginia. Some of them had a hull shape more in common with Russian designs, with the smoothed-over sail. A few others were more artists' conjecturals more than anything else with bizarre, "super-hydrodynamic" shapes and equipped with its own mini-fleet of seagoing unmanned vehicles.

The attached pic is taken from a cover of the Popsi magazine.

 

[XP67_Moonbat]

I think "All Hands" magazine ran a picture like that back then. I'll have to see if I still have it.

Moonbat

 

[Triton]

Thank you fightingirish, whatever would we do without Popular Science magazine. ;D

 

[TomS]

I'm fairly sure that's not actually a pre-NSSN concept, but rather a concept for the Advanced Sail, which may show up in later years production of the Virginia class.

For a survey of several other NSSN successor designs proposed back around 2002, see this PDF of an article from International Defense Review:

http://www.kentaurus.com/downloads/IDRSub.pdf

 

[fightingirish]

The Block III Virginia-class submarines which will feature a revised bow, including some technology from Ohio class SSGN's.
Block III bow mods
(click to view full)
Source: Defense Industry Daily - Virginia Block III: The Revised Bow - 21-Dec-2008 13:28 EST

 

[Just call me Ray]

I have to wonder if a Virginia can be used as an SSBN in that manner. I doubt a Trident would fit, but a purpose-designed missile would.

 

[Demon Lord Razgriz]

I've looked all over and I can not find the US alphanumerical designation of the VLS system used in the Virginia-Class SSN. Does anyone here have a clue as to what it is?

 

[F-14D]

I've looked all over and I can not find the US alphanumerical designation of the VLS system used in the Virginia-Class SSN. Does anyone here have a clue as to what it is?

Unlike the Mk 41 designation for surface ship VLS, I don't believe there is a numerical designation for sub use. They seem to simply be referred to as "Submarine VLS" or "VLS tubes", because they're basically just tubes.

Starting with SSN 784 the 12 tubes of the previous VLS will be replaced by two of what's called the "Virginia Payload Tube". This is very similar to the tubes in the Ohio SSGNs except that each tube will house six rather than seven missiles (the center will now house an access tube). The VPT's can be loaded with modular systems (called canisters), which will allow greater versatility relative to the pure VLS. Don't know if this will have a designator.

 

[Demon Lord Razgriz]

So the US Military has given up a chance to add a alphanumerical designation to a weapons system!?!

I never thought that could happen with their love of alphanumerical designation!

 

[F-14D]

So the US Military has given up a chance to add a alphanumerical designation to a weapons system!?!

I never thought that could happen with their love of alphanumerical designation!

Since the Virginia VPT is so unique (unlike the Mk41 which was deployed on a variety of platforms and so basic, maybe they didn't thing a designator was necessary? Now, one wonders if the canisters might get designators.

 

[Triton]

Virginia-class Batch 3 / Block IV

 

[F-14D]

Virginia-class Batch 3 / Block IV

According to something I read in the Naval Institute Proceedings, I believe, some years back, Seawolf, and its successor were originally planned to have a sail much like depicted here. However, according to the article, powers that be thought it would make the boat look too much like a Soviet sub, and there were objections at the high levels. As a result, the design was changed, and all that remains of the original design is the little fillet at the for end of tghe sails of the Seawolf and Virginia classes.

Stranger things have happened.

 

[Triton]

Virginia-class Batch 3 / Block IV

According to something I read in the Naval Institute Proceedings, I believe, some years back, Seawolf, and its successor were originally planned to have a sail much like depicted here. However, according to the article, powers that be thought it would make the boat look too much like a Soviet sub, and there were objections at the high levels. As a result, the design was changed, and all that remains of the original design is the little fillet at the for end of tghe sails of the Seawolf and Virginia classes.

Stranger things have happened.

Interesting. The concept has some resemblance to the Soviet/Russian Bars/Shuka B Type 971 (NATO "Akula") class attack submarine. I wonder what the possibility would be that it would be mistaken for an "Akula" class on the surface?
http://www.fas.org/man/dod-101/sys/ship/row/rus/971.htm

 

[Firefly 2]

It really depends on the training of the sighting crew, me thinks. Chances are that it could happen, and it wouldn't be the first miss-identification by military personnel. It remains a nice design from a purely aesthetic point of view though.

 

[sferrin]

Virginia-class Batch 3 / Block IV

According to something I read in the Naval Institute Proceedings, I believe, some years back, Seawolf, and its successor were originally planned to have a sail much like depicted here. However, according to the article, powers that be thought it would make the boat look too much like a Soviet sub, and there were objections at the high levels. As a result, the design was changed, and all that remains of the original design is the little fillet at the for end of tghe sails of the Seawolf and Virginia classes.

Stranger things have happened.

I'd be happy if they brought the build quality back up above 3rd world standards.

 

[flateric]

Composite Advanced Sail configurations, studied for Virginia Block IV in late 90s

sources
http://ftp.rta.nato.int/public//PubFullText/RTO/MP/RTO-MP-089///MP-089-33.pdf
http://ftp.rta.nato.int/public//PubFullText/RTO/MP/RTO-MP-089///PowerPoint%20Slides/MP-089-33.pps

Var 1





Var 2











scaled to 1/4 Advanced Sail tests onboard LSV Kokanee in 1999



макет Advanced Sail



Virginia with AS (high-res version)



Virginia command post



another redesigned bow Virginia render

 

[Aeroengineer1]

From what I have been able to gather, the "advanced" sail concept is quite difficult. It creates some very large vorticies off the front that get ingested into the proplusor and create acoustic issues. The main reason for wanting to go to this concept is to get more room in the sail for other toys such as a faired in launch and storage area for larger uuv's and to move the command center of the boat up higher in the structure. The fairing that is currently on the sail was originally proposed for the LA class, though it was never implemented (it may have been tested though, I have a factory drawing of it which is authentic). I would actually be surprised to see this sail get implemented as even the newer Russian boats are moving away from the faired sail. There are a lot of interesting things that have been proposed for the spiral upgrades of the boat, though I think that most of them will not make it into the final configuration. Some of these things include the distributed pump jet propulsor, the rim driven electric propulsor, the x stern configuration, the advanced sail, and of course the new bow changes in this latest round. As far as what I have been able to read, it appears that the rim driven propulsor will eventually get included, then perhaps the sail, then the x tail, and last would be the distributed pump jet (which would get rid of the stern planes all together).

Adam

 

[flateric]

Some of the stuff Adam was talking about + looking even further in the future

 

[Firefly 2]

That's wonderfull material! Thank you!

 

[F-14D]

It really depends on the training of the sighting crew, me thinks. Chances are that it could happen, and it wouldn't be the first miss-identification by military personnel. It remains a nice design from a purely aesthetic point of view though.

Primary identification would be by sound, of course

 

[TomS]

I wonder what the possibility would be that it would be mistaken for an "Akula" class on the surface?

I very much doubt that there was any concern of a mistaken identification in combat -- modern subs do not fight on the surface, period.

The objection that it looks too much like a Soviet design was likely more one of perception -- that it would give the appearance that the US Navy was having to copy a Soviet design concept. Given that the Soviets sometimes did have an edge in aerodynamics and hydrodynamics, there might be a kernel of truth in that, but the USN would take great pains to avoid making that admission.

 

[Trident]

A NIH thing, in other words

 

[Firefly 2]

It really depends on the training of the sighting crew, me thinks. Chances are that it could happen, and it wouldn't be the first miss-identification by military personnel. It remains a nice design from a purely aesthetic point of view though.

Primary identification would be by sound, of course

I do believe the initial premise of the question I responded to was visual identification, but in all other respects you are of course correct.

 

[F-14D]

It really depends on the training of the sighting crew, me thinks. Chances are that it could happen, and it wouldn't be the first miss-identification by military personnel. It remains a nice design from a purely aesthetic point of view though.

Primary identification would be by sound, of course

I do believe the initial premise of the question I responded to was visual identification, but in all other respects you are of course correct.

Except for entering or leaving port or for swim call, in normal ops no self-respecting SSN is ever going to be caught on the surface. Even then primary ID would still be by sound.

 

[Firefly 2]

It really depends on the training of the sighting crew, me thinks. Chances are that it could happen, and it wouldn't be the first miss-identification by military personnel. It remains a nice design from a purely aesthetic point of view though.

Primary identification would be by sound, of course

I do believe the initial premise of the question I responded to was visual identification, but in all other respects you are of course correct.

Except for entering or leaving port or for swim call, in normal ops no self-respecting SSN is ever going to be caught on the surface. Even then primary ID would still be by sound.

Still not denying the truth in your words.

 

[F-14D]

It really depends on the training of the sighting crew, me thinks. Chances are that it could happen, and it wouldn't be the first miss-identification by military personnel. It remains a nice design from a purely aesthetic point of view though.

Primary identification would be by sound, of course

I do believe the initial premise of the question I responded to was visual identification, but in all other respects you are of course correct.

Except for entering or leaving port or for swim call, in normal ops no self-respecting SSN is ever going to be caught on the surface. Even then primary ID would still be by sound.

Still not denying the truth in your words.

Thanks. You'd think after all this time, though, I'd be able to do a quote correctly.

 

[Aeroengineer1]

I wonder what the possibility would be that it would be mistaken for an "Akula" class on the surface?

I very much doubt that there was any concern of a mistaken identification in combat -- modern subs do not fight on the surface, period.

The objection that it looks too much like a Soviet design was likely more one of perception -- that it would give the appearance that the US Navy was having to copy a Soviet design concept. Given that the Soviets sometimes did have an edge in aerodynamics and hydrodynamics, there might be a kernel of truth in that, but the USN would take great pains to avoid making that admission.

This statement is not quite correct as hydrodynamics are directly related to acoustic of the boat. while it may be true that some of their boats did have lower hull drag, (though a more thorough analysis would be needed to validate this claim), the strong vortexes that develop off of the faired in sail have caused it being delayed in its introduction on the boat. It was originally slated for introduction in the block II boats (or the current boat that is being produced along with the revised bow), but it has been found that it greatly increases its acoustic signature. There have been a few open source papers describing the basic research that has been done on the topic to test it out, and the sail shown on the LSV2 in one of the previous posts is one of those. This sail was not the most ideal in the form of drag, but offered a faired in storage area for uuv's to be stored in the aft portion of the sail and not in the hull.

As for the Russian boats being more hydrodynamic, see that the current generation of Russian boats are mimicking the styling of us boats with long untapered portions in the center section. The "ideal" teardrop shape is about 6-8:1 length over diameter for drag purposes. There is a very sharp drop in drag up to about 5:1 then a very flat section in the curve up to about 9:1 and then a very gentle rise after that (ie almost a straight line). So for a given boat shape the Russians had to make their outer hull even bigger to support a cylindrical pressure hull, where as with the US boat there was only a single hull built to the maximum outer diameter, and hence more space efficient. US boats though tended to have less reserve buoyancy than Russian boats.

Adam

 

[Abraham Gubler]

So for a given boat shape the Russians had to make their outer hull even bigger to support a cylindrical pressure hull, where as with the US boat there was only a single hull built to the maximum outer diameter, and hence more space efficient. US boats though tended to have less reserve buoyancy than Russian boats.

Soviet submarines had significantly more reserve buoyancy than US and western boats because they were designed to be "unsinkable". Unsinkable being the term used to describe a boat being able to recover to the surface with one compartment fully flooded. Considering how many times Soviet submarines had major onboard accidents this was probably a good idea... Of course because western boats were much safer and not having the same degree of accidents it didn't make the Soviet boats 'better' overall.

The Soviets used double hulls because this not only made it easier to provide plenty of buoyancy tanks but also easier to build the pressure hulls as they didn't need to be hydrodynamically shaped on their outside. This was part of the experience brought to the Soviet Union from Germany after WW2 (Type XXI). Of course building a double hulled submarine has major drawbacks in acoustic silencing. The outer hull needs to be heavily 'tuned' if it isn't going to act as an acoustic resonator.

Much of the Soviet submarine experience is finding ways around inherent system fails. Of course with the exception of the Project 705 (NATO: ALFA) the most revolutionary submarine since the Type XXI.

 

[flateric]

Unsinkable being the term used to describe a boat being able to recover to the surface with one compartment fully flooded.

even up to three in case of Typhoon class

 

[Aeroengineer1]

Sadly though, as was seen with the Kursk, there is not too much to defend against a torpedo that is well placed. Avoidance is the best method to be able to come back to the top. (And no I am not saying that it was torped by another boat, just their hot load that went off).

Adam

 

[F-14D]

Sadly though, as was seen with the Kursk, there is not too much to defend against a torpedo that is well placed. Avoidance is the best method to be able to come back to the top. (And no I am not saying that it was torped by another boat, just their hot load that went off).

Adam

In the case of the Kursk, the fact that it went off inside the pressure hull is particularly significant. Outside the hull would change the dynamic somewhat. Whatever else you might say for or against their designs, the Soviets built strong boats. Remember, a Yankee had an SLBM cook off in one of the tubes (no nuclear detonation, of course), yet the sub still managed to surface and stay afloat for three days. I believe it was even traveling under its own power for awhile until it finally went under (after the crew was saved). No comparable US sub would have done as well (of course, since we don't use liquid fuel, we wouldn't have a missile cook off in the first place).

On a related note, the Seawolf class has eight 660 mm torpedo tubes, instead of the 533mm that had been standard for decades before and returned to for the Virginias. Although the USN says they are that big for "stealth reasons, to allow the torpedoes to swim out, that wasn't the only reasons for the big tubes. Back when Seawolf was being designed there was a real concern that the upcoming Soviet subs it was expected to face over its life would be so strong that a near detonation, or maybe even a direct glancing hit might not be enough to cripple one of them. Design work began for a larger diameter, more powerful torpedo that would be carried by Seawolf. That project was terminated, either for cost reasons or further intelligence that indicated the existing torpedo size would be powerful enough after all. The Seawolf design, though, was too far along to make that kind of a substantial change, so they just pressed on with the bigger tubes. After all, they did permit a stealthy swim-out launch.

 

[Austin]

Is there any US Congress or other reports from publication , which shows how Seawolf/Virgina stacks up against Akula-2 specially the Gepard.

Way back in early and mid 90's there were reports from US congress and USN which concluded that Akula-2 has surpassed Improved LA in quietening ... nothing much after that.

 

[sferrin]

Sadly though, as was seen with the Kursk, there is not too much to defend against a torpedo that is well placed. Avoidance is the best method to be able to come back to the top. (And no I am not saying that it was torped by another boat, just their hot load that went off).

Adam

In the case of the Kursk, the fact that it went off inside the pressure hull is particularly significant. Outside the hull would change the dynamic somewhat. Whatever else you might say for or against their designs, the Soviets built strong boats. Remember, a Yankee had an SLBM cook off in one of the tubes (no nuclear detonation, of course), yet the sub still managed to surface and stay afloat for three days. I believe it was even traveling under its own power for awhile until it finally went under (after the crew was saved). No comparable US sub would have done as well (of course, since we don't use liquid fuel, we wouldn't have a missile cook off in the first place).

On a related note, the Seawolf class has eight 660 mm torpedo tubes, instead of the 533mm that had been standard for decades before and returned to for the Virginias. Although the USN says they are that big for "stealth reasons, to allow the torpedoes to swim out, that wasn't the only reasons for the big tubes. Back when Seawolf was being designed there was a real concern that the upcoming Soviet subs it was expected to face over its life would be so strong that a near detonation, or maybe even a direct glancing hit might not be enough to cripple one of them. Design work began for a larger diameter, more powerful torpedo that would be carried by Seawolf. That project was terminated, either for cost reasons or further intelligence that indicated the existing torpedo size would be powerful enough after all. The Seawolf design, though, was too far along to make that kind of a substantial change, so they just pressed on with the bigger tubes. After all, they did permit a stealthy swim-out launch.

See also "micro nukes" for the same reason. The idea of fitting torpedos with 0.020 - 0.050 kt nukes (20 -50 tons) warheads was kicked around.

 

[F-14D]

Is there any US Congress or other reports from publication , which shows how Seawolf/Virgina stacks up against Akula-2 specially the Gepard.

Way back in early and mid 90's there were reports from US congress and USN which concluded that Akula-2 has surpassed Improved LA in quietening ... nothing much after that.

Seawolf is much quieter than an LA class boat, and Virginia, although not carrying as much armament and not being as fast (although reportedly the Virginias have turned out to be significantly faster than expected), at least match the Seawolf in quietness. Of greater significance that the absolutely highest level of quietness is their tactical or "quiet" sped. That's the highest speed at which they can operate and still be below the level of detectability by competitive subs. For most subs, that's something around 3-5 knots. On these two classes, the open literature suggests it's above 20 knots.

That's amazing, but remember, these boats cost a lot of money!

 

[Austin]

I remember reading in Janes that the Akula-2 has high tactical quite speed and their sonars are operational up to 25 knots like Seawolf.

Is there any documented information or any thing from US congress where a Seawolf or Virginia managed to track an Akula-2 ?

 

[F-14D]

I remember reading in Janes that the Akula-2 has high tactical quite speed and their sonars are operational up to 25 knots like Seawolf.

Is there any documented information or any thing from US congress where a Seawolf or Virginia managed to track an Akula-2 ?

The question, of course, is where Jane's s getting its information from these days. Back in the '90s and early 2000s, there were a number of charges flying around that because of staff cutbacks, some of its information was coming from companies' marketing depts.

Keep in mind also that Akula II was designed a long time ago and they've only got a handful. I understand that in addition to its own SSNs, India is paying for completion of two Akula IIs that were never finished due to lack of money, which they will then operate in a lease/buy arrangement.

Regarding who has tracked who, that information is so highly classified by both sides that it'll be a long time, if ever, that we learn about that. Almost anything from the US Congress is going to be shaded for political reasons by whoever wants to be in front of the TV cameras that day, so one would need to verify with other sources.