Okay color me stupid, but arn't all modern subs double hulled? I mean there is the inner pressure hull here the crew lives then the outer hull which is used to contain all the parts open to the sea. The outer hull has the balest tanks the sonar the shaft for the propeller the conning tower and the shafts of the torpedo tubes.
When speaking of double hulled boats, they are speaking of two pressure hulls.
Most all subs also have an outer hull that is not meant to be a pressure hull. The US builds a single pressure hull, using very high grade steel. The Russians and some others buold double hulls.
Even then, U.S. submarines do not have an outer hull around the entire boat. Normally the outer hull ais t the fore and aft and contains the ballast tanks.
As for why we build them without two pressure hulls...here are some thoughts.
The Russians subs were not very quiet...they expected that they would be found and they wanted to make them as survivable as possible. And against light weight topredoes, this would probably work for a time, it taking mulitple hits to sink them. But enven one good hit is going to make them even louder...and noise like that will mean a lot more torpedoes will be coming.
But...against an Mk-48 heavy weight, particularly the ADCAP version, double hulls would not save it.
The US was typically orders of magnitude quieter and did not ecxpect to be found. A submarines real survivability is dependant on its stealth and the US has sunk most of its R&D into that.
The double pressure hulls are very expensive, and they are a lot heavier. Weight requoires more power too. Russian subs are almost as expensive as US subs, but the money is generally spent in different ways. As the Russians have developed better quieting and electronics, their costs have risen accordingly.
Now lets talk about maintenance.
Two pressure hulls are more expensive to maintain. The more time a boat is at sea the more maintenance you have to do in port. Most submariners will work 100+ hours a week while in port on duty taking care of all the maintenance and training that happens in port. US Submariners many times get more sleep on patrol than at at home.
Add a second pressure hull and you increase the cost and time for maintenance...which invariably means less time at sea. Check out the deploymehnt schedules for US vs Russian and many other submarines.
Finally, lets talk consistancy. The US intends to build one design repeatedly ...ver and over. TThe Sea Wolf was not that way...but the LA Class certainly was, and the Virginia class will be too.
TheUSSR built a new class of subs every time someone had a new idea. We will see if the Russians can afford to continue that. My guess is, their numbers are going to be sparing when compared.
Two or three boats per class means huge logistical issues and a lot more training and maintenance. This is a huge advantage for the US in training and logistics. Rusian boats required many more custom parts for each boat, which meant customized training and operations. But an engineering sumbmariner that can start up the engineering plant on one LA Class boat, is going to be able to do the same on any of the dozens and dozens fo LA Class boats out there.
The US reactors are top notch and also built in large batches. The Russians and othewrs? Not so lucky. The USSR and Russia used diesels, pressurized water reactors, liquid metal reactors, sodium cooled reactors, etc. A logistics nightmare...and many of those designs, like the ALphas, were death traps from a radiation standpoint.
Now, we can come to the materials used in those hulls. The USSR and later now the Russians control a majority of the world’s titanium supply. Titanium is strong, so it can dive deeper...but it is also brittle and they were very expensive. That's not a good combination for submarine building, maintenance, and operation.
IMHO, the advantages of double hulls for the Russians and others do not outweigh the disadvantages...unless they can catch up with and pass the US/West in several areas:
1) Their quieting technology.
2) Their maintenance costs.
3) Their weapons capabilities.
On number 3. A lot is said about the Russian deployment of their super cavitiating torpedo. Yes...it is fast. but its has a very short range. That's why in my book series where supercavitatig torpedoes were an important part...the torpedoes were huge. Miniature subs themselves with dual proplusion...so they would have a decent range. And their closing sprint speed under supercavitation was like 400+ knots...not the much slower speed of the Russian weapon.
I personally would rather be in a US SSN, which is very, very quiet, and holding a brace of Mk-48 ADCAP torpedoes with a range of 45,000+ yards, and a closing speed in exccess of 50 knots, than on any Russian sub with one of their very dangerous supercavitators with a range of 7,500 yards.
Anyhow...sorry for the length...but you got me noodling the topic!
