Sub Design Comparisons (Virgina and Astute)

[enigmaticuk]

I have noticed a considerable diffence in the deisgn of the latest subs to come from the US and UK navies. The US with the virgina class has a traditional cylindrical design with a conical bow. The UK has the Astute class which has an oval bow and un-cylinrical design. What do these differences in design represent in the subs capabilites it has been puzzling me for some time and i would appreciate any ideas or answers from other users. Appologies for a less than technical description of my comparison and if your not sure what i mean there are plenty of pics availble on the net of both classes of subs.

 

[old faithful]

I have noticed a considerable diffence in the deisgn of the latest subs to come from the US and UK navies. The US with the virgina class has a traditional cylindrical design with a conical bow. The UK has the Astute class which has an oval bow and un-cylinrical design. What do these differences in design represent in the subs capabilites it has been puzzling me for some time and i would appreciate any ideas or answers from other users. Appologies for a less than technical description of my comparison and if your not sure what i mean there are plenty of pics availble on the net of both classes of subs.

Where is GF when you need him?!

 

[Aussie Digger]

Where is GF when you need him?!

Absolutely flat out with work at the moment. He was in Adelaide last week for the launch of the "Mariner" trial. Don't know where he is now but...

 

[stryker NZ]

ive been wondering this as well it seems both of the new british subs incorporate a more radical design than the Americans. i was just curious as most of the new US ships seem to be way different from previous models bar the Virginia.




(i hope this isnt inappropriate but i would also like to take this time to say Steve Irwin Rest in Peace you were a good bloke and bloody great Australian.

sorry that probably wasnt the right place to put it but i had to say something if an admin wants to remove it i dont mind and im sorry for the trouble.)

 

[arkhan]

(i hope this isnt inappropriate but i would also like to take this time to say Steve Irwin Rest in Peace you were a good bloke and bloody great Australian.

sorry that probably wasnt the right place to put it but i had to say something if an admin wants to remove it i dont mind and im sorry for the trouble.)

i always thought the crocs will kill him someday but a stingray?
animal lovers around the world will mourn his death and watching animal planet channel will never be the same again.
http://www.youtube.com/watch?v=o8h6yXREbV0

 

[Big-E]

I always admired him for his conservation but never did get over his child endangerment. He was too reckless for my taste and his larrikin attitutide (I felt) lowered the sophistication of Aussie's in American minds. The persona that they are crude simple folk was his bread and butter. He just replaced Paul Hogan as what being Aussie means to Yanks. I wouldn't have such a problem with it if Americans could see a counter balance of urban life down-under. ATM this just doesn't exist. He seemed like a great guy however and my prayers go out to his family. R.I.P.

:australia

 

[turin]

As for the Virginia subs: wasnt there some talk on partially revising the design after the first units? This had something to do with the sail being redesigned and looking more like the soviet/russian approach, i.e. lower and roundish. I read about that quiet a while ago and didnt hear anything new since then.

Guess I have to wait for Gary...

@Steve Irwin:
May he rest in peace. At first I couldnt believe it when I saw it on TV. I never thought that the crocs would get him. After all he knew them all his life. So in a tragic way it makes sense that some kind of unusual environment might pose a bigger threat to him taking all these risks.
Also while I didnt like his sometimes crazy and extremely exaggerated style and presentation, I still liked him personally and I watched a lot of behind-the-scenes footage where, I think, one could see the "real" Steve Irwin who was quite different.

 

[Big-E]

@Steve Irwin:
May he rest in peace. At first I couldnt believe it when I saw it on TV. I never thought that the crocs would get him. After all he knew them all his life.

Actually it was a ray

 

[turin]

Actually it was a ray

Yeah I know. Maybe I wasnt quite precise. Someone wrote that he thought, the crocodiles would get him and this always seemed improbably to me because of his experience with them. A stingray makes sense since it was an sort of unusual experience in an unusual environment for Irwin.

 

[Big-E]

Yeah I know. Maybe I wasnt quite precise. Someone wrote that he thought, the crocodiles would get him and this always seemed improbably to me because of his experience with them. A stingray makes sense since it was an sort of unusual experience in an unusual environment for Irwin.

I'm wondering what he was doing to the ray. They are rather hard to provoke, I had to step on one before I got barbed thru the foot. They did video the whole thing... wonder if they'll show it?

 

[Wooki]

As for the Virginia subs: wasnt there some talk on partially revising the design after the first units? This had something to do with the sail being redesigned and looking more like the soviet/russian approach, i.e. lower and roundish. I read about that quiet a while ago and didnt hear anything new since then.

There are designs for the type of sail you suggest. But there are also new technologies being developed (like UUVs and what not). I don't think you'll see a "new" design for a submersible coming out of US yards until certain technologies have matured AND require a new shape.

Its more a question of economics and risk assessment then anything else.

You're best bet on a new shape would be if Navy and Congress decide to go with an ICE/electric, but (just from my observations in talking with people who make these things) it seems to me that there is a decided split within Navy about that.

Cheers

W

 

[enigmaticuk]

I think its great how a thread about subs turned into a RIP to the croc hunter. He was a great bloke though and everyone in the states is shocked as he was such a well liked chap. Maybe now the stingray may be declared one of the most dangerous creatures in the ocean.
Back to the subs it seems like no one has an idea as to the differnece in design of the astute and viginia, the astute and trafalugar looked almost whale like in appearnace so i was thinking it may have been for some kind of stealth purpouses?????

 

[stryker NZ]

As for the Virginia subs: wasnt there some talk on partially revising the design after the first units? This had something to do with the sail being redesigned and looking more like the soviet/russian approach, i.e. lower and roundish. I read about that quiet a while ago and didnt hear anything new since then.

Guess I have to wait for Gary...

@Steve Irwin:
May he rest in peace. At first I couldnt believe it when I saw it on TV. I never thought that the crocs would get him. After all he knew them all his life. So in a tragic way it makes sense that some kind of unusual environment might pose a bigger threat to him taking all these risks.
Also while I didnt like his sometimes crazy and extremely exaggerated style and presentation, I still liked him personally and I watched a lot of behind-the-scenes footage where, I think, one could see the "real" Steve Irwin who was quite different.

i have seen pictures where the virginia class has a more curved conning tower like the russian Akula class subs but i allways thought they were just early prototype designs and had been flagged

 

[powerslavenegi]

mm i DOUBT

the astute and trafalugar looked almost whale like in appearnace so i was thinking it may have been for some kind of stealth purpouses?????

Well I am no sub expert ,but I doubt the way ACTIVE SONAR technology works vis a vis RADAR,the shape of the submarine making much of a difference(in case of a passive Sonar we would have to compare the acoustic sig. of both the subs),however I wonder if it is Hydrodynamically more efficient than the Virginia class(I believe cylindrical and perfectly circular Xsec is the best design for uniformly distributing pressure across the Hull).I would not like to read too much into the hull design until we all get our hands on some declassified info regarding specs like acoustic sig(when moving and idle),maximum diving depth,submerged speed and endurance.Comparasion based on above specs would be fair because both subs are very similar in size and tonnage.

 

[gf0012-aust]

There is an issue of significance to bear in mind with the Astutes vs US subs.

British shipbuilding and expertise has declined significantly over the last few years - to the extent that the USN/NAVSEA was called in to assist the RN in developing and finishing the design of Astute.

The decline has been of such significance that the Sec of Navy (US) was presented with a briefing paper hilighting the flaws and vulnerabilities within US industry so as to reinforce the need to keep persistent and dedicated skills in place. That report also included a strategic overview of UK shipbuilding and tech capability decline vis a vis the Astutes?trafalgers.

UK shipbuilding and engineering expertise is at the very vulnerable end at the moment - and to be blunt, the Astutes would not have been finsihed without US assistance.

Australia has also suffered from the same political influenced demise of strategic building - and we also have ended up having to call in favours from our cousins across the other side of the pacific pond...

 

[powerslavenegi]

Expert

Aha now that GF has returned ,I would like to ask how does pump jet duct propulsion compare with conventional propeller designs(in terms of pure hydrodynamic performance and also any tactical advantage if present).And yes is it true that coning tower of subs are inclined more towards one side to counter the torque induced due to the propeller(if that is the case why dont we use contra-rotating propellers which might perhaps increase speed too).

 

[Big-E]

Australia has also suffered from the same political influenced demise of strategic building - and we also have ended up having to call in favours from our cousins across the other side of the pacific pond...

... which we are happy to provide BTW. I was thinking about our cooperation with the Astutes and remembering the decline of our own sub building programs. The Virginia orders are too few and far between to keep our crews employed long enough to keep the expertise hanging around the yard. That and the political pressure to build them in two different yards only makes it worse. It makes it so expensive for us to build a subs it's really not worth it. The problem for us becomes one of keeping skilled workers at our shipyards. I was wondering, for those that are knowledgable about shipbuilding, would it be a good idea for US shipyards to keep a core crew of highly skilled workers that could tour the globe to our allies' shipyards to teach new generations of workers how to build warships? It seems like we already did that with the Astute project, would it work for everything? That way the US workers could stay employed year round while benefiting allied dometic shipbuilding.

 

[gf0012-aust]

how does pump jet duct propulsion compare with conventional propeller designs(in terms of pure hydrodynamic performance

well. one component doesn't define absolute platform competency - but in general terms. pumps are superior to conventional props

and also any tactical advantage if present).

yes - lots.

And yes is it true that coning tower of subs are inclined more towards one side to counter the torque induced due to the propeller(if that is the case why dont we use contra-rotating propellers which might perhaps increase speed too).

Not all subs are effected by single prop torque issues. -and even then there are other performance envelope issues that have to be factored in.

 

[gf0012-aust]

The Virginia orders are too few and far between to keep our crews employed long enough to keep the expertise hanging around the yard. That and the political pressure to build them in two different yards only makes it worse. It makes it so expensive for us to build a subs it's really not worth it.

The original reason for splitting the builds had some merit - ie load balancing the jobs and risk mitigation issues - as well as spreading the skills base - however the lack of firm orders over a given time frame made the whole baseline model almost unworkable IMO.

The problem for us becomes one of keeping skilled workers at our shipyards.

that was one of the frightening conclusions reached about UK shipbuilding. Its not only an issue of build expertise, but also design capability in specific areas. In some respects the french (for example) have a far more robust and cohesive shipbuilding design and construction capability (at the warship level) than the UK - because their nationalistic pride has encouraged and enforced absolute maint of skillsets.

I was wondering, for those that are knowledgable about shipbuilding, would it be a good idea for US shipyards to keep a core crew of highly skilled workers that could tour the globe to our allies' shipyards to teach new generations of workers how to build warships? It seems like we already did that with the Astute project, would it work for everything? That way the US workers could stay employed year round while benefiting allied dometic shipbuilding.

If the build rates don't go up. then I can't see the big 3 all staying in "the game" - and in real terms its the "'Big 2" as Boeing really are on the periphery.

Construction "tiger teams" would be one way of maintaining capability.

Then again, submerged warfare is about to go through a quantum leap in capability - so the old reference points are not as clearly valid as, say 5 years ago.

The last 18 months have seen some dramatic changes in submerged warfware options. Unlike the sexy stuff like F-22's, they don't get as much media time (which is actually a good thing IMO)

 

[stryker NZ]

i was just reading one of the Janes books and it said that the reason the US stopped the building of the seawolf class was because it was too expensive for a post cold war world right but then it went on to say that the virginia class has ended up costing more is this true or do you think they would be including design costs and stuff like that.