Smaller SSNs and even SSKs for U.S Navy starting next decade

Funding curb forces Virginia reality check

By Andrew Koch JDW Bureau Chief
Washington, DC
Janes


The long-term health of the US Navy's Virginia-class nuclear-powered attack submarine (SSN) - one of its most cherished programmes - appears in grave danger because of the growing cost of the war in Iraq, tightening defence budgets and mounting deficits.

According to US Department of Defense (DoD) documents, statements by senior navy officials and insider accounts, a combination of funding shortfalls and pressures from the highest levels of the DoD are moving decision-makers toward the conclusion that the Virginia-class programme should be cancelled well before its planned 30 boats will be built.

One well-placed source told JDW the navy could build as few as 10 of the boats before switching to a new design in about 2012. The service had planned to move to a substantially modified centre section design of the Virginia at about that time, which would allow far greater flexibility in the types of payload carried such as unmanned vehicles and weapons. If the new plan continues, the source said, the navy could start buying a new smaller SSN, possibly augmented by diesel-electric attack submarines (SSKs) with advanced air-independent propulsion (AIP). US Deputy Secretary of Defense Paul Wolfowitz, the source said, recently visited Germany to inquire about gaining access to AIP boats, although JDW was unable to verify this before going to press.

In a directive issued at the end of December 2004, Wolfowitz directed the navy to "design a future undersea superiority system alternative ... that includes considerations of new propulsion systems" and applied $600 million to the effort over the next six years. The navy has been working on a design that uses distributed pump water-jet propulsion for the past year and the source said "those involved say its going to be amazing". The same directive - Program Budget Decision 753 - also removed funds for three Virginia-class boats, keeping production rates at one per year rather than two starting in Fiscal Year 2009 as previously planned.


I really like that part about water-jet propulsion.

[edit on 14-3-2005 by NWguy83]

There are already AIP systems on the drawing board that would provide 3+months operation without surfacing. So big expensive nuclear subs may soon be a thing of the past.

Good article from NavyLeague.org

I can see how they would be smaller seeing that there going to have weapon bays instead of torpedo tubes. Which will make the design altogether smaller.

I like the water jet propulsion but I don't like having no Nuclear subs, the report doesn't say that but still I think it should be a mix rather than all diesel and other propulsion systems and no nuclear.

Originally posted by WestPoint23
I like the water jet propulsion but I don't like having no Nuclear subs, the report doesn't say that but still I think it should be a mix rather than all diesel and other propulsion systems and no nuclear.

Why would anyone put a waterjet on a sub? far too noisy and inefficient. They are looking into alternatives in part because their big nuclers boats are designed for blue sea's work and and not as good at littoral warfare. The smaller AIP and DE boats have always been better here.

Sub warfare is going to radically change over the next 10-20 years like never before.

Don't know about the water jet they must have figured out away to eliminate the bubbles or something. And Sub warfare will change in the next 10-20 years because not a lot of country's have blue water capability. However China is ever developing and when they do have the capability and pose a threat then it would be a pain in the A to convert back dont you think?

Originally posted by WestPoint23
Don't know about the water jet they must have figured out away to eliminate the bubbles or something. And Sub warfare will change in the next 10-20 years because not a lot of country's have blue water capability. However China is ever developing and when they do have the capability and pose a threat then it would be a pain in the A to convert back dont you think?

Water jets get their advantage by ejecting the water into a less dense medium (dont need to waste as much energy pushing the less dense air out of the way) so are of very lttle use below the surface.

Nobody has suggested the the US should completly lose their blue water capablility, that would be insane. they are however in the process of adding some more brown water capability to the mix. The design of subs is moving away from a platform based design to a more capability driven design process and with modern design and construction techniques the traditional designs are by no means the only options (is the sausauge and fin design really the best?). There are some really radical designs for submarines in development at the moment.

[edit on 5-4-2005 by paperplane_uk]

water jet? you mean pump jet propulsion based on UK design first put on Seawolf class sub in U.S. navy, i dont support electric diesel subs since they still have limitations, no matter how expensive nuke subs are they are still worth taxpayers money its just accounting problems the reason for the expensive subs.

Yes he could be mistaken and taken a pumpjet to mean a waterjet (massive difference), but i was just clarifying why a waterjet would not be used. pumpjets were first in operational service with the second of the RN's Trafalger class (Trafalger herself started with a standard prop) in the early 80's. They are much quieter than normal propellers and so have been adopted for the standard propulsion system of new classes in most western navies (certainly UK, US and Austrailia, probably france too).


DE subs are slowly coming of age, with modern developments in AIP systems, fuelcells and batteries, it is technically achieveable to design DE subs that dont have to snorkal very often. They are well renowned for being the best option in coastal waters that are often too shallow for a nuclear boat to work in effectively, so i would not be suprised to see small numbers of them sneaking into the western navies over the next few years to supplement the nuclear boats.

its better to have a ceramic nuke sub capable of 16,000 ft depth. kinda like the book by Joe Buff (Deep Sound Channel) the american sub U.S.S. Challenger sub. awesome book also you should read the rest of his books.

I hope the germans dont sell it to the americans, I dont want this exploitation of german know how, like it happend the last century

Originally posted by Wodan
I hope the germans dont sell it to the americans, I dont want this exploitation of german know how, like it happend the last century

I don't think it is too difficult to make AIP (at least for US) just replace reactor with fuel cells and make smaller sub. US Navy already has much larger experiences with propelers, quitening, sensors etc.

BTW I heard new nuclear subs do not use pumps at all when moving low speed l (Ohio SSBMs certainly, Seawolf and Virginia= high probabillity) - it is called natural circulation, so AIP/diesels would loose it's main advantage - almost no sound at 4knots.

All they have to do is at least keep 70% of the Sub fleet at nuclear powered. And the other30% equip it with diesel or whatever suits the needs of costal operations. But to have very little nuclear subs left and the majority being diesel is insanity to me.

Conventional subs for the US Navy do not make much sense, unless you are prepared to permanently base them at overseas locations. Their lack of speed an endurance makes repeated crossing of the Atlantic and Pacific somewhat problematic.

Although conventional submarines are very quiet, they lack the ability to "sprint" when necessary, especially during combat operations when high-speed maneuvers may be required. When a conventional sub "shoots", they cannot "scoot", and if there is any counterfire, that sub is going to have to deal with torpedos aimed at it.

Nukes also have another really important advantage - unlimited electricty. Which drives things like air scrubbers, desalinization plants, ROVs, surveillance equipment, etc.

The US Navy essentially sees SSNs as an offensive weapon system, where most other countries use them defensively. As long as we have to drive across the pond to start a rumble with other navies, the SSN will always be the weapon of choice.

Although conventional submarines are very quiet, they lack the ability to "sprint" when necessary, especially during combat operations when high-speed maneuvers may be required. When a conventional sub "shoots", they cannot "scoot", and if there is any counterfire, that sub is going to have to deal with torpedos aimed at it.

thats the reason the hydrogenium cell driven U212's are stealthy

Like any tall tale, the capabilities of the U212 seem far-fetched. For starters, it is capable of being underwater for up to three consecutive weeks -- THREE WEEKS! You try holding your breathe that long!



The secret behind the U212's underwater endurance lies in its air-independent propulsion (AIP) system. Developed by Howaldtswerke-Deutsche Werft GmbH (HDW), the U212's AIP system uses a silently operating fuel cell plant. The plant, running on nine 34-kilowatt Siemens polymer electrolyte membrane (PEM) hydrogen fuel cells , allows the submarine to remain submerged for weeks at a time without surfacing, ideal for extended underwater/ low speed operations. Without a need to snorkel, the AIP system also allows the U212 to operate silently without emitting exhaust heat, reducing detection.

The U212 also uses a state-of-the-art sensory system (As good ol' granny would say, "To better hear you with."). An integrated DBQS-40 sonar system aboard incorporates the following: a cylindrical array for passive medium-frequency detection; a TAS-3 low-frequency towed array sonar; a FAS-3 flank array sonar for low/medium frequency detection; a passive ranging sonar; a hostile sonar intercept system; and, an active high-frequency mine detection sonar - the STN Atlas Elektronik MOA 3070.

So, it can pounce like a wolf and hear like a wolf, but how strong is its bite?

Much like a wild animal, you wouldn't want to anger a U212. Besides carrying up to 24 sea mines externally, the submarine is armed with the DM2A4 torpedo from STN Atlas Elektronik. The DM2A4 -- aka Seahake Mod 4 -- is an electrically-driven torpedo that has a range of more than 27 nautical miles (50km) and a speed of approximately 50 kts. The DM2A4 uses new, conformal acquisition sonar, featuring 38 staves (152 transducers), which produce pre-formed, wide-angle beams. In addition, the Seahake utilizes a 250kg hexagon/RDT/aluminum high-explosive warhead (equivalent to 460kg of TNT) with magnetic influence and contact fuzes, as well as a wake sensor to improve torpedo counter-countermeasures capabilities.

Additionally, the U212's torpedo launchers have something most other submarines do not have -- a water ram expulsion system. Don't you wish you had one? Whereas the 688 Los Angeles class launches torpedoes using "noisy" compressed air, the Type 212's water ram expulsion system ejects the torpedo from the tube without the launch "transient" associated with using compressed air. In other words, the 212 can fire torpedoes stealthily, reducing the possibility for a counter attack. (Can you hear the high praises of its 27-man crew, including the U212's 5 officers?)

To further protect itself, the U212 employs the TAU 2000 torpedo system. Used as a countermeasure, the TAU 2000 has four launch containers, each with up to ten discharge tubes equipped with effectors. Effectors are small underwater vehicles similar in appearance to a torpedo that act as decoys or jammers. When deployed in multiple numbers, effectors use hydrophones and acoustic emitters to counter torpedoes in re-attack mode. (The crew is on its feet!)

... www.military.com...

Originally posted by WestPoint23
But to have very little nuclear subs left and the majority being diesel is insanity to me.

Nobody on here has suggested they do anything of the sort.


There have been a number of designs proposed that involved having 2 small desiel electrics attached to a large nuclear boat. They hitch a lift on the nuke across the oceans, before detaching to go close inshore for intel gathering/ spec ops insertion etc. meanwhile the big nuke hangs around offshore to resupply and back up the DE boats. It all depends if the docking mechanism could be worked out correctly (think space shuttle docking at the ISS rather than a landing ship type dock).

It is called the SMX-22
euronaval2004.dcn.fr...
www.dcn.fr...='barracuda%20submarine%20concept%20design'




[edit on 6-4-2005 by paperplane_uk]