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Originally Posted by dragracer567

Japan is planning to build it's largest post-WW2 warships. The plans entail building two 20,000-tonne missile defense ships that will field the AEGIS Ashore system for defending Japan from ballistic missiles originating from North Korea (the most likely culprit), China or even Russia given the rising tensions as Japan is among the few countries that is directly threatened by both Russia and China. Fielding these ships would also apparently mean that Japan's existing destroyers can concentrate on the role of maritime security rather than air defense. The two new ships would cost about $7.1 billion or about $3.55 billion each. At present, their biggest ships are the Izumo class helicopter carriers has a fully loaded weight of 27,000 tonnes (19,000 tonnes empty) while their biggest destroyers - the Maya class are around 10,500 tonnes.

This is an interesting story but I was a bit confused. Isn't Aegis Ashore the land based variant of the seaborne ballistic missile defence system of the same name? Surely then these (effective) battlecruisers will just be having a souped up version of the regular flavour Aegis system. I do remember reading that many proposals were mooted, such as having a missile defence barge or platform (a bit like the recent Netflix movie Interceptor) but were dropped. I know the Japanese public had concerns about adverse health effects from the powerful radar radiation from Aegis Ashore, not to mention a land based system becomes a pretty compelling stationary target in day 1 of a shooting war.

At the cost that these are being built, my first concern was that surely concentrating all your ballistic missile defence eggs in two big baskets simply makes targeting them easier for the opposition - would it not make sense to build more Aegis equipped destroyers of the type the JMSDF already fields? Therein I found the real limiting factor. Crew complement - these giant battlecruisers are projected to only have a crew of half or less than the existing destroyers in JMSDF service - all in line with the broader scale manpower issues afflicting the Japanese self defence forces.

My main concerns are these - published results from a similarly massive modern destroyer with a very lean crew complement, the Zummwalt class, were not promising. Whilst the savings from regular operation with reduced headcount was fine, attrition damages would severely impact the ability of the destroyer to function at full war fighting potential. These giant Japanese destroyers will no doubt become primary targets for the North Korean navy or the PLAN, even the RuN (were it to come to that). The JMSDF would have to task escorts for each of these ships, assuming one is at constant patrol to provide the shield to the archipelago. I'm guessing the lessons for automation from the Zummwalt would have to be closely regarded to see where the Japanese can reduce manpower load whilst still maintaining sufficient battle attrition redundancy for key subsystems.

These are effectively the first battlecruisers to be built in the 21st century. these ships will be about 70% bigger than both the Chinese Type 055s and the American Zumwalt class! I'm assuming that the Americans and the Chinese would eventually plan similar ships if the design works. India's next set of destroyers - the Project 18 will apparently have an element of ballistic missile defense as well though planned to be smaller at around 12,000 tonnes.

All that being said, if these ships Do come to pass, it'll be quite the new milestone in this current naval arms race we're witnessing globally. I've seen some interesting concepts floating (pardon the pun) around for the hull design of this behemoth, one including a catamaran hull - might be more useful in terms of stability for a ballistic missile defence system at sea. I know a criticism against the INS Vikrant brought by one member was the vulnerability to ballistic missiles - I definitely feel it's a natural progression for the IN to include a home brew ballistic missile defence system on home grown destroyers. From what you say though, these will comfortably be the biggest surface combatants (not including aircraft carriers) built in India. Look forward to seeing them fielded by the end of the decade (imagine that's about the most optimistic we can be for realistically seeing them at sea).

Slightly off topic I've not come across much about India's domestic ballistic missile defence initiative, I imagine that's clearly by design. Anyone able to point me if there's been any chatter on T-BHP to that effect in another thread?

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Originally Posted by V.Narayan

Attachment 2357259
The old INS Taragiri which decommissioned in 2013 after 33 years of service

Attachment 2357266
Artists rendition of Project 17A vessels

Forgot to ask something that the overhead image of the Project 17A had me thinking. A somewhat random question based on something I noticed for the first time recently. I came across an overheard shot of one of the Kolkata class destroyers when I noticed that the two intake-outtake stacks were placed offset from each other - one was to the starboard side and another to the port side.


Example image

That had me wondering - is this common practice in warship design? Just out of curiosity, what exactly is the utility of this choice?

Another observation I made from all the media from the recent INS Vikrant commissioning is to do with the IN dress uniform - is it me or have the peaks of the caps (both baseball cap style and the regular military uniform cap) become longer? The brims felt noticeably wider and protruded a lot more. This is obviously a aesthetic gripe but whenever I see caps having way oversized peaks and brims, I can't help but think of the cartoonishly oversized and rather silly head gear the top brass of the Iranian military sport. Was there a recent revision to the headgear used by the Indian Navy in particular? Or am I just seeing things?

[V.Narayan]

Originally Posted by ads11

.... when I noticed that the two intake-outtake stacks were placed offset from each other - one was to the starboard side and another to the port side.

That had me wondering - is this common practice in warship design? Just out of curiosity, what exactly is the utility of this choice?

- is it me or have the peaks of the caps (both baseball cap style and the regular military uniform cap) become longer? The brims felt noticeably wider and protruded a lot more. This is obviously a aesthetic gripe...

The Kolkata class and its parent the preceding Delhi class have their forward engines fitted more to the left and aft engines more to the right of the centreline. Also fore and aft. A part of separation to help reduce risk of damage by a single large missile.

As for the cap peaks I have observed this 'large peak' fashion trend not inly in the Navy but in the Army too. I do not know the regulation but it seems to be the choice of the officer concerned. I agree it is an aesthetic no no!

[handsofsteel]

Originally Posted by V.Narayan

The Kolkata class and its parent the preceding Delhi class have their forward engines fitted more to the left and aft engines more to the right of the centreline. Also fore and aft. A part of separation to help reduce risk of damage by a single large missile.

As for the cap peaks I have observed this 'large peak' fashion trend not inly in the Navy but in the Army too. I do not know the regulation but it seems to be the choice of the officer concerned. I agree it is an aesthetic no no!

The observation is true for the SNFs, the Talwar/Teg class as well.
While the reason given for the fore and aft displacement is correct, the primary reason why the two engine rooms are displaced with respect to the centreline is the shaftline. Needless to say, the shafts are symmetrical about the centreline and therefore, the engines need to be offset by an equivalent distance to avoid unnecessarily complicated designs of the gearing/shafting.

Coming to the peaks of the ‘baseball’ caps, these are personalised and pander to the choice of not only the crew, but also by what’s available in the market.
Much like the tapered fit, ‘socks showing’ trousers have practically displaced ‘regular fit’ in stores these days, traditional peaks are rarely available these days even if one wants to get them designed.
It’s worth noting that these caps are not articles of uniform and are therefore not governed by a uniform regulation regarding size/shape etc unlike the peak cap and beret.

[handsofsteel]

Originally Posted by ads11

Another observation I made from all the media from the recent INS Vikrant commissioning is to do with the IN dress uniform - is it me or have the peaks of the caps (both baseball cap style and the regular military uniform cap) become longer? The brims felt noticeably wider and protruded a lot more. This is obviously a aesthetic gripe but whenever I see caps having way oversized peaks and brims, I can't help but think of the cartoonishly oversized and rather silly head gear the top brass of the Iranian military sport. Was there a recent revision to the headgear used by the Indian Navy in particular? Or am I just seeing things?

While your observation regarding the sea (baseball) caps may have some merit, the peak caps remain the same, governed as they are by regulations.
Personally, given a choice, I would-purely for reasons of practicality in our tropical climes- prefer a wider brim to keep the harsh sun out. The Russian/German peak caps (with their non existent brim) are suitable for their climes with practically no sunshine but will be a huge misfit here.

[saikarthik]

While watching the DEFEXPO 2022 news, found that in one of the videos related to NGCMS (next generation combat management systems), there was a futuristic destroyer referred to. Could this be our next generation Project 18 Destroyers? If yes, also one interesting observation is on the VLS(vertical launch systems), at fore has 72 cells, which is pretty heavy compared to the current we have on the Project 15(B) class. Also, the speculation is that these VLS could be like the Mk41 (universal VLS), which could be a huge improvement in the flexibility. But I doubt if the dimensions of current Brahmos is compatible with Mk 41, can anyone enlighten me on this?

Also, interestingly, we now have a high mounted CIWS on the aft in addition to the port & starboard CIWS in the mid section. Any particular advantage we get out of this?

[dragracer567]

Photo from this year’s Malabar exercise which took place in the Sea of Japan/East China Sea. India participated with the frigate INS Shivalik, ASW Corvette INS Kamorta along with the P8i ASW aircraft. The ASW aircraft from the four navies are visible as well in this photo - the P8s from the US, Aussie and Indian navies along with the P1 from the JMSDF.



Additional photos of the ASW aircrafts from the 4 navies and special forces ops (a US Navy Seal and Indian Navy MARCOS visible).





The Malabar exercises are possibly among the most complex multi-lateral exercises right now, encompassing all aspects of naval warfare - whether it’s submarines, surface warfare, aerial domain as well as elite naval special forces operators and God knows what isn’t revealed in the public domain such as space, EW, cyber etc.

[V.Narayan]

INS Mormugao, second Visakhapatnam class destroyer joins the fleet

https://timesofindia.indiatimes.com/...w/54379510.cms

Interestingly Wikipedia talks of two diesels, one on each shaft in addition to the four Zorya gas turbines! Two GTs and a diesel on each shaft would make for an rather unusual combination - COGAGOD?? Or maybe it is simply misinformation.

After the 10 years each that it took to build the three Kolkata class the 7 years here sounds like an improvement. With the right planning, modular construction and supply chain management the time to build should be 3 years. The fault is not with the builder alone but also possibly with the IN for changing specs too often after construction starts.

[directinjection]

Originally Posted by V.Narayan

Interestingly Wikipedia talks of two diesels, one on each shaft in addition to the four Zorya gas turbines!

Thank you for the info, Narayan jee! What is the power output of these turbines? What impact is the Ukraine war likely to have on spare part supply? Are there any chances of the home-grown marine Kaveri being used in Indian Navy's ships? Is Kaveri not good enough even for ships? Kindly share your thoughts!

Originally Posted by V.Narayan

After the 10 years each that it took to build the three Kolkata class the 7 years here sounds like an improvement. With the right planning, modular construction and supply chain management the time to build should be 3 years. The fault is not with the builder alone but also possibly with the IN for changing specs too often after construction starts.

Agreed!

[handsofsteel]

Originally Posted by V.Narayan

INS Mormugao, second Visakhapatnam class destroyer joins the fleet

https://timesofindia.indiatimes.com/...w/54379510.cms

Interestingly Wikipedia talks of two diesels, one on each shaft in addition to the four Zorya gas turbines! Two GTs and a diesel on each shaft would make for an rather unusual combination - COGAGOD?? Or maybe it is simply misinformation.

Misinformation

Originally Posted by V.Narayan

After the 10 years each that it took to build the three Kolkata class the 7 years here sounds like an improvement. With the right planning, modular construction and supply chain management the time to build should be 3 years. The fault is not with the builder alone but also possibly with the IN for changing specs too often after construction starts.

Not really, complex geopolitical situations like the ongoing war, availability of berths with the yard (considering parallel commissioning of the P75s, 17As, ongoing refits), cash flow etc do play their part. Not to forget, covid played its part with a total shutdown. Also, considering the long life of ships-40 years- makes sense to take a hit now and incorporate something new rather than wait 6 years down the line, not that there have been significant/major changes from the Kolkatas.

[Gansan]

Aren't all these vessels powered by Ukrainian gas turbines? How reliable are they for maintenance and support under the present circumstances?

[V.Narayan]

Originally Posted by Gansan

Aren't all these vessels powered by Ukrainian gas turbines? How reliable are they for maintenance and support under the present circumstances?

This is a staple Soviet design manufactured in what has now become Ukraine. From what little I know and the fact that the IN has 32 of them installed and, in case of INS Delhi, running since 1997, I suspect they are reliable machines. Impact of the war - hard to tell. though I suspect we carry a lot of spares including whole turbines in our inventory.

Originally Posted by handsofsteel

Misinformation

Thank you. My guess too.

Originally Posted by directinjection

Thank you for the info, Narayan jee! What is the power output of these turbines? What impact is the Ukraine war likely to have on spare part supply? Are there any chances of the home-grown marine Kaveri being used in Indian Navy's ships? Is Kaveri not good enough even for ships? Kindly share your thoughts!

Going by publicly available data these turbines Zorya D59's generate 16.5 megawatts each, I presume at ISA 15 degrees centigrade. In tropical ambient conditions of say a normal max of 34 degrees that would drop to around 12.5 MW each. Sailors and aviators don't think in terms of MW or SHP but in terms of revolutions. I do not know about Kaveri coming in as a marine gas turbine. They have not yet built the successful aviation turbine yet. Marine turbines apples to apples are more complex because they - (i) operate in salt laden sea air; (ii) have to operate, at least for us, at high ambient temperatures; (iii) deal with mechanical forces that the propellor, shaft and gearbox of a ship throw on the marine turbine which are all out of proportion to anything a jet turbofan faces operating most of its life in super cool, super clean air at 36,000 feet. So first we need to learn to design, build and prove an aviation jet and then marine turbine is the second step. My views strictly. Others may differ. Hope this helps.

Very recently INS Delhi completed 25 years of yeoman service to the nation. The INS Delhi design was the 'We have arrived' coming out party for Naval Constructors of the IN. The basic design has remained largely unchanged through Delhi-Kolkata-Visakhapatnam. In June 2005 at an International Fleet Review in the UK, Prince Philip, himself ex-Royal Navy chap adjudged INS Delhi to be the most handsome and well-proportioned ship on parade that day.


INS Mumbai, third of the Delhi class, underway




The original INS Delhi, a Leander class light cruiser, and the cradle of the modern Indian Navy. It was said to house a ghost on its rolls. And the occasions the ghost appeared was duly recorded in the ship's log. You can read about it here - https://www.team-bhp.com/forum/shift...ml#post4203669 (Spooky Experiences : Share them here)

[directinjection]

Originally Posted by V.Narayan

I do not know about Kaveri coming in as a marine gas turbine. They have not yet built the successful aviation turbine yet.

Considering the number of years the marine Kaveri has been under development with not much to show by way of results, it's probable that our approach towards the project is lackadaisical, as usual. I'm not sure if adequate funds have been allotted and proper facilities created for the project.

I was able to locate the following reports on the subject (the oldest item is from 2008) and unfortunately, things don't look very encouraging!

https://pib.gov.in/newsite/erelcontent.aspx?relid=40470
https://www.business-standard.com/ar...0800089_1.html
https://www.drdo.gov.in/kaveri-marine-gas-turbine
https://idrw.org/drdo-to-have-anothe...-turbine-kmgt/
https://www.cassindia.com/reach-new-...pulsion-system
https://www.businessworld.in/tags/Ka...urbine-238582/
http://archive.indianexpress.com/new...ersion/336967/

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Originally Posted by dragracer567

Attachment 2380182

Fascinating image this. I think this is the first time I've seen the Kawasaki P-1 juxtaposed directly against the comparable P-8. It's a real shame the Japanese haven't had much luck with the P-1 and that platform, I find it a really interesting project but I guess it's a Sisyphean endeavour when competing against twin-jet running costs and a platform based off the ubiquitous 737.

I wonder how easy in future it might be to convert the P-1 platform to a twin jet and if that might make it more palatable from a running cost standpoint as a fixed wing ASW counterpart to the Poseidon (which seemingly is the de facto choice for NATO and similar naval forces).

Going back to the destroyers. Does India license manufacture the marine turbines? The Zorya ones? Are there any plans to do so given how ubiquitous they seem to be in the fleet? Just going off memory, aren't some of the newer vessels like the Vikrant for eg using marine turbines of US origin (design at the very least)?

[dragracer567]

Originally Posted by ads11

Just going off memory, aren't some of the newer vessels like the Vikrant for eg using marine turbines of US origin (design at the very least)?

Based on what I know, our newer indigenous frigates - the Shivalik class and the Nilgiri class run the American (locally assembled) GE turbines (same one from the Vikrant) combined with diesel engines (CODOG). The Russian origin Talwar class frigates including the ones currently under construction in Russia & ones supposed to be made in India (and delayed due to the war) and all our destroyers including the latest Vishakhpatnam class run the Zorya turbines (COGAG) - assuming because our indigenous destroyers are still influenced by the Delhi class destroyers. I suppose it’s not that easy to put a gas turbine into a ship that wasn’t designed for it.

Last I remember about the Zorya turbines was that the Russians bombed their main factory quite early during the war and then offered India an alternative they use in their ships as a Zorya replacement (since they obviously can’t get spares from Ukraine).

Anyway, unlikely we will use either Zorya or Russian engines in our future designs. Our future destroyers and frigates will probably run diesel-electric + Gas turbines mostly likely produced in collaboration with Rolls Royce. The problem is, we still have ships under construction and planned that are supposed to use the Zorya engines.