Arihant-class SSBN - News & Discussions
- Thread starter Nick
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Presented on the occasion of launch of S3 - Arighaat in Nov 2017.
Design seems to be maturing well. Unlike previous S5 models, these ones don't have sudden bulge ahead of the SLBM silos. Now, the missile silos have a gradually blended design. Also, the sub now has a rather interesting control pane setup.
The sub design retains the fairwater dive panes on the sail & the tail vertical rudders from the Arihant class. But the horizontal panes now have additional control surfaces. This will probably improve maneuverability at slow speeds &/or when surfaced.
White vertical tube thing represents the silo? then 6+6 total 12 silos? and dual setup shown ie single larger dia slbm and multipack lesser dia slbms? Assuming higher dia ~ 2m, maybe slightly less
Which is pretty surprising...considering the size of the hump depends on the size of the SLBM you plan to use from it. Unless our intended SLBM specifications have changed (read: better propulsion tech resulting in a shorter missile with the same range as before), I don't see how they can redesign the hump to be more blended without changing the Sub's beam diameter itself (which essentially means going back to the drawing board and starting from square one).
Yeah, the models seen previously had the dive planes on the hull (like on Vanguard-class) and not on the tower. It seems we're testing various different configurations, as we should. This does however reinforce the notion that there probably isn't a frozen design yet.
Does anyone know when this photo was taken? We know the previous model was in testing as of 2018.
pic is from the newsletter this month, and suggests taken recently as last month itself, 25 january.
Walchand Industries provided the following list of equipment for a BARC designed "mobile reactor":
They are obviously talking about BARC's CLWR-B1 reactor that powers the Arihant class SSBNs. They have also supplied to BARC this 1.1m dia high strength spherical vessel:
This is probably the lock-out door that separates the reactor from the rest of the propulsion machinery. Walchand also produced & supplied the 9m dia pressure vessel that encloses the propulsion unit (reactor + turbomachinery):
This is the same vessel that we can see here on the land-based CLWR-B1 reactor:
The propulsion vessel is 9m in diameter. The whole sub is 15m in diameter. Arihant class has the typical Soviet/Russian double hull design. Also, publicly available info says that Arihant class subs can dive to a depth of 300m. Water pressure at 300m would be around 30 bars. This pressure vessel is rated to survive 70 bars of pressure.
That depth figure is probably understated.
They are obviously talking about BARC's CLWR-B1 reactor that powers the Arihant class SSBNs. They have also supplied to BARC this 1.1m dia high strength spherical vessel:
This is probably the lock-out door that separates the reactor from the rest of the propulsion machinery. Walchand also produced & supplied the 9m dia pressure vessel that encloses the propulsion unit (reactor + turbomachinery):
This is the same vessel that we can see here on the land-based CLWR-B1 reactor:
The propulsion vessel is 9m in diameter. The whole sub is 15m in diameter. Arihant class has the typical Soviet/Russian double hull design. Also, publicly available info says that Arihant class subs can dive to a depth of 300m. Water pressure at 300m would be around 30 bars. This pressure vessel is rated to survive 70 bars of pressure.
That depth figure is probably understated.
Mere speculative/forward looking assessment, but one market research doc last year mentioned S5 project approval with likely initial funding clearance, I guess. Together with the recent hints we have seen, this is likely the cycle to start soon after one completes.
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8000 km ranged K-8 SLBM. This is the 1st time I have read that name. Wasn't the K-6 supposed to have 6000-8000 km range. There were some talks about the possible conversion of the newer lighter A-5 to a SLBM. Been thinking about this for a while. Let me speculate a bit:
Some OSINT handles estimate that the MIRVed A-5 is shorter than the initial A-5.
If this estimate is accurate then the A-5 MIRV is about 1 m taller than the Trident D5 SLBM. If we were to directly convert the MIRVed A-5 into a SLBM, this would be the tallest SLBM in service anywhere in the world. The A-5 has higher payload capacity than the D5. A-5 can carry 4 tons of payload to max range while the D5 can carry 2.8 tons.
Technically it is possible to directly convert the A-5 to a SLBM depending on the size of the submarine that will carry these missiles. Or we could reduce the length of the missile & thus lose out on some of the payload capacity, make it similar is specs to the D5.
Some recent photos of the hydrodynamic models of S5 shows a blended SLBM hump. So, either the future SLBMs will be shorter in height or the S5 sub is going to have a larger dia. I am leaning towards the later.
The S5 class SSBNs are going to be at least as big as the Akula III/Yasen class submarines if not as big as the Borei class submarines. The propulsion set up of the S5 class is almost exactly the same as that of the Borei class.
A 190-200 MWth PWR feeding a 32-38 MWe steam turbine. The electricity generated is sent to a large electric motor which further powers a pump-jet propulsor.
BARC's CLWR-B2 PWR is the 190 MWth reactor will power the S5. BHEL will provide the steam turbine needed to generate electricity. In 2020, it became known that DRDO & pvt. industry was jointly developing a pump-jet propulsor powered by a 35 MW electric motor.
No. of missiles carried is also the similar. Borei class carries 16 Bulava SLBMs. IN wants the S5 to carry 12-16 SLBMs.
Propulsion set up & missile load-out has the largest role in determining the size of a submarine. If both these criteria are so similar, it stands to reason that the end product will end up being similar in size.
Was thinking about this part, while we have seen the visible progress in aerdynamic design & compactness of the A series, the same seems to have transitioned in there well. This pic is not sure about scale, but definitely a good measure. Depending on tube dia & the sub capacity to launch there is definite some breakthrough.
I thought it was something speculative, though the rest of the research doc is quite well done. If I had to guess, I think k5 would be 1.9m dia similar to A5, not sure A6 what it is gonna do, maybe one is non-mirv though that does not make sense. Veda with a 2.5m dia first stage will see transition into SLBm hopefully, so we have scope for
K-5 all stages crmc max 2 m dia
K-6 all stages crmc with first stage from veda 2.5m then k5 2nd stage 2 m on top of it ?
this K8 thing above could be all stage 2.5m dia crmc ?
is it feasible? new sentinel icbm of US seem to have varied dia stages proposed, I am not sure if ours could have varied dia stages inside S4 or S5 class and launch underwater.
Maybe its just a rumour without basis. there is no evidence of this k8 anywhere tbh. Even K6 not so much.
All SLBMs worldwide seems to have 2-2.2 m dia. It is certainly possible to have a 2.5 m dia SLBM, that would also reduce the height. But I wonder if our subs can accommodate that.
Land based ICBMs have more design freedom than SLBMs.
True. Could just be an error.
K6 has not been sanctioned yet. Navy wants to see how the K5 does before funding yet another missile program.