Astute vs Virginia

[Dr.Sid]

Hm .. so once again .. where can I get some info about the new British sub ?

[XabbaRus]

Here are several links

http://www.baesystems.com/newsroom/2...905news181.htm

http://navy-matters.beedall.com/astute.htm

http://www.global-defence.com/2003/astute_03.htm

One thing I like is the shape, the US has stuck with the stretched modified Albacore shape of hull, like a tear drop with the middle cut out and a cylinder put in the middle.

The Astute, like the Trafalgar class and the Vanguard have a more dolphin shaped bow. Any advantage there?

[Dr.Sid]

Great info ! Now I can vote .. I vote for Virginia. It just looks better
Since I'm from Czech Republic, country with no sea and no navy, I have little national preference here

Anyway it seems one of my relatives died on Austrian sub U13 during WWI. War sux .. let's play games instead ..

[Doc Savage]

I thought the Astute's hull looked slightly odd (somewhat fatter) but had put it down to the angle of the photos.
Funny how there are so many different hull designs for subs.
Logically, one would think, a cylindrical hull would be better at distributing pressure evenly over the hull. It might also be easier to build. But apart from the USN, nobody else seems to be making cylindrical hulls.
Some of the ssk hull designs seem to be even more weird. e.g. The Collins, Gotland and the Type 209 (esp. the earlier versions) - wonder what the thinking for those designs was (increased surface range maybe?)

[Bubblehead Nuke]

Originally Posted by Doc Savage

I thought the Astute's hull looked slightly odd (somewhat fatter) but had put it down to the angle of the photos.
Funny how there are so many different hull designs for subs.
Logically, one would think, a cylindrical hull would be better at distributing pressure evenly over the hull.

Don't confuse the shape of the PRESSURE hull with the shape of the outer hull.

You can have a cylindrical pressure hull and the put a rectangular box around it if you want. USN subs do not have an outer hull on them. What you see IS the pressure hull. Many other navies put fairings and such for their own purposes and designs. Ballast tanks, array fairings, the differences in mounting the fairwater planes are all things that can affect the external appearance.

[Lurchi]

Originally Posted by XabbaRus

The Astute, like the Trafalgar class and the Vanguard have a more dolphin shaped bow. Any advantage there?

I believe the difference in the bow form is mainly dictated by different sonar layout concepts. While the US have a bow sonar in form of a sphere the british is positioned around the "chin" of the bow.

The stretched shape with a large cylindrical part of the US boats emphasizes speed and easier series production (especially true for the LA class) while the stout shape of the british submarines offers better maneuverability.

[diver]

Originally Posted by Doc Savage

I thought the Astute's hull looked slightly odd (somewhat fatter) but had put it down to the angle of the photos.
Funny how there are so many different hull designs for subs.
Logically, one would think, a cylindrical hull would be better at distributing pressure evenly over the hull. It might also be easier to build. But apart from the USN, nobody else seems to be making cylindrical hulls.
Some of the ssk hull designs seem to be even more weird. e.g. The Collins, Gotland and the Type 209 (esp. the earlier versions) - wonder what the thinking for those designs was (increased surface range maybe?)

The collins class have cylindrical pressure hulls, however the platform can be seen out of the water is the outer casing which houses all kinds of crap kept elsewhere on USN boats.

If you take a look at a collins (or probably a gotland) out of the water this can be clearly seen.

[XabbaRus]

Like the emergency floatation airbags :rotfl:

[LoBlo]

The cylindrical hulls has less drag, less flow noise, and better sonar-washout speeds, but fitting equipment against a cylindrical surface is a bit more cumbersome iirc.

[XabbaRus]

Uk sub huls are almost cylindrical except for teh bow which seems to be influenced by the shape of a dolphine, I wonder if there is something there too. US hull design seems quite conventional.

[Kapitan]

Th british submarine bows are influenced by the sonar system inside , if you look at the shape it seems that the british boats might have a better bow sonar system than the americans as the shape may give the sonar system a better scope outside.

but hey thats just my radical thinking

[Lurchi]

From a low-drag standpoint a consequent teardrop hull shape is considered as ideal. Two submarine classes which embody this ideal in an almost perfect way are the US Skipjack class and the soviet Alfa class.

However this complicated shape is expensive to manufacture so the US submarines have a compromise in form of a cylindrical middle part. This makes sense because subs like the Sturgeon and Los Angeles were built in large numbers. The hull form of Seawolf and Virginia however becomes more similar to the british design.

[diver]

Originally Posted by XabbaRus

Like the emergency floatation airbags :rotfl:

Enough of that, they aren't Russian.

[XabbaRus]

Ooh a little touchy are we...

[Kapitan]

As it goes floatation airbags are a russian idea implemented in the november and hotel class submarines then later on they were implemented on the akula and kilo's typhoons oscars the works, that big red and white signal bouy is a floatation device and oddly enough it happens to be attached to russian submarine.

So yes xabbarus is quite right there.