Needs to be pointed out thst the Seawolves were expect to go out with the tube launch Tomahawk and Harpoons. And still do as far as I know.
As were their previous designs after the Tomahawk came out then before that there were the special sub only weapons like UGM-89 Perseus STAM. So it is a strange thing that the Seawolf lacked VLs.
The US been trying to have a big deep diving attack sub with a metric asston of tubes since at least the early 1970s as seen by the Advanced Performance High-speed Nuclear Attack Submarine (APHNAS) concept of 1970 to 74.
Likely be seeing a similar design set up for tge SSN[x] before its pruned downed for budget.
Sure, but even sending them out with a dozen Tomahawks for tube launch gives them 14 more weapons than a 688i. I'm going to ignore Sub-Harpoons because the 688s also had to carry them in place of torpedoes, making it a wash.
The fine art of submarine torpedo loadouts is always a case of "not enough (all the expletives deleted) room!!!"
So I suspect that the Navy's wish-list is going to be about 24x VLS and 50x torpedo room stows with 8x torpedo tubes. A Seawolf forward compartment with a quad pack of VPMs. I'd go so far as to assume larger diameter and longer torpedo tubes than currently used, to give space for bigger torpedoes or other things to be shoved out a torpedo tube. 65cm ish tubes, again like the Seawolves. And if they don't make bigger torpedoes? Sleeve the tubes down to 21", no real loss.
Early on, I was contemplating an absolutely huge ocean access using a Trident tube laid horizontal, to give access to UUVs that aren't 21" diameter. 85" inside diameter or so. But that would make a very noisy hole in the hull, and would have a lot of excess pressure if the boat is making any way forward at all. Better to point UUV accesses aft, either in the engineroom or some weird midships thing like SSN23 has. If there's no shaft going through the pressure hull, there's room to put UUV hangars in the engineroom.
Amazing. A fallacious and ignorant statement followed by an arrogant and ignorant statement. You need to check your ego and grow up.
If your weapons can't reach me (which in the case of K-278, they can't) then I don't need to hide and I can pound your ass with active sonar and kill you. Maybe you're angry because you can't reconcile the fact that current US submarines with their single hull construction, almost non-existent reserve buoyancy, lack of any sort of escape system and shallow diving depth are among the most dangerous boats in the world to be on. I know many in the Navy who agree that relying solely on stealth is a recipe for disaster. The only weapon US submarines have is stealth.
Amazing. A fallacious and ignorant statement followed by an arrogant and ignorant statement. You need to check your ego and grow up.
If your weapons can't reach me (which in the case of K-278, they can't) then I don't need to hide and I can pound your ass with active sonar and kill you. Maybe you're angry because you can't reconcile the fact that current US submarines with their single hull construction, almost non-existent reserve buoyancy, lack of any sort of escape system and shallow diving depth are among the most dangerous boats in the world to be on. I know many in the Navy who agree that relying solely on stealth is a recipe for disaster. The only weapon US submarines have is stealth.
Explain to me how diving depth is useful to a submarine, when everything it wants to kill is either on the surface or trying to kill things on the surface.
-A submarine with a K-278 (3350' test, 4250' max safe) or greater depth capability can maneuver in a true 3-D environment, whereas most SSN's can only usefully dive to a depth equal to approximately 4 times their own length, which is a particular limitation when operating at high speeds.
-Ability to stay well below the effective depth capability of any existing weapon, rendering it invulnerable and requiring -at a minimum- development of a totally new class of torpedo- assuming the test/DNE depths are even known. (The assumption would be that the deep diving sub has weapons that can be launched at its own max depth)
-The average depth of the worlds oceans is approximately 12,500 feet. Current subs utilize only a fraction of the ocean's useable volume.
-A submarine built to withstand deeper depths will be far more survivable against underwater explosions, collisions, etc.
-Deep diving has its own stealth advantages, such as reduced cavitation with increasing depth and enabling use of the deep sound channel as a detection barrier. Also, there are consequently far more locations where resting/hovering on the seafloor is an option and utilizing terrain masking.
-Immediately prior to the post-cold war brown water/littoral obsession, the US (and Russians) were specifically looking at SSN's with test depths in the range of 4000-7000 ft, along with other technologies that had been investigated for some time, such as boundary layer drag reduction techniques (polymer, gas injection), retractable sails, single-shot weapons tubes located outside the pressure hull, etc.
-An SSN like this would of course be more optimized for sub-to-sub or anti-surface ship combat and not for launching cruise missiles.
K-278, the prototype Soviet 4th gen submarine and the only one of its class and sank due to a fire killing 2/3rds of her crew on her very first patrol?
Theres a reason the mass production 4th gen versions had only half (Akula) and a third (Yasen) of her crush depth capability, firstly building a large submarine out of Titanium is very expensive and while the USSR could afford to do it for submarines only displacing a couple of thousand tons when it came to the 8,000 ton Akula it just wasnt viable. Secondly after the K-278 was launched within two years NATO countries rapidly developed and fielded deep diving torpedoes that were fast enough to outrun her (Mk 45 Adcap in 1985 and pre-series Spearfish) so the advantage of sailing underneath the opponents weapons was lost.
I'd add that double hulls don't seem to have any advantage over single hulls, either in diving depth or acoustic signature (there can be resonance problems between the outer and inner hull).
Britain planned to have very deep diving depths (circa 4000 feet) for SSN0Z, to take advantage of sonar ducting and reliable acoustic path. These depths would be achieved through a thicker relatively conventional steel pressure hull.
They had no intention of skimping on silencing though.
-A submarine with a K-278 (3350' test, 4250' max safe) or greater depth capability can maneuver in a true 3-D environment, whereas most SSN's can only usefully dive to a depth equal to approximately 4 times their own length, which is a particular limitation when operating at high speeds.
Not that bad a limitation. Most subs have their "best speed" depth at more like 700ft. Any shallower and they're going to risk broaching in the event of the stern planes jammed in full rise. Any deeper and they risk significantly exceeding test depth in the event of the stern planes jammed full dive.
-Ability to stay well below the effective depth capability of any existing weapon, rendering it invulnerable and requiring -at a minimum- development of a totally new class of torpedo- assuming the test/DNE depths are even known. (The assumption would be that the deep diving sub has weapons that can be launched at its own max depth)
Everything subs hunt is within about 1000ft of the surface, and the overwhelming supermajority of what subs hunt is on the surface.
Even if you're hunting another sub, they're probably within 400ft of the surface and likely shallower than that because their targets are all shallow or on the surface.
Granted. But 4" or so of HY80 seems to be adequate, even if you end up running into a seamount at 35knots. Doubling the hull thickness means that you are adding a lot of weight, and that kills your reserve buoyancy.
-Deep diving has its own stealth advantages, such as reduced cavitation with increasing depth and enabling use of the deep sound channel as a detection barrier. Also, there are consequently far more locations where resting/hovering on the seafloor is an option and utilizing terrain masking.
You only need to get down to about 750m/2500ft for the minimum sound speed in water, so I wouldn't push for more than 3000ft test depth.
Or, you install a VDS system in the sub and let the sonar fly down that deep while the sub stays in shallower water. And the VDS would be a lot cheaper than building a sub for 3000ft test depth.
-Immediately prior to the post-cold war brown water/littoral obsession, the US (and Russians) were specifically looking at SSN's with test depths in the range of 4000-7000 ft, along with other technologies that had been investigated for some time, such as boundary layer drag reduction techniques (polymer, gas injection), retractable sails, single-shot weapons tubes located outside the pressure hull, etc.
And yet the Seawolf class does not have a test depth in that range. Doesn't have boundary layer systems. Doesn't have retractable sail. Doesn't have single shot external tubes. (Neither does Virginia, but Virginia was an economy boat. Seawolf was the "no expenses spared" version.)
Which still runs into the problem that all the things that it's hunting won't be that deep. They'll be up on the surface, or maybe 1500ft down at most.
There's no reason for you to go 5000ft down and be on the wrong side of a whole stack of thermoclines when your targets are on the surface. You need to be shallow to hunt surface ships, and honestly less than about 200ft so you can hear them.
There's no reason for you to go 5000ft down and be on the wrong side of a whole stack of thermoclines when your targets are on the surface. You need to be shallow to hunt surface ships, and honestly less than about 200ft so you can hear them.
At 5000 feet theres over a literal ton of pressure, bout 2100 psi, on the sub.
Unless you only want bout 6 shots by extra tubes, you going have to ensure the torp tudes can take that. Cause any leaks on the inner door is going to be outright impossible to patch unless you surface.
Thats with the sub standing still, any forward movement is going to increase that pressure significantly.
A whole lot of pain for not much worth.
But being that deep would be useful for the Sprint potion of Sprint in Drift, and for escaping. But unlikely useful for attacking.
And let's note that the K-278 (Mike for folks familiar with the NATO designations) only lasted a few years before she caught on fire and sank in the Norwegian Sea with great loss of life. The Russian Navy has not replicated that experiment and their current production subs are much more in line with other nuke sub operators.
And let's note that the K-278 (Mike for folks familiar with the NATO designations) only lasted a few years before she caught on fire and sank in the Norwegian Sea with great loss of life. The Russian Navy has not replicated that experiment and their current production subs are much more in line with other nuke sub operators.
SSN(X) now been pushed back to the early 2040's, in every year for the last 3 years its schedule has been put back by 3 years such that its gone from a 2031 first launch scheduled in 2021 to an early 2040's target this year!
SSN(X) now been pushed back to the early 2040's, in every year for the last 3 years its schedule has been put back by 3 years such that its gone from a 2031 first launch scheduled in 2021 to an early 2040's target this year!
-Deep diving has its own stealth advantages, such as reduced cavitation with increasing depth and enabling use of the deep sound channel as a detection barrier. Also, there are consequently far more locations where resting/hovering on the seafloor is an option and utilizing terrain masking.
1) nuclear subs require special preparation to rest on the sea floor. Need landing skids or wheels to keep from plugging the main condensers with mud.
Which is why there is a very short list of nuclear subs that are intended to park on the sea floor. Halibut, NR-1, Parche, Jimmy Carter, and whatever boat replaces Carter in the 2030s. Maybe an equal number of Russian boats. The Brits have never admitted to pulling off any cable tapping operations via subs, probably because the necessary landing gear compromises other missions and basic stealth.
2) the continental shelves go down to about 600ft and then the bottom drops out to over 8500ft. If you're in the Pacific Ocean, the 100 Fathom line (marking 600ft of water) is roughly 1 mile from the shore of any volcanic island. 2 miles off Waikiki Beach, the ocean is over 1200ft deep.
The Brits have never admitted to pulling off any cable tapping operations via subs, probably because the necessary landing gear compromises other missions and basic stealth.
TBF, the UK is barely willing to admit to having submarines, much less comment on what they might or might not get up to.
As far as bottom sitting goes - 2,000 feet lets you go virtually anywhere on the continental shelf. 20,000 feet lets you go virtually anywhere in the ocean. There's not a lot of benefit in between those two points.
4000 feet lets you take advantage of various underwater acoustic phenomena, hence why SSN0Z was supposed to be capable of diving that deep. It was however a relatively conventional steel-hulled submarine, with the usual emphasis on silencing, and not an Alfa-esque fast, noisy submarine.
Is it even worth trying to dive that deep? From what I understand, the Taiwan Strait and South China Sea are all relatively shallow.
Other thing to consider is material type.
Should also preface this by saying I have no idea how accurate these numbers are.
From what I recall, the deepest diving HY-80-based submarines were the Permit/Thresher-class and the Sturgeons, and those had a test depth of 1320 feet. Those also had a smaller surface area that succeeding submarines, as reactor sizes grew.
The Seawolfs where supposed to be built with HY-130 steel, but the shipyards couldn’t work with that strong a material so they went down to HY-100, which was also a nightmare to use. From what I recall, Seawolf test depth is 1600 feet.
Is it even worth trying to dive that deep? From what I understand, the Taiwan Strait and South China Sea are all relatively shallow.
Other thing to consider is material type.
Should also preface this by saying I have no idea how accurate these numbers are.
From what I recall, the deepest diving HY-80-based submarines were the Permit/Thresher-class and the Sturgeons, and those had a test depth of 1320 feet. Those also had a smaller surface area that succeeding submarines, as reactor sizes grew.
The Seawolfs where supposed to be built with HY-130 steel, but the shipyards couldn’t work with that strong a material so they went down to HY-100, which was also a nightmare to use. From what I recall, Seawolf test depth is 1600 feet.
"The “HY” steels are designed to possess a high yield strength (strength in resisting permanent plastic deformation). HY-130 yield strength in ksi is 130,000 psi. HY-130 is generally considered unweldable. Available to the MIL-S-24371 which has now been superseded by NAVSEA Technical Publication T9074-BD-GIB-010/0300."
From what I recall, the deepest diving HY-80-based submarines were the Permit/Thresher-class and the Sturgeons, and those had a test depth of 1320 feet. Those also had a smaller surface area that succeeding submarines, as reactor sizes grew.
Not entirely correct; NR-1 and DOLPHIN both had HY-80 hulls and a reported 3,000 foot test depth. The steel used in the original bathyscaphe pressure hulls also wasn't much different in properties than HY-80 - though in that case, the pressure hull was relieved of the requirement to be buoyant.
FWIW, HY-130 was originally specified as HY-140, but the strength couldn't be maintained when welded. A yield strength of 150 ksi was the ultimate target. Depending on which deep-submergence project you're looking at, you can see references to all three strengths (or even HY 130/150), but it's the same material. For really extreme uses, HY 180/210 was being developed.
It's interesting that aluminium never really comes up in these discussions. It's a surprisingly good pressure hull material - not especially strong, but very light, so performs similarly to titanium,
The Navy moved its SSN(X) from a 2035 start to the "early 2040s," as it takes risk in modernization programs to pay for current operations and readiness.
It's interesting that aluminium never really comes up in these discussions. It's a surprisingly good pressure hull material - not especially strong, but very light, so performs similarly to titanium,
My understanding was that while Aluminium got stronger in cold temperatures it became less ductile and while that may be okay for a ship in icy waters, in a submarine you want a bit of pliability to absorb the pressure without shattering.
My understanding was that while Aluminium got stronger in cold temperatures it became less ductile and while that may be okay for a ship in icy waters, in a submarine you want a bit of pliability to absorb the pressure without shattering.
As far as I know no aluminium submarine has been built since the Aluminaut (1966-1970) which was built by the Reynolds Aluminium Company for promotional purposes. The submarine she rescued in 1968 on the other hand, the DSV Alvin, is still in service 60 years later.
SCS averages something like 2000ft deep, and has a lot of seamounts in it to mess with the average depth. Has places that are probably 8500ft deep and also has shoals that are 10ft deep.
As far as I know no aluminium submarine has been built since the Aluminaut (1966-1970) which was built by the Reynolds Aluminium Company for promotional purposes. The submarine she rescued in 1968 on the other hand, the DSV Alvin, is still in service 60 years later.
4000 feet lets you take advantage of various underwater acoustic phenomena, hence why SSN0Z was supposed to be capable of diving that deep. It was however a relatively conventional steel-hulled submarine, with the usual emphasis on silencing, and not an Alfa-esque fast, noisy submarine.
2500ft or so gets you down to the lowest sound speed in water, so there's not much reason to have a test depth below 3000ft (with an implied design crush depth of ~4500ft). Still means a hull ... let's call it on the order of 3x thicker than what is currently in use, and that's battleship armor plate thicknesses. How much is that going to weigh?
So I'd still just as soon install a variable depth sonar and let that do the deep diving while the sub cruises around above 700ft.
The Navy moved its SSN(X) from a 2035 start to the "early 2040s," as it takes risk in modernization programs to pay for current operations and readiness.
Not DOA, the USN still needs a newer base design than the Virginia class (which I will remind you is almost 30 years old now!).
It's just that the USN is kinda stuck with needing to replace a lot of their ships in the same rough timeframe. It's a sad leftover from WW2. Built a crapton of ships for that, they all timed out in the 1960s, their replacements all timed out in the 1980s, those replacements started timing out in the 2010s (longer ship life).
2500ft or so gets you down to the lowest sound speed in water, so there's not much reason to have a test depth below 3000ft (with an implied design crush depth of ~4500ft). Still means a hull ... let's call it on the order of 3x thicker than what is currently in use, and that's battleship armor plate thicknesses. How much is that going to weigh?
4,000 feet does get you down into the SOFAR channel in most of the world, if you wanted to do that. With Royal Navy design philosophy, and a 33 foot hull diameter, that means a design collapse depth of 7,000 feet.
Basic hoop stress equations give you a required plate thickness of 157mm. That's going to be pretty darn heavy, but is a long way from battleship armour. Admittedly that's a very simplified approach - I don't do submarine structures, and I'm intentionally not asking the people who do.
That is pretty close, and more then basically any cruiser type besides the Alaskas had.
As is that going to push the Sub weight well over the 10k ton mark with NO KIT before adding it the tanks.
That is not going to be cheap either...
When you factor in all that? It honestly not worth it.
3 decent subs are better then 1 perfect one anyday of the week. Leaving out the old can only be in one place, 3 means you can have one up, one refiting and one being worked up allowing better crew life and like.
From Defense News: Navy delays next-generation submarine start to early 2040s
By Megan Eckstein
The U.S. Navy is pushing back the start of construction on its next-generation attack submarine by nearly a decade, citing tight budgets and a need to fund current and near-term operations.
A Navy spokesperson told Defense News construction on the lead ship of the SSN(X) program, which will follow the Virginia-class attack submarine, is now planned to start in the “early 2040s.” The Navy last year planned to begin the ship class in 2035, and it was previously set for a 2031 start.
In its fiscal 2025 budget, the Navy is seeking to delay spending on several modernization programs, including SSN(X), the DDG(X) next-generation destroyer, and the F/A-XX next-generation fighter.
Three years ago, in the spring of 2021, the Navy was readying for a FY28 start for DDG(X), an FY31 start to SSN(X), and a generic 2030s start to F/A-XX, the manned fighter that fits into a larger Next Generation Air Dominance family of systems.
The service has already delayed the DDG(X) program to a FY32 start, reflected in last year’s budget request. Navy Secretary Carlos Del Toro previously told Defense News he didn’t want to rush the DDG(X) program and wanted to ensure the technology and workforce are ready for the transition from the Arleigh Burke-class destroyer to the follow-on program.
The Navy spokesperson said the DDG(X) is still planned to go into construction in FY32, despite delayed research and development dollars in the FY25 budget.
The spokesperson did not have an updated timeline for F/A-XX, though the Navy has historically been tight-lipped about the program.
Navy Undersecretary Erik Raven spoke about the budget request on March 8, noting “our guidance directs us to take risk in future modernization when there are hard choices to be made.”
“If you look at F/A-XX, or the other X [next-generation] programs, we knowingly took risk in the schedule for development of those programs in order to prioritize those key investments — whether that’s readiness, or investing in our people, or undersea, to make sure that we make those programs whole,” he added.
Raven on March 13 told Defense News that, for “any acquisition program, we are looking to move out in the most responsible way forward. And that includes the ability to develop the technologies to the right level of maturity, to make sure that they are inserted in programs at the right point.
“That does take investment, and again, we are taking risk in some of these areas. But fundamentally, no matter what our budget levels, we have to run good acquisition programs,” Raven continued.
The Navy is asking for $586.9 million for SSN(X) design and development efforts in FY25, up slightly from the $544.7 million it requested in FY24.
It seeks $102.7 million for DDG(X), down from FY24′s $187.4 million request. And for F/A-XX, the Navy wants $454 million in FY25, compared to $1.5 billion in FY24.
4,000 feet does get you down into the SOFAR channel in most of the world, if you wanted to do that. With Royal Navy design philosophy, and a 33 foot hull diameter, that means a design collapse depth of 7,000 feet.
Basic hoop stress equations give you a required plate thickness of 157mm. That's going to be pretty darn heavy, but is a long way from battleship armour. Admittedly that's a very simplified approach - I don't do submarine structures, and I'm intentionally not asking the people who do.
I'm pretty sure the hull plating is nearly that thick on Ohios (HY80 hull and a test depth of not much "in excess of 800ft"). Hull frames are definitely around that thick.
So I was going to the appropriate multiple of that for Deep Sound subs.
The U.S. Navy is pushing back the start of construction on its next-generation attack submarine by nearly a decade, citing tight budgets and a need to fund current and near-term operations.
A Navy spokesperson told Defense News construction on the lead ship of the SSN(X) program, which will follow the Virginia-class attack submarine, is now planned to start in the “early 2040s.” The Navy last year planned to begin the ship class in 2035, and it was previously set for a 2031 start.
The Navy moved its SSN(X) from a 2035 start to the "early 2040s," as it takes risk in modernization programs to pay for current operations and readiness.
Just to add to this...Seawolf can't TLAM anything....as there are no Torpedo Tube Launch Tomahawk in US stocks. Appears the capability went away in 2015 when the RN purchased the remaining USN stocks for the Astute Class.
Just to add to this...Seawolf can't TLAM anything....as there are no Torpedo Tube Launch Tomahawk in US stocks. Appears the capability went away in 2015 when the RN purchased the remaining USN stocks for the Astute Class.
Honestly a little surprised that the Navy didn't order ~150x TTL Tomahawks then. SSN21s hold a total of 50 weapons internally and probably went out in the 1990s with ~24x Tomahawks, that 150x TTLs would be a full load and a reload for each boat.
And it'd give some options for other boats to go out and put a few TTLs in the torpedo room to allow for greater strike loads. Not that a 688i or Virginia can put more than 15 Tomahawks out in a single shove. Gotta save 1 torpedo tube for an actual torpedo to shoot at someone hunting you.
Honestly a little surprised that the Navy didn't order ~150x TTL Tomahawks then. SSN21s hold a total of 50 weapons internally and probably went out in the 1990s with ~24x Tomahawks, that 150x TTLs would be a full load and a reload for each boat.
And it'd give some options for other boats to go out and put a few TTLs in the torpedo room to allow for greater strike loads. Not that a 688i or Virginia can put more than 15 Tomahawks out in a single shove. Gotta save 1 torpedo tube for an actual torpedo to shoot at someone hunting you.
There really are only two operational SSN-21s, as the Jimmy Carter is mostly/entirely reserved for…. so it isn’t worth the bother of acquiring tube launched Tomahawks. If I had to guess, the Seawolf class is expensive and difficult to maintain that the class will be prematurely retired, aside from the Carter. Unless the navy wants the boats simply to act as placeholders to justify a new class of large diameter SSNs.
There really are only two operational SSN-21s, as the Jimmy Carter is mostly/entirely reserved for…. so it isn’t worth the bother of acquiring tube launched Tomahawks. If I had to guess, the Seawolf class is expensive and difficult to maintain that the class will be prematurely retired, aside from the Carter. Unless the navy wants the boats simply to act as placeholders to justify a new class of large diameter SSNs.
There really are only two operational SSN-21s, as the Jimmy Carter is mostly/entirely reserved for…. so it isn’t worth the bother of acquiring tube launched Tomahawks. If I had to guess, the Seawolf class is expensive and difficult to maintain that the class will be prematurely retired, aside from the Carter. Unless the navy wants the boats simply to act as placeholders to justify a new class of large diameter SSNs.
All 3 boats are attached to DEVRON in Bangor. Connecticut is broken right now so is basically in shipyard, so Seawolf is back up doing missions that don't need the Carter's ocean interface section.
Before CT found that seamount, it was Seawolf in shipyard to support CT and Carter.
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