I would say, with my rudimentary knowledge of physics that the bigger the boat the greater the flow noise at speed. Of course, the shape of the front can help a bit, but if you make it too sharp then you run the risk of cavitation and loss of stability IIRC.

The Oscars are good boats, built primarily to knock out US carrier fleets by spamming ASMs. They're an ASuW boat for certain, not an ASW, but as Kap says, that's not to say they don't have teeth, but I'd much rather tangle with an Oscar than a late model Akula. :yep:

That would depend on the situation at hand to some extent which one is more dangerous but to a surface vessel the Oscar is much more dangerous than an Akula when you take into consideration the stand off range of its cruise missiles the Oscar makes a very good area denial weapon system.

D'oh! That's what I get for typing whilst tired, I meant to say in a Submarine that I'd prefer to take on an Oscar II rather than a Akula II. Providing, of course, that he didn't get a good enough bead on me that he lobs a Skhval at me...hate those things, ruin a good day very quickly. :yep:

Some time ago i was reading a report on hydrodynamics written by an australian author its around on te forums some where, it gives a good insight into the way water flow causes noise ballasting and also properties
ect.

if you look at U.S U.K france germany and new models from russia the big wide boats have been laregly replaced, i personally think the USN got it right with dimensions of thier attack submarines being a more sausage shape, if you look at the typhoon and oscar II they are more wedge shape which on the surface causes a large under current around the sides, and submerged the water has to flow over a much larger surface area and indeed has the potential to create even more noise, its not going to just be the mechanics of the submarine that gives it away but water flow also.

you need to bear in mind that Oscar II's are 24,000 ton displacement boats they are slow to respond to quick direction and speed changes.
Most of the problem is size for them, hence why russia has now realised acctually the american system works and i have to praise the USN in that they created an entire attack fleet made of small SSGN's although you class them as SSN's.
688i and virginia are very good designed boats they have the qualities of a normal SSN but are so versatile that you only need one class of submarine in service which in turn cuts cost, the russians went about creating around 40 diffrent classes of submarines where the americans used only 2 classes, the whole VLS thing is a good idea.

HOWEVER!

The russian SS-N-19 missile is a great deal larger than any missile in the US or UK force infact its around 7tons in wieght compaired to the harpoon which is what 1.5 ton? this limits the number of units capible of carrying this missile (only the oscar kirov and Kuznetsov can carry them) because of thier size, the missile range is far beyond that of the harpoon and not only that it travels far faster mach 2.5 with a range of 550km-650km one of these is enough to mission kill a carrier and the oscar houses 24 of them.
The SS-N-19 is much a sea skimming missile it is fire and forget it can use AWACS to locate its target or Satalite and once fired one missile climbs to 20,000ft and acts as guide feeding information to the other missiles and if thats engauged another takes its place.
The russians would volley fire these missiles and they are not worried if 20 get shot down as long as one gets through to a carrier it basically puts you out of buisness.

Oscar II's are not like typhoons, they are double hulled and have a 32% reserve boyancy compaired to around 15% in UK and US submarines roughly ish dont quote me.
This means that with 2 of 9 compartments flooded she can come to the surface and the reason the kursk didnt is just because of the sheer damage to everything when she blew up thats before you ask.
Oscars are designed to take atleast one direct hit and carry on, they were never designed to come face to face with enemy submarines but maintain a weapons arsenal of 24 torpedos in which some may be skhval, (BTW an oscar probably would only carry 2 or 3 of these not an entire load)

Oscar was built in the early 1980's with murmansk and arkangelsk being the two lead Oscar I boats these were withdrawn in the late 1990's and only the 13 remaining Oscar II's were still active all were built between 1983 and 1998 with belogorad still unfinnished come 1999, what we now see is remarkable.

Instead of building on the same scale they have slimmed down the yasen is much smaller but carries smaller missiles but still has the same qualities as the Oscar II, far quieter more agile and more capible at ASW this is more like the Russian 688i.

the entire point of having a large submarine was to boats about it most of the russian fleet is to say to the USN mine is bigger than yours, take the Kirov for example the USN re-activated WW2 battleships just so they had something to combat it as the tico's were smaller and not as well armed as a kirov on paper, but they remain the largest cruisers that have put to sea and at 33,000 tons you can see why they are by far heavier than some countries aircraft carriers and larger in length too.

Big doesnt always mean better against a carrier group 4 Oscar II's could reek havoc easily but they would fall victim to american submarines later on where as the akula could deal with the submarines but would struggle against the aircraft carrier as the missiles it carries are easily tracked and shot down so it would need to torpedo the carrier which means running a gauntlet with very little chance.

Which brings you to the reason why the russians use the bastion concept a dedicated ASW unit such as the akula victor III Sierra's etc would protect oscars from enemy submarines while they protect the SSN from surface units again this works in theory with surface units, the sovremenny would normally be paired with an udaloy one to do ASW the other ASUW AAW/ its the same in the USN where a burke would be paired with a perry and the UK a type 42 or 45 with a type 22 or 23 double layered protection.

But in a knife fight the akula carries more weapons and more tubes and can reload faster than most american submarines it can have more weapoins in the water at any time than any other western submarine so it is a formidable platform and so is the oscar II even against submarines it does carry 8 tubes with 24 reloads.

On the topic (terribly sorry for the necro)
- Oscar IIs are to be refitted with Yahont/Kalibr launchers (3 Yahonts or 4 Kalibrs per the old Granit tube I believe).
- Yasen has 8 large silos behind the sail with 24 Yahonts or 32 Kalibrs between them.

Ie while Yasen remains a fairly competetive attack sub, the Oscar IIs refit appears to be more in line with the missile truck (72-96 weapons I think) concept.

So, really you can compare the Yasen with a flight II Los Angeles in that it possesses an array of vertical launch tubes but is not solely dedicated to ASuW warfare unlike the Oscar II which is definitely geared towards hitting surface vessels, with the ASW armament for primarily defensive and back-up methods.