Submarine Autistry, on August 4, 2023, provided interesting insights on conventional submarine evolution:
“Right now, I think there are two major trends in
conventional submarine design.
The first is size. For many years, there weren't really any
modern diesel submarines of large size (around 3,000 tons or more) and range
(>15,000 nm). The Soviet Union did have conventional submarines with an
enormous radius of action [eg. Foxtrots up to 20,000nm] and eg. Tango-class. But these had to rely on the aged
principles of the Type XXI submarine (with inferior submerged performance in that German wartime design) in as late as the 1970s. (The succeeding and far more
modern Kilo-class was smaller with a much-reduced range [of up to 8,600nm].) But in recent years, Defense Companies have increasingly come up with
designs of large, AIP-equipped subs that can cover a lot of distance (examples
include Type 216, Type 212CD (E), Saab Blekinge Oceanic, Shortfin Barracuda, Navantia S-80
Plus, Japanese Soryu/Taigei and South Korean KSS-III).
The second trend is VLS cells for SLBM capability, which is most
certainly the purpose of [INS Drakon’s] extended sail. I can imagine Drakon [a
Dolphin 2] to be used primarily as a one-off test platform for the newly
developed missiles so that the technology will be ready by the time the Dakar-class
["Dolphin 3"] boats arrive. Since Israel/TKMS will follow suit after KSS-III kicked off
this VLS trend, I can also imagine cooperation with South Korea for missile
development, although Israel's missiles will likely be quite a bit larger than South
Korea's Hyunmoo 4-4. Certainly very interesting to see such
a large sail [on INS Drakon] a modern submarine when people think they will
disappear entirely within this century, a charming callback to the early Soviet
SSB(N)s! [particularly the Soviet Golf-class SSB that had up to 3 SLBMs in its sail.]
Overall, these two trends clearly point toward an expansion of conventional submarine capabilities into areas that were thus far reserved for nuclear propelled submarines. While I can understand this striving, I'd doubt that the enlarging of conventional submarines can give them the same strategic perks that the nuclear submarine possesses by its very nature (unlimited power!!!; i.e. infinite (submerged) range, blistering speeds). I suppose the biggest benefit of conventional subs, quietness, has already come quite close to its optimum, meaning that constructors are now reorienting toward special features (e.g. “diamond” shape). Also conventional subs have broader capabilities and strategic value (range, armament), while not making the submarine much less quiet than its predecessors - but certainly much more expensive to acquire for potential contractors due to its size.”
I think I should re-emphathize that I find both of these trends, especially that of size, somewhat foolish. The main issue is that a conventional submarine is inherently very limited in terms of speed since the most powerful propulsion unit on a diesel submarine is nowadays always the electric motor, which has to run at economical speeds to provide tolerable range. Even to this day, you need some form of turbine to obtain very high speeds on a naval vessel. The only proven way to implement an AIP turbine on a submarine is Walter propulsion, which was the most promising submarine propulsion system by the end of World War II, but never made its breakthrough in the former Allied navies due to the advent of nuclear propulsion. West Germany experimented with modernised Walter propulsion decades ago, but nothing came of it as there was no need for expensive high-speed subs. Since all German submarines normally were mainly designed for the Baltic and North Sea (and, to some extent, for the Mediterranean), the 206A submarine (typically snorkelling at 6 knots) and the 212A submarine (typically running at 5-6 knots on AIP) could reach their destinations quickly enough.
ReplyDeleteBut when a conventional submarine is designed to reach very remote operational areas, we are suddenly confronted with lots of potential timing problems as it would take weeks for a submarine to, e.g., go from Europe to Asia. A nuclear submarine will always be vastly superior in this sense as its cruise speed is technnically only limited by the maximum sustained output of its turbine(s), and the somewhat recent implementation of pump-jet propulsion confirms that the newest nuclear submarines are all designed to be as quiet as possible at high speeds. A 4000-ton conventional AIP submarine like the Type 216, unlike a 1500-tonner like Type 212A, also has to rely much more on submerged traversal via snorkel, which makes it rather easy to detect via radar, in spite of all measures to make snorkeling more stealthy. In contrast, 212A has a range somewhere north of 2500 nm at 5 knots (perhaps up to 3000 nm if you were to fully discharge both the hydrogen & oxygen tanks and the batteries), allowing it to reach most destinations without ever becoming detectable via radar, all while also being ridiculously quiet, making it near-invisible for sonar as well. Type 216 is said to have a range of 2600 nm at 4 knots, which is also quite enormous, but never enough to reach remote destinations entirely submerged.
The trend of size is ultimately a mere attempt to imitate nuclear submarines. The best example of this is Australia's Attack-class debacle. The French design is very literally the adoption of a modern nuclear submarine for conventional propulsion, essentially a diesel submarine pretending to be nuclear in terms of size and equipment (think of the pump-jet propulsor, which conventional submarines ususally never have, mostly for good reasons...). But this "LARP" does not bring remotely commensurate results! I'm certain the submarine wouldn't have been capable of more than 25 knots submerged, and its submerged range (lead-acid batteries and probably no AIP in the 2030s!) might've been as low as 500 nm at 4-6 knots cruise speed. And at this point, it is very reasonable to ask why you would want to spend billions upon billions for a failed imitation of a nuclear sub when you might as well try to "get the real thing". Now, the AUKUS project is in a very dubious state right now (I think you know more about that than I do), but it's understandable that you wouldn't want to be super excited about the Attack-class deal with France back when it was still planned.
In the end, I'd say Australia should've gone with the Type 216 sub, which probably would've spared them a lot of controversy, but I fear it's too late for that now. Either way, I remain convinced that the displacement a conventional submarine is most effective in is usually not larger than 2,000 tons. To be fair, it is somewhat natural that military equipment becomes larger and heavier with time as equipment becomes more complex and modern; we can observe the same basic tendency in tanks and airplanes. But the sudden spike to >3000 tons is still bigger than it should be. Long-range diesel submarines will always need a lot of time to reach faraway places, making their range only useful for maneuvers that are planned weeks in advance. There's no room for operational spontaneity under these circumstances.
ReplyDeleteThe VLS trend is more understandable, but mainly just for countries with unfriendly next-door neighbors like Israel or South Korea since the operational destination can be reached quickly enough even when traveling with low speeds.
Rather long post. Had to divide it into two in order to not exceed the character limit. We'll see what the future brings.
Recently I was involved in a discussion on the possibility of equipping the future "Dakar plus" a nuclear reactor. Jointly development with the Germans... (smiley) https://www.kn-online.de/lokales/kiel/tkms-kiel-neues-u-boot-dragon-fuer-israel-bereit-fuers-wasser-NFAOI5LCKFGH7FBUDB4NRJUBJU.html VMPL is open for communications. Down, front, equipped with a hangar gateway to exit combat swimmers from the submarine.
ReplyDeleteHi all,
ReplyDeleteI think one factor about SLBM's on modern SSK(B) is somewhat overlooked, and that's the traditional nuclear second strike capabilities submarines offer, whether SSBN or SSK(B).
Israel has (apparently) operated nuclear cruise missile armed SSKs since the INS Dolphin was commissioned in 1999. With the recent events in Ukraine, it is now unclear whether a cruise missile can penetrate air defenses, and the changing Middle-East geopolitical situation makes it sub-optimal if an Israeli submarine fired cruise missiles across Saudi Arabia.
Switching to an SSK(B) with SLBM capabilities would be a logical progression in evolving Israel's nuclear triad. A nuclear-armed Drakar class with 3,000KM SLBMS could lurk deep in the Arabian Sea, yet be able to reach out and touch Tehran.
A second strike capability is also why North Korea created the Sinpo-class, and why the ROK created KSS-III counter with conventional missiles - and perhaps nuclear SLBMs.
Since Donald Trump's diplomacy (https://www.americanprogress.org/article/bridging-divide-u-s-south-korea-alliance/) South Korea has came to a realisation that it can not depend on America, period - which is why there has been a surge of SK weapons development, including nuclear weapons (https://www.bbc.com/news/world-asia-65333139)
Error, Sorry...
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