Virginia Sonar Questions

[Halcyon]

I've noticed a couple discrepancies concerning the Virginia class US sub in the USNI reference files.

For the Virginia class, the starboard and port towed array names appear to be accidentally swapped in the ownship section reference page.

Also, the RA mod lists the Virginia's SPHERE sonar to be slightly more sensitive than the Seawolf's SPHERE sonar, but with a lower washout max speed.
I thought that the Virginia was designed to have better sensors than the Seawolf?
Its HULL sonar isn't as good as the Seawolf's, and it has a lower washout max speed for its WAA vs the Seawolf's WAA.

(data taken from the RA mod USNI reference pages. Speed in kts are usable max speed before washout, and the number after is the SNR, i.e. -13)





It doesn't specifically list it in the USNI reference area, but the Virginia is supposed to have the BQQ-10(v4) sonar suite, which is the exact same suite that the 688i has, according to internet sources like those below:

Virginia specifications - https://www.naval-technology.com/projects/nssn/

688i specifications - https://www.naval-technology.com/projects/la/

If that's true, why aren't the MF Active, Sphere, and Flank (hull) sonar values the same?
I don't know if the BQQ-10 suite is supposed to be better than the Seawolf's BSY-2 suite, but in the stock 1.04 DW version, the Seawolf could passively hear a lot further with its sonar than the 688i could.

I would expect the Virginia to improve on that sensor range, but I don't know how to verify if the RA mod actually did that.

[Kapitan]

In real life the Virginias sonars will be more advanced with more up to date hydrophones so would stand to reason they are a little more sensitive.
Being sensitive id fully expect the washout speed to be slightly lower as well, from what I am told by guys on the boats the Virginia sonar is better than the seawolf in many areas.

Dont forget that Virginia is pretty much a brand new unit while the seawolf is 20+ years old its already 2/3 through its life span roughly.

Hydrodynamics will also play a part, the Virginia has the VLS system and a chin array installed and the seawolf doesn't again this has an affect on sonars with regards to the build but critically water flow over the chin array.
To give you some scope the Trafalgar's which had the sonar spike on the bow also encountered some resonance in the sphere array, this was since re done on the astute to cancel it out.

With regards to the MF Active the Virginia may well use the same hardware system but its going to be the software package that makes all the difference and looking at this the Virginia is using the V4 which looks to me like a major software upgrade.

The swap over of the towed array data is probably an accident, there's still some bugs with the RA 151.7 and fixes.

The seawolf sonar was specially designed for that class of boat and designed very specifically for anti submarine warfare, you also need to factor in the 688 and Virginia have a different mission package to the seawolf.
The 688 and Virginia are more general purpose submarines where as the seawolf is a pure hunter killer like the astutes.

BSY-2 is a generation ahead of the older BQQ10 systems the 688s employ, whilst the BQQ10 V4 is an evolution on the older BQQ10

This is limitedly modeled in game as true values are classified but id expect to see seawolf remaining at the top followed by the virginia only slightly behind then the 688's.

The modder has also taken into account hull flow, that chin array and VLS hatches have a slight affect on the sonar capabilities, and also being of an earlier design but upgraded version the limitations that will ultimately be forthcoming.

[Halcyon]

Originally Posted by Kapitan

In real life the Virginias sonars will be more advanced with more up to date hydrophones so would stand to reason they are a little more sensitive.
Being sensitive id fully expect the washout speed to be slightly lower as well, from what I am told by guys on the boats the Virginia sonar is better than the seawolf in many areas.

Dont forget that Virginia is pretty much a brand new unit while the seawolf is 20+ years old its already 2/3 through its life span roughly.

Hydrodynamics will also play a part, the Virginia has the VLS system and a chin array installed and the seawolf doesn't again this has an affect on sonars with regards to the build but critically water flow over the chin array.
To give you some scope the Trafalgar's which had the sonar spike on the bow also encountered some resonance in the sphere array, this was since re done on the astute to cancel it out.

With regards to the MF Active the Virginia may well use the same hardware system but its going to be the software package that makes all the difference and looking at this the Virginia is using the V4 which looks to me like a major software upgrade.

The swap over of the towed array data is probably an accident, there's still some bugs with the RA 151.7 and fixes.

The seawolf sonar was specially designed for that class of boat and designed very specifically for anti submarine warfare, you also need to factor in the 688 and Virginia have a different mission package to the seawolf.
The 688 and Virginia are more general purpose submarines where as the seawolf is a pure hunter killer like the astutes.

BSY-2 is a generation ahead of the older BQQ10 systems the 688s employ, whilst the BQQ10 V4 is an evolution on the older BQQ10

This is limitedly modeled in game as true values are classified but id expect to see seawolf remaining at the top followed by the virginia only slightly behind then the 688's.

The modder has also taken into account hull flow, that chin array and VLS hatches have a slight affect on the sonar capabilities, and also being of an earlier design but upgraded version the limitations that will ultimately be forthcoming.

As usual, top notch informative response. The things you pointed out make sense, especially the software upgrade (in real life).

I don't know how much of that the RA mod simulated, but it sounds like the Virginia is just a better, quieter version of the 688i with more sensitive sonar, even though it's slower.

[Kapitan]

Originally Posted by Halcyon

As usual, top notch informative response. The things you pointed out make sense, especially the software upgrade (in real life).

I don't know how much of that the RA mod simulated, but it sounds like the Virginia is just a better, quieter version of the 688i with more sensitive sonar, even though it's slower.

In lineage the Virginia is the direct replacement to the 688, and for that reason they use what we term as COST boats (Commercial Off Shelf Technology).
With so many 688s in service its has meant the hardware and software is continually upgraded at a higher pace than the seawolf, thus because of this the cost of using this system is cheaper over all. (same in any production process)

This has a direct result on the build and the systems put inside her, the seawolf program was hugely expensive hence why theres only 3 not even the USN could afford post cold war to produce such a submarine.
With the 688 needing replacement the direct driver behind the product was cost.

Seawolf in 1997 cost $3bn per boat, to compare to todays prices $1.69 is what that $1 value was in 1997 so the seawolf if she was built today would be a $5bn boat.
The Virginia is costing $2.8bn per boat right now and this is achieved by using the evolutionary sonar systems from the 688s, and also a lesser grade steel (HY80 as opposed to HY100).
Virginia also incorporates some of the lessons from seawolf such as the modified fin for example.

I cannot comment on top speed or diving capability but what I can say is the pumpjet system is slightly more inefficient than a traditional scewback screw, the advantage though is less rotation v speed which ultimately means a quieter boat over all.

Pumpjet dates back to the 1970's and it was the Royal navy that first deployed them, it uses a system of stators and rotors with a shroud to create thrust, traditional screws used 7 blades the rotor will use 11 blades hence slower rotation to achieve greater speed with less RPM.

The other noticeable advantage is the power output of the reactor, the 688 uses a 6th gen reactor different to seawolf and gives out 165mw in power where as seawolf gives out around 43mw of power from its 6th gen reactor the Virginia with its 9th gen reactor 210mw.

This shows just how much power the hotel load is onboard, it also shows limitations in the design, the type 45 DDG has power problems because its hotel load is always in the high 90%s hence why they have issues but with PIP upgrades that will bring it down to around the 70 mark.
The reason why Seawolf even with a 6th gen reactor only uses 43mw is because it doesn't have to run a VLS system and its associated sub systems.

The Virginia is future proof she has a lot of spare capacity to take future technology both hardware and software.

Overall the modder who makes RA has taken all the above into account, which is why you have the figures above.
In terms of realism I would say the RA mod is about 65-70% accurate, naturally the true figures are classified.

[Halcyon]

Originally Posted by Kapitan

In lineage the Virginia is the direct replacement to the 688, and for that reason they use what we term as COST boats (Commercial Off Shelf Technology).
With so many 688s in service its has meant the hardware and software is continually upgraded at a higher pace than the seawolf, thus because of this the cost of using this system is cheaper over all. (same in any production process)

This has a direct result on the build and the systems put inside her, the seawolf program was hugely expensive hence why theres only 3 not even the USN could afford post cold war to produce such a submarine.
With the 688 needing replacement the direct driver behind the product was cost.

Seawolf in 1997 cost $3bn per boat, to compare to todays prices $1.69 is what that $1 value was in 1997 so the seawolf if she was built today would be a $5bn boat.
The Virginia is costing $2.8bn per boat right now and this is achieved by using the evolutionary sonar systems from the 688s, and also a lesser grade steel (HY80 as opposed to HY100).
Virginia also incorporates some of the lessons from seawolf such as the modified fin for example.

I cannot comment on top speed or diving capability but what I can say is the pumpjet system is slightly more inefficient than a traditional scewback screw, the advantage though is less rotation v speed which ultimately means a quieter boat over all.

Pumpjet dates back to the 1970's and it was the Royal navy that first deployed them, it uses a system of stators and rotors with a shroud to create thrust, traditional screws used 7 blades the rotor will use 11 blades hence slower rotation to achieve greater speed with less RPM.

The other noticeable advantage is the power output of the reactor, the 688 uses a 6th gen reactor different to seawolf and gives out 165mw in power where as seawolf gives out around 43mw of power from its 6th gen reactor the Virginia with its 9th gen reactor 210mw.

This shows just how much power the hotel load is onboard, it also shows limitations in the design, the type 45 DDG has power problems because its hotel load is always in the high 90%s hence why they have issues but with PIP upgrades that will bring it down to around the 70 mark.
The reason why Seawolf even with a 6th gen reactor only uses 43mw is because it doesn't have to run a VLS system and its associated sub systems.

The Virginia is future proof she has a lot of spare capacity to take future technology both hardware and software.

Overall the modder who makes RA has taken all the above into account, which is why you have the figures above.
In terms of realism I would say the RA mod is about 65-70% accurate, naturally the true figures are classified.

Thanks for the breakdown!

I had always assumed the Virginia was an all-over upgrade from the Seawolf, given the Seawolf's age, but it's nice to see that just as in real life, RA retained the Seawolf's fast attack advantages over the Virginia and they're used for completely different mission profiles.

Good stuff.