@Ashwin
For some reason, I'm not getting the notification when some people @ me. I thought it only happened with
@Gautam but it's happening with
@Photon Vish as well.
The exact figures are understandably classified.
Think of it like the Indian Driving Cycle (IDC) range figures that car companies quote when saying their car has, say 500 kms range till tank goes empty. The IDC figure has a certain pre-set mix of driving environments & speeds, like say 70% city driving & 30% highway driving etc. In IDC, the ratio of each measure they use to calculate final figure is public info. With regard to AIP figures, a lot of it is secret, for obvious reasons.
Not only that, the measures will likely be different for each AIP manufacturer/submarine OEM (as there's no statutory body regulating these marketing figures), and sometimes there can be difference in measures for different AIP systems from same country/OEM as well.
I wouldn't spend too much time worrying about the figures they put out because we don't know what measures they're using.
As a general rule, it always scales according to usage. Think of it as a UPS/inverter battery. Heavy load = less time on battery.
Fast transits drain the power quickly. Slow transit will last longer. Hotel load lasts longest.
Whatever figure they are showing in public is probably an average of mixed high/low-power usage. So yes, if you use it exclusively in low power state, it will be higher than the given number.
It can be both. Depends on how the sub is configured.
Thing is, you need electricity to run various things on the boat, not just the propulsive motor. Like the CMS, sonars, IPMS, life support systems, CO2 scrubbers etc. The batteries power all that. Having the AIP charge the batteries allows you to carry out all that from a common power bus. The AIP having a direct line to the propulsive motor means you need redundant buses. Is it done on some subs? I think so.
But I'm pretty sure the norm is to keep the batteries charged at all times. Preventing them from depleting is your No.1 goal for survival. The longer you stay underwater (and the more pressure you're under to not surface, due to enemy aircraft flying overhead or whatever), the more important the batteries become.
All things being equal (like same level of tech in external anechoic tiles), an SSN with electric drive + natural circulation will be as quiet if not quieter than an SSK. Reason I say that is because SSNs are typically larger than SSKs. They have more weight & power budget to work with, which usually results in being able to use much better & heavier damping/isolation tech. You can also afford to use more power-hungry machinery as long as it is quieter in operation.
Operationally, your movements are unrestrained by the need to always keep an eye on your battery levels.
As of pumpjets, they really make no sense on an SSK, I've told you about that before:
Has the design for Project 76 already been finalised? As per last update, it's in detailed design stage. I'm not sure if that was such a wise decision before absorbing the Tech from German Type 214 with Indian specific upgrades, maybe we can built the Project 76 submarines in phases where we...
www.strategicfront.org
"...Pumpjet is pretty much an unnecessary extravagance for a diesel boat anyway. The Shortfin Barracuda's pumpjet was pretty much a way to fleece more money out of the Aussies. A non-nuclear boat is never going to sustain the kind of transit speeds where a pumpjet's cavitation-suppression capabilities can justify the cost. Nuclear boat is a different matter. There's a reason why even the gold-plated SSKs like Type-212CD, Orka or Blekinge-class don't bother with pumpjets..."
So yea, in a high-speed transit, an SSN with pumpjet is inevitably going to be quieter than an SSK at top speed (which will still be considerably slower than the SSN).
Already talked about this with you on that same thread, you forgot?
Anyway, linking the relevant posts:
Has the design for Project 76 already been finalised? As per last update, it's in detailed design stage. I'm not sure if that was such a wise decision before absorbing the Tech from German Type 214 with Indian specific upgrades, maybe we can built the Project 76 submarines in phases where we...
www.strategicfront.org
"...full li-ion in place of AIP (new Japanese approach) is a way to leverage technology to reduce complexity & cost. But AIP+Li-ion (which is what we're likely to adopt) is far superior performance-wise as it gives you the best of both worlds..."
Has the design for Project 76 already been finalised? As per last update, it's in detailed design stage. I'm not sure if that was such a wise decision before absorbing the Tech from German Type 214 with Indian specific upgrades, maybe we can built the Project 76 submarines in phases where we...
www.strategicfront.org
"...AIP is useful to keep as a source for hotel load/slow speed maneuvering while retaining LIB in reserve for high-speed burst. As I said, best of both worlds. The KSS-III already uses this AIP+LIB setup..."
Just a small correction: I think you meant type 214 rather than type 216. As far as I'm aware, type 216 never progressed beyond the conceptual stage. While Germany and Italy operate the Type 212A which is more stealthy because of it's non magnetic hull, the type 214 has much longer range, depth...
www.strategicfront.org
"...Just because it fits Japan's use-case doesn't mean it's the solution for everyone. It depends on what our requirements are. As I said, KSS-III uses an AIP+LIB setup, as that fits the Korean requirement. Our P-75I specifically required AIP + LIB...
...Among other upcoming boats, the Type-212CD (for Germany & Norway) also uses a Fuel Cell AIP + LIB setup. So it's apparent that there are several merits to this type of setup. The Japanese may consider LIB-only configuration as sufficient for their use case in the littorals of the First Island Chain or close by, but the same need not be true for everyone else."
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