The Submarine Matters article France's Innovative Submarine Industry eg. Scorpenes of August 11, 2023, prompted an avalanche of comments from August 11 to 15, 2023. I won't attempt to address all issues raised, but some of them.
French Naval Group's (NG) Scorpene SSKs (17 sold to 4 customers) are more equivalent to German TKMS' non-AIP Type 209s (90 sold to 15 countries). The Scorpenes and 209s are capable and less expensive than Type 214s (whose relatively expensive AIP tends to be for specialised uses like missions in the Yellow, Black, East China and Mediterranean seas).
Whether the NG conventional Barracuda (see this Youtube with cc subtitles on and NG website), TKMS (website link Type 212CD E) or Saab (with its website link C718) are likely to win the Netherland's Walrus Replacement Competition, perhaps announced in 2027, is anybody's guess. Much depends on the Netherland's Navy and broader Dutch government's requirements, which are complex, confidential and perhaps even changeable as differing technologies mature.
Countries with long submarine building histories and whose submarine forces are all conventional (particularly Sweden and Germany) have some advantages in submarine and AIP design and industrial focus. This is compared to countries attempting to build conventional and nuclear subs (like India and Russia, both with no AIP) or France with an all nuclear sub navy while only building conventional subs for export.
China is an exception building nuclear subs (own navy) and conventional subs (for own navy and export) and China has developed second generation AIP and is exporting AIP conventional subs.
Medium sized concept submarines without a fin/sail haven't sold well in the last hundred years for reasons of sea-keeping, safety, command, navigation and security - all especially in the surfaced approaches to and from port and in emergency ascents.
The issue of submarine customers choosing Lithium-ion or Lead-acid Batteries and AIP is very complex. The distances and mix of missions a customer expects are relevant. Also is the customer country building its own, exporting or importing subs? Economies of scale, money available and whether the customer is also developing nuclear subs all come into it.
7 comments:
Regarding the question of AIP vs Lith-Ion, my answer would be very plain and simple: why not both? An AIP submarine will always also require some amount of batteries as a kind of "buffer" for the AIP system and for additional safety and improved silent running capability, among other reasons. I'd estimate that a Type 212A merely running on batteries still has roughly the range of a modern medium-sized SSK. This battery-only range will be even furtherly increased with Type 212 CD's lithium batteries.
Going with a fully lithium-ion battery setup without AIP made sense for Japan, which has always been leading the development of such technology and doesn't have a working, domestically producable AIP system, and whose submarines probably have enough opportunities to recharge their batteries in the Pacific.
Hi Pete
To Autistry
Yes and no is my answer
-Due to its limited speed in an AIP mode, batteries ,(Li better), are needed for the most obvious main functions:protecting naval assets on the move , following/shadowing, unfriendly assets, hunting subs..where speed is esssential
-If you look at the W European theater, we are talking of areas at bare minimum extending from Cape Finisterre in Spain to N Iceland This area is typically 1000 miles aways and a 3 weeks missions involves 2 weks of transit time in AIP only (long time , things change in one week , low efficiencies of your sub assets (need more for the job)..and so on.The situation in the Atlantic , Pacific or Indian Ocean is even more detrimental to AIP balance
Rightfully, therefore, you need both in theory, however the balance beetween cost/complexit/space used vs extra Li batteries, which can also stay underwater for a week at a few knots is not as clear cut .What are the marginal gain if any in typical situations?
BTW I disagre with your view of the limited speed allowed by E motor.Very large motor(Perm, mag) are available certainly on the Barracuda dual mode (7 Mw?, 9/10 knots ?).The turbine mode is not as silent due to inevitable vibration transfer through the shaft (above 10 knots, strategically critical however
Hey Anon
for me, it is important to note that the chemical tanks for fuel cell AIP (for TKMS, currently oxygen and hydrogen) will always offer a better space/weight to endurance rate than Li-ion batteries. And there are significant advantages from a design perspective as well, most notably that these tanks can and should be situated outside of the pressure hull, giving the pressure hull itself a smaller diameter, which is associated with a wide range of advantages like a reduction in required steel thickness and therefore less weight. If we got rid of a modern fuel cell submarine's AIP in favour another deck of batteries (coming at the cost of a much-enlarged pressure hull), the submarine would get significantly larger while the submerged endurance wouldn't get nearly the same boost as it would get with fuel cells.
A scenario where sacrificing AIP for Li-ion batteries likely makes more make sense is when we're talking about submarines that are supposed to be so high-range that they can reach virtually every place in the world and stay deployed for months on end -- without ever reaching a port to recharge its chemical tanks. Ironically, this is more or less what the Dutch are looking for with their replacement programme, but the two main contenders both offer designs that focus mainly on AIP while giving batteries a secondary role. I wonder whether Naval Group is speculating about offering a Shortfin Barracuda with lithium batteries, but considering how the Australian boats entering service in the 2030s would've all had lead-acid batteries, it seems like NG still has a long way to go before it can offer such technologies...
Regarding your comment on limited speed on conventional submarines, I am well-aware that modern submarines are not purely limited to extremely low crawling speeds and never said such. It's also not a very recent innovation that submarines can cruise at around 10 knots for longer distances. The extremely well-designed (but ultimately ill-fated) TSNW TR-1700 submarines built for Argentina had an (official!) submerged range in excess of 300 nm at 10 knots, which is quite impressive if you consider how rapidly submerged endurance usually shrinks as you increase speed while running on batteries. But even this is a joke compared to nuclear submarines, whose cruising speeds are technically only limited by what the turbines can mechanically sustain, which is most certainly far in excess of 20 knots. By contrast, even the most modern conventional subs running at their top speeds of roughly 20 knots are limited to only a few hours of submerged endurance at this rate. The enormous strategic disadvantage ensuing from this lack of high-speed cruising range is very blatant, to be quite frank.
I think I'll have to add to what I just wrote, because the long-range conventional submarine issue is not so clear-cut that we can definitively say that Li-ion is always better. I believe, and this is probably very important with regards to the future of AIP and Lithium Ion implementation in submarines, that it very much depends on the mission profile -- even when we're talking about long-range submarines such as the ones the Netherlands will order.
If the Navy expects its submarines to repeatingly surface (or snorkel) and submerge while operating for many weeks at a time, a pure-battery setup can be reasonably considered the better choice, as the rechargeability of the batteries then fully unfolds its strategic perks. But if the long-range submarine is mainly just supposed to be capable of reaching faraway operational areas without regular occasions forcing it to fully submerge while on transit, the batteries would rarely be used as the submarine spends nearly all of its time snorkeling under these conditions. The submarine would only have to stop running on diesel once it reaches its operational area, and then, fuel cells (and likely a Stirling engine as well) are at an advantage because they can be expected to offer better range, which can be very helpful for the submarine to carry out its mission. On the other hand, we can also assert that this increase in continuous submerged range is only relevant when the submarine's mission really requires it to stay submerged for weeks on end, and its hard to say -- at least for me -- how often that would be the case. So it's a tricky issue, one that very much depends on how the customer plans to use its submarines!
I also just remembered the points you or someone else made about the detectability of a snorkel nowadays. Even if you're correct and a snorkel is really that hard to detect with the most modern radar tech, it still presents an ineliminable risk for the submarine, which, no matter how large exactly, will always be large enough that it has to be accounted for. It is therefore in my opinion completely out of the question for a submarine to snorkel when the enemy is known to actively search it, which is yet again disadvantageous for a submarine with only batteries.
Hi Anonymous at 8/17/2023 5:28 PM
I particularly liked your comment, of moderate length, when you wrote:
"Rightfully, therefore, you need both in theory, however the balance between cost/complexit/space used vs extra Li batteries, which can also stay underwater for a week at a few knots is not as clear cut. What are the marginal gain if any in typical situations?"
And I would add, some submarine customers, like Australia's defunct Attack-class project, did/do have safety concerns about LIBs heat buildup possibilities. This was a significant possibility in early experience of LIBs usage in mobile phones, on aircraft and in a US diver delivery vehicle incident.
With years more experience of LIBs heat stability management, mainly for non-submarine uses, submarine builders in Northeast Asia (initially) and now in Europe air more confident using sub LIBs.
Yet LIBs still remain an expensive option compared to Lead-acid batteries (LABs) for subs. Those costs may still incline some customers in the direction of AIP. Possibly Israel and Singapore, who use AIP for weeks of largely immobile (3 knots?) or sitting on the seabed in littoral seas.
Regards Pete
Hi Submarine Autistry at 8/18/2023 6:39 AM
I particularly agree with:
"I think I'll have to add to what I just wrote, because the long-range conventional submarine issue is not so clear-cut that we can definitively say that Li-ion is always better. I believe, and this is probably very important with regards to the future of AIP and Lithium Ion implementation in submarines, that it very much depends on the mission profile"
And that is also relevant for shorter range sub missions in the Baltic, Mediterranean and Yellow seas - and in the Sea of Japan. In those latter 2 seas South Korea is/will be gradually moving to LIBs & AIP KSS-IIIs while and Japan is slowly replacing LABs & AIP Soryus with LIBs Taigeis. Both South Korea and Japan have confidential nuclear propelled, nuclear armed sub concepts, if needed.
Regards Pete
"Possibly Israel and Singapore..." (smiley) INS "Drakon" and Type 218 SG, made in Kiel. Frank Behling https://www.instagram.com/p/Cv0P0kmokqT/?utm_source=ig_embed&ig_rid=40323b34-7226-49d2-9db3-6aa141139ba6 P.S. https://www.israeldefense.co.il/node/59327 ״מטרת gentleseas נכתב באתר הסנפיר/מפרש עשויה להיות רק לייעול/שקט, או להכיל יותר תרנים/חיישנים או אולי לשכן בין 2 ל-4 טילים משוגרים אנכית ("Written on the gentleseas website. The purpose of the fin/sail may only be for streamlining/quiet, or to accommodate more masts/sensors or perhaps to house between 2 and 4 vertically launched missiles"). (https://gentleseas.blogspot.com/2023/08/) Regards.
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