Current & Future Escorts - General Discussion

Contains threads on Royal Navy equipment of the past, present and future.
Lord Jim
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Re: Current & Future Escorts - General Discussion

Post by Lord Jim »

I have little faith in the NSS. Unless such a document is legally binding to successive Governments it is really only a letter of intent.

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ArmChairCivvy
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Re: Current & Future Escorts - General Discussion

Post by ArmChairCivvy »

ArmChairCivvy wrote:turning the surface ships construction prgrm from a forecast into a plan
Lord Jim wrote: is really only a letter of intent.
Ahh, that sits in the middle of the continuum, so we have moved on from the glass half full/empty :)
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Re: Current & Future Escorts - General Discussion

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Having seen MoD procurement programmes from both inside and out, I have developed a very cynical view of the system. The one year spending process that hinders cost effective procurement, and the constant fluctuation in those annual budgets from year to year caused other lines to be stripped of funding at a moments notice halting the purchase of spares or the repair of larger items. Yes this allowed the yearly accounts to appear balanced, but it always just pushed the financial problems down the road whist increasing the final cost to the taxpayer.

Until Defence spending is driven by need rather then annual spread sheets, things are likely to only get worse.

The NSS is a noble idea, but relying on industry to expand and support our naval ship building capacity without Governmental support is wishful thinking. No other nation has followed this path, instead they have evolved partnerships between themselves and industry sharing both the benefits and risks. Our Politicians are all to willing to accept the credit when a policy pays off, but wash their hands blaming poor management by private firms when things go bad. How is that going to inspire confidence in defence industry and allow them to raise funding to invest in modern facilities and technologies. Historically companies have either gone under, abandoned the defence sector or the swallowed up by larger firms, nowadays usually foreign owned. Even our flagship defence contractor BAe in really a foreign company as most of its assets are overseas and that is where it make its money. It only really has a presence in the UK because successive Governments allowed it to become a lone player after absorbing the majority of its UK based competitors, and therefore remains the sole supplier for most UK manufactured defence programmes.

So unless the Government opens its coffers and actively supports the NSS, I have serious doubts it will result in anything but the five T-31s before it is revised once again, with a whole new set of wonderful aspirations but little substance as the next warship programme, the replacement of the T-45, will almost certainly go to BAe to ensure they maintain an order book so their existence is protected.

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Re: Current & Future Escorts - General Discussion

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Well it is up to all of us to make sure we do what we can to prevent "Cost Accounting" depriving the nation of the defence assets that it needs rather than Accounting for the "Value" of those same items. Sort of like buying a car and telling the Salesman that you want wheels on only 3 of the corners and a pile of bricks for the fourth corner and a spare wheel will also be quite unnecessary as you do not intend to actually use it.

However, it will stand out in your street, when parked on your driveway and nobody will see the pile of bricks.

A totally useless way of car ownership and also of DEFENCE PROCUREMENT. :mrgreen:

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Re: Current & Future Escorts - General Discussion

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Lord Jim wrote:actively supports the NSS
What strategy? The one started in 2015 has already been trashed.
@LandSharkUK

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Re: Current & Future Escorts - General Discussion

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The report the original NSS was based on but not fully adopted.

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Re: Current & Future Escorts - General Discussion

Post by donald_of_tokyo »

From River B2 thread.
Repulse wrote:Read an interview in the recent Guide to the Royal Navy 2020 from Cdr Simon Pressdee (head of the Fisheries Protection Squadron) who announced that the force was increasing from 260 to 480 people. On the face of it enough to man all 5 B2s OPVs and the current force. Not sure where all these people have come from though.... anyone have anymore info?
RN increases 220 person on Fisheries Protection Squadron to keep the 3 River B1 (and handle 5th River B2, I guess?).

220 is more than a full crew of either T45 or T23.

As the "full-time trained crew" number is 1400 soul short, and there are no surplus man-power, one escort might be "forced" to go into extended readiness to handle the improved OPV fleet. Is it a good idea?

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Re: Current & Future Escorts - General Discussion

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donald_of_tokyo wrote:As the "full-time trained crew" number is 1400 soul short
Once again, not all of the 1400 shortfall relates to sea-going crews, especially as the RN has been pushing to fill the sea-going shortages first. (hence the 1SLs statement that the crew shortage was almost solved, some months ago). Moving more to the Fisheries Squadron looks more like keeping the training pipeline going and giving crew more time at sea, while waiting for the T23's and T45s to get through refits and repairs
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Re: Current & Future Escorts - General Discussion

Post by SD67 »

Scimitar54 wrote:Well it is up to all of us to make sure we do what we can to prevent "Cost Accounting" depriving the nation of the defence assets that it needs rather than Accounting for the "Value" of those same items.

However, it will stand out in your street, when parked on your driveway and nobody will see the pile of bricks.
:
There’s nothing wrong with cost accounting if you know what you’re doing. I was trained by a German tier one automotive that judged capex based on Total Cost if Ownership over the project life. Pushing to the right increases total cost. It’s short termism that’s the problem.
But this is always going to be difficult for a democratic government unless there’s a bipartisan national consensus on defence. We don’t have that in the UK so there always going to be a juggling act. In fact very few democracies outside the US have that - Australia, and who else?

Personally I’d like it if there was some kind of national defence council including the opposition parties who’d set out a bipartisan 20 year vision of core capabilities, starting with successor and working down. Then you build the procurement strategy around that. But not going to happen with current crop of leaders

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Re: Current & Future Escorts - General Discussion

Post by donald_of_tokyo »

Caribbean wrote:
donald_of_tokyo wrote:As the "full-time trained crew" number is 1400 soul short
Once again, not all of the 1400 shortfall relates to sea-going crews, especially as the RN has been pushing to fill the sea-going shortages first. (hence the 1SLs statement that the crew shortage was almost solved, some months ago). Moving more to the Fisheries Squadron looks more like keeping the training pipeline going and giving crew more time at sea, while waiting for the T23's and T45s to get through refits and repairs
Ummm, once again.
The 1st sea loads said, ‘I’m pleased to say we have two crews for the two carriers [and] it’s not at the expense of manning elsewhere in the fleet..

But, still, the facts are
- RN only mans 12 escorts (clear)
- 2 escorts are in extended readiness (or alike) because of man-power shortage (this is also officially commented)
- (and remaining 5 is in LIFEX or long maintenance)
- at the same time, trained personal (FTTS) number deficiency has been INCREASED from Jan 2019 to July 2019. Now it is 1500 soul shortage, as of July 2019. (*1).
If we read this fact along with the 1st sea loads comment, it just means, RN thinks only 12 escort crewed is OK.

Then there is no need for "19 escorts", I'm afraid.. At least, the 2 escorts in extended readiness is completely useless.

I rather think, still the man-power shortage is significant, and RN are FORCED to go along with "only 12 manned", and are not happy with it. So, it is not the crew is waiting for escorts, but escorts are waiting for (trained) crew, still. I cannot understand why you think the other way... Sorry...

*1 ref :https://assets.publishing.service.gov.u ... 7-_SPS.pdf

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Re: Current & Future Escorts - General Discussion

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Looking at the new French FDI (Defense and Intervention Frigate) following the steel-cutting ceremony of the first ship October 24th., previously the FTI (Frégates de taille intermédiaire).

Uses an unusual type of hull design, shades of Zumwalt, inverted bows to maximise the length of waterline and hence the hull speed to give lower hydrodynamic drag than ordinary bows, drawback reduced reserve buoyancy and may dive under waves instead of piercing or over them. 4,500t; 121.6 m x 17 m; CODAD 4x 8 MW MTU 16V 8000 M91L; ~27/29 knots; 5,000 nm @ 15 knots; 125 crew plus accommodation for additional 28 eg special forces, approx €3.8 billion budget/£3,725 million, ~£650 million each

Main contract for the five frigates was signed April 2017 with the Naval Group and Thales France for the development of a new gen GaN four panel antenna S-band radar - SeaFire. May 2019, the final design frozen. September 2019 Thales started SeaFire testing on a Shore Integration Facility near Toulon. November the Naval Group Lorient will operate an integration platform to accelerate the development and validation of the ship’s IPMS (Integrated Platform Management System).

Design/build - Naval Group shipyard plan 30 month build per ship, using Dassault Systèmes 3D digital software to design the entire ship and its components, Microsoft HoloLens augmented reality glasses are used in Lorient’s shipyard to assist the installation of equipment on the ship. The first FDI will be delivered to the French Navy in late 2023, second one is set for delivery before the end of 2025 and the last three FDIs are due to be delivered before 2030

Integrated mast PSIM (Panoramic Sensors and Intelligence Module), integrates the SETIS CMS, CIC and most sensors. PSIM designed, produced and tested in parallel to the ship’s platform, facilitating the tests on the CMS, the crew training and the integration on the platform, the PSIM separate development to reduce build by 10 to 12 months.
The four AESA panels of the SeaFire 500 radar with the IFF.
Two Safran PASEO-XLR for long range day/night passive IR detection and identification
A 360° short range camera control system by Bertin Technologies,
A suite of digital C-ESM and R-ESM 
The CIC fully integrated inside the module, allowing full scale training with an operational combat system before integration of the PSIM on the ship’s hull,
One of the two Data-Centers also be integrated in the PSIM, the other one being placed in the hull aft.

The new SeaFire radar integrated in the PSIM will offer a 360° constant monitoring and tracking ability against high velocity and low RCS air and surface targets. SeaFire 500 can track up to 800 objects at a range of up to 500km for aerial targets and 80km on the surface. 

SETIS CMS, the computer/IT servers can be updated without changes to the software, software updates and can add new functionality through applications, similarly to a mobile phone.

The Thales AQUILON advanced communication system, integrated communication system provides a full shipboard and external voice and data communication capability (HF, VHF, UHF and satcom). 

ASW - HMS KingKlip Mk.2 ; VDS CAPTAS 4 compact/light; 2×2 MU-90 LWT, two on each side, CANTO anti-torpedo decoys
AAW 16 Aster 15 or Aster 30 missiles in 2x 8 A50 VLS cells
AShM 8 Exocet MM-40 Block 3C missiles
Leonardo 76mm MG, FCS Thales STIR EO Mk.2 both radar and electro-optic tracking systems, able to fire the guided DART round for AA.
Two Narwhal 20mm guns in RWS
11t helicopter and UAV
Two ECUME RHIBs
Two Sylena Mk2 decoy launchers

Design for export allows for an additional hull module of up to 9m in mid-ships to accommodate additional 16 VLS cells, more powerful engines, fuel, larger facilities for special forces, UUW systems etc., main gun could be swapped for a 57 or 127mm and a CIWS, Oerlikon Millennium 35mm /RAM fitted to top of the helicopter hangar.

Looks like a smaller Iver Huitfeldt class frigate at approx twice the cost, appears high cost driven by having ~ 90+% French content, build time of 2 and a half years, fully equipped GP frigate with AAW, AShM though its ASW ops limited by its noisy CODAD, reinforces my view that the T31 as currently funded/spec'd is a long range OPV.

From <https://www.navalnews.com/naval-news/20 ... i-frigate/>

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Re: Current & Future Escorts - General Discussion

Post by donald_of_tokyo »

NickC wrote:Looking at the new French FDI (Defense and Intervention Frigate) following the steel-cutting ceremony of the first ship October 24th., previously the FTI (Frégates de taille intermédiaire).
...
Leonardo 76mm MG, FCS Thales STIR EO Mk.2 both radar and electro-optic tracking systems, able to fire the guided DART round for AA.
Thanks!
By the way, are the 76mm gun of FDI, DART capable? At least, not written in the original article, I think? I understand DART need special turret with line-of-sight guidance radar to be adopted, with different shape from those adopted on French navies' ships.

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Re: Current & Future Escorts - General Discussion

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SD67 wrote: this is always going to be difficult for a democratic government unless there’s a bipartisan national consensus on defence. We don’t have that in the UK so there always going to be a juggling act. In fact very few democracies outside the US have that - Australia, and who else?
Denmark, Sweden is now working to get there, S. Korea (ROK). Finland has a particular form of it: There is concensus for retaining the 1.6% of the GDP expenditure level or so, but the so called Strat. Projects (AF 60 or so fighters and Navy 4 corvettes/ light frigates that breach the convention that Blue Water - er, the Baltic is never blue - operations are unaffordable) will push the envelope to 2% for half a decade
- so DK + SF for 5 yrs
- ROK + SW for the length of parliament (in Sweden that has not been v long lately, so there must be some "small print" which I have not seen, to allow for that)
Ever-lasting truths: Multi-year budgets/ planning by necessity have to address the painful questions; more often than not the Either-Or prevails over Both-And.
If everyone is thinking the same, then someone is not thinking (attributed to Patton)

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Re: Current & Future Escorts - General Discussion

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NickC wrote:The first FDI will be delivered to the French Navy in late 2023, second one is set for delivery before the end of 2025 and the last three FDIs are due to be delivered before 2030
Under 9 mths per ship, but factor in 35% concurrency and you get 13 mth build time. Even though:
NickC wrote:high cost driven by having ~ 90+% French content, build time of 2 and a half years
would indicate a lot going on for many hulls before 2023; when the first will be hitting the water ?

- what was it that we are hearing for the T31s?
Ever-lasting truths: Multi-year budgets/ planning by necessity have to address the painful questions; more often than not the Either-Or prevails over Both-And.
If everyone is thinking the same, then someone is not thinking (attributed to Patton)

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Re: Current & Future Escorts - General Discussion

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donald_of_tokyo wrote:Re: Current & Future Escorts - General Discussion
Unread postby donald_of_tokyo » 04 Nov 2019, 16:13

NickC wrote:
Looking at the new French FDI (Defense and Intervention Frigate) following the steel-cutting ceremony of the first ship October 24th., previously the FTI (Frégates de taille intermédiaire).
...
Leonardo 76mm MG, FCS Thales STIR EO Mk.2 both radar and electro-optic tracking systems, able to fire the guided DART round for AA.
Thanks!
By the way, are the 76mm gun of FDI, DART capable? At least, not written in the original article, I think? I understand DART need special turret with line-of-sight guidance radar to be adopted, with different shape from those adopted on French navies' ships.
Good point, it was my assumption as you noted not stated in NavalNews. The Thales FCR STIR EO Mk.2 radar and electro-optic tracking systems was quoted as fitted specifically to control the gun and would think be more than capable of controlling the DART, replacing the Leonardo on mount tracking/guidance radar, my assumption Thales have contract control of all electronic weapon systems fitted to the FDI, as T31, they would substitute their kit wherever possible, in this case Leonardo's ?


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Re: Current & Future Escorts - General Discussion

Post by Ron5 »

Not the only personal assumption that crept into that comment.

e.g. the Sea Axe bow. Not for speed but for sea keeping.

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Re: Current & Future Escorts - General Discussion

Post by SD67 »

[quote="donald_of_tokyo"][quote="Caribbean"]

I rather think, still the man-power shortage is significant, and RN are FORCED to go along with "only 12 manned", and are not happy with it. So, it is not the crew is waiting for escorts, but escorts are waiting for (trained) crew, still. I cannot understand why you think the other way... Sorry...


I think we’re over-analysing this a bit. Manpower and equipment are often two sides of the same coin. When there’s brand new slick kit to be mastered the manpower will materialise. When it’s obsolete clapped out and malfunctioning the manpower has a habit of finding more important things to do. Build it and they will come.

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Re: Current & Future Escorts - General Discussion

Post by NickC »

Ron5 wrote:Not the only personal assumption that crept into that comment.

e.g. the Sea Axe bow. Not for speed but for sea keeping.
The Sea Axe bow design different in concept and shape, developed by Damen and Delft University

The French bow for the FDI different shape as shown in the NavyRecognition/Xav Aug 2017 video 2:20
FTI Frigate Hydrodynamic Test by DGA French Procurement Agency



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Re: Current & Future Escorts - General Discussion

Post by Ron5 »

Still not for speed dude. RCS reduction, seakeeping or looks: take your pick.

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Re: Current & Future Escorts - General Discussion

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Ron5 wrote:Still not for speed dude. RCS reduction, seakeeping or looks: take your pick.
Are you sure, the Sea Axe bow you quoted is designed for speed, the Associate Professor at the Delft University, Lex Keuning, explicity states he designed the new type of hull with the Sea Axe bow built to withstand more speed and Damen holds the exclusive license on the patent and developed the Sea Axe Patrol Vessels and Fast Crew Suppliers with great success.

"Keuning concluded that the removal of flare, the minimisation of the V-shape of the bow and a deeper keel line sufficiently reduced the pounding movement of a ship. However, because of the removal of flare and the minimisation of the V-shape, the bow loses a lot of ‘volume.’ This volume is nonetheless crucial to keep the front of the ship above the water. As a solution, Keuning added extra buoyancy. As a result, the shape of the bow became similar to an axe bow. Thus, the ‘axe bow’ was born.

At the beginning of this century, they worked together with the Royal Navy, Maritime Research Institute Netherlands (MARIN) and the US Coast Guard to investigate the axe bow as a new type of hull. Keuning’s earlier research was also confirmed by the outcome of these investigations. Due to the application of the axe bow, the number of peak accelerations was decreased by 80 per cent, and as a bonus, the axe bow also contributed to 10 to 20 per cent fuel use reduction."

Re. my post the bow designed for the French FDI is totally different in design and concept to the Sea Axe ,Keuning "the bow loses a lot of ‘volume.’ This volume is nonetheless crucial to keep the front of the ship above the water. As a solution added extra buoyancy". The shape of the FDI inverted bow shape losses buoyancy in heavy seas when underwater when you most need it, that's why questioned design, similar in shape to Zumwalt bow but the 16,000t Zumwalt fitted with large counter flooding tanks to ensure it remains stable.

From <https://worldmaritimenews.com/archives/ ... ty-at-sea/>

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Re: Current & Future Escorts - General Discussion

Post by MikeKiloPapa »

NickC wrote:
Looks like a smaller Iver Huitfeldt class frigate at approx twice the cost, appears high cost driven by having ~ 90+% French content, build time of 2 and a half years, fully equipped GP frigate with AAW, AShM though its ASW ops limited by its noisy CODAD, reinforces my view that the T31 as currently funded/spec'd is a long range OPV.
From <https://www.navalnews.com/naval-news/20 ... i-frigate/>
Excuse me, i dont mean to sound flippant , but how do you know that it's noisy?.....do you have a recording of its underwater signature?...well of course not because it doesn't exist yet, but how about a similar(ish) vessel with an equivalent propulsion setup ....like for instance the Iver Huitfeldt you mention yourself above ? .....Probably not though right.....

Im willing to bet dollars to doughnuts that most if not all those banging on about "quiet this, noisy that" in relation to warships have never even heard another ship under water through hydrophones....yet act as if they were experts and summarily declares a ship unfit for ASW just based on a few paper stats....and it simply doesn't work that way irl.

Signature management and sound profiles isnt all or nothing.....just because a ship isnt the most quiet of all the quietest ships to graduate from the University of Silence ;) doesn't mean that its useless at ASW. Just like a T23 wont suddenly become less capable just because its successor will (presumably) be even quieter.

Yes , an IH or the future FDI will not be as silent as a T23, T26, or FREMM but it might well be just as or more quiet than everything else out there. Even a pure diesel driven vessel can be effective at ASW, especially in the right environment and as part of a larger ASW force.
With the right hull, right machinery and especially the right propellers operated in ASW mode (high pitch low RPMs) a direct drive diesel can be surprisingly silent , and if you add a capable HMS, a VDS/TASS and an Merlin HM2 to the T31 you will get a warship every bit as capable at ASW as the T26 will be at air defence,if not more so.

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Re: Current & Future Escorts - General Discussion

Post by donald_of_tokyo »

Just a matter of how strong you say, I guess. I think both of your are correct in some sense.

"Trade off between silent hull with small sonar (presumably CAPTAS-2) vs noisy (or less silent) hull with large sonar (presumably CAPTAS4), and selecting the latter" is the official statement of Naval guy in the interview when FTI idea came about.

This means, FDI is noisier than FREMM.

Also it suggests, CODAD FTI with CAPTAS-4 is "better" than CODELAG FTI with CAPTAS-2" (but I guess it may include cost difference, for example 5 hulls vs 4 hulls).

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Re: Current & Future Escorts - General Discussion

Post by Lord Jim »

If ASW was dependant on the all or nothing quietening of ships then the USN would be out of the ASW game with the exception of its SSN force, and wasted millions on giving its surface vessels any form of sonar, let alone fitting them with ASROC. :D

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Re: Current & Future Escorts - General Discussion

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MikeKiloPapa wrote:
NickC wrote:
Looks like a smaller Iver Huitfeldt class frigate at approx twice the cost, appears high cost driven by having ~ 90+% French content, build time of 2 and a half years, fully equipped GP frigate with AAW, AShM though its ASW ops limited by its noisy CODAD, reinforces my view that the T31 as currently funded/spec'd is a long range OPV.
From <https://www.navalnews.com/naval-news/20 ... i-frigate/>
Excuse me, i dont mean to sound flippant , but how do you know that it's noisy?.....do you have a recording of its underwater signature?...well of course not because it doesn't exist yet, but how about a similar(ish) vessel with an equivalent propulsion setup ....like for instance the Iver Huitfeldt you mention yourself above ? .....Probably not though right.....

Im willing to bet dollars to doughnuts that most if not all those banging on about "quiet this, noisy that" in relation to warships have never even heard another ship under water through hydrophones....yet act as if they were experts and summarily declares a ship unfit for ASW just based on a few paper stats....and it simply doesn't work that way irl.

Signature management and sound profiles isnt all or nothing.....just because a ship isnt the most quiet of all the quietest ships to graduate from the University of Silence ;) doesn't mean that its useless at ASW. Just like a T23 wont suddenly become less capable just because its successor will (presumably) be even quieter.

Yes , an IH or the future FDI will not be as silent as a T23, T26, or FREMM but it might well be just as or more quiet than everything else out there. Even a pure diesel driven vessel can be effective at ASW, especially in the right environment and as part of a larger ASW force.
With the right hull, right machinery and especially the right propellers operated in ASW mode (high pitch low RPMs) a direct drive diesel can be surprisingly silent , and if you add a capable HMS, a VDS/TASS and an Merlin HM2 to the T31 you will get a warship every bit as capable at ASW as the T26 will be at air defence,if not more so.
My thoughts
Submarines are becoming harder to detect in the noisy environment of the sea, the new gen subs are fitted with sound absorbing anechoic coatings, perforated rubber tiles about 1 inch thick, and with a shrouded propulsor to reduce self generated noise (some pics of newer subs the stern is covered up in plastic sheeting to hide the shrouded propulsor design). Several areas of future research ongoing to make subs harder to detect, one French for a new generation of stealth coatings to replace anechoic tiles with ~4 mm silicone rubber coating with 2mm bubbles that could absorb more than 99 percent of the energy from sonar, cutting down reflected sound waves by more than 10,000-fold, or about 100 times better than was previously assumed possible (empty spaces, bubbles, in an elastic material when hit by sound waves can oscillate in size to dissipate the energy).

Self generated noise from ship will seriously degrade the sonar signal, either passive or active, was mentioned a T26 would need to stand off 100 miles from carrier to be fully effective?

Quiet ASW frigates cost, but can make the difference between detection or acoustic invisibility of sub.

Hybrid Electric Power, HED, diesel gens powering prop shaft electric motors and drives, both specifically designed for quietness eg T26/IT FREMM, and not powering shaft with electric motor/diesel via a noisy gearbox (gearboxes introduce tooth contact noise at a frequency which may easily propagate through the propeller shaft to the propeller and provide a source of underwater radiated noise, flexible shaft couplings can be used to mitigate).

Classic silencing of the diesel engines and generators on double-resilient mounting with acoustic enclosure. Full acoustic genset enclosures, from memory MTU offer four variants I'm sure with increasing cost, will effectively eliminate airborne flanking noise, however, full enclosures entail weight, space, and maintenance impacts. (One of the newer options is active mountings of a vibration absorbing mount fixed to a solid box containing vibration sensors and force actuators. The inputs are fed to a control unit and using control algorithms are analyzed and an appropriate signal is generated and fed back to the mount actuators resulting in a net decrease in noise and vibration).

A cheaper option is the corvette design by Fincantieri for Abu Dhabi designed a single-resilient mountings with proper associated rigidity, reduction gears are rigidly mounted on foundations carefully treated by means of appropriate viscoelastic materials and doubling plates, aimed to dampen frequencies considered critical to the sonar’s performance.

Propellers are very important for vessel efficiency, but big source of underwater noise, ASW frigate designers seek to move the thrust generated by the propeller tip closer to the hub, as unloading the propeller tip decreases the noise disturbance of the water/cavitation by the propeller, but can reduce its efficiency. Type 26 uses an optimised FFP for this reason, whilst FREMM uses a CPP, as always a trade off as though FPP will be quieter at low ASW speeds, its less efficient than a CPP at higher speeds, lowers max speed.

The T26 hull undergwent extensive model testing in hydrodynamic tanks, optimised for lower noise not speed.

A less costly option is the diesel corvette design by Fincantieri for Abu Dhabi designed a single-resilient mountings with proper associated rigidity, reduction gears are rigidly mounted on foundations carefully treated by means of appropriate viscoelastic materials and doubling plates, aimed to dampen frequencies considered critical to the sonar’s performance.

None of the above hardware is mentioned in the PR for the FDI, even the less costly option taken with the Fincantieri corvette, FDI was previously called FTI - 'intermediate' as not a full fat FREMM, so think my comment the FDI ASW ops is limited by its noisy CODAD is fair.

PS Think the advertised sonar manufacturers spec is based on transmit frequencies, theoretical propagation losses, theoretical target strengths v aspect, transmit source level, receiver array size, theoretical reverberation v time.
Actual performance underwater is more complex and operates to reduce performance and results in uncertainty due to the complexity of sonar signature propagation path structure to and from the target, degraded by variations over time due to small changes in sonar and target bottom depths and range plus clutter, bottom and surface reflections, are time varying causing high false alarm rates if the detection threshold is set too low, if too high will not detect sub. For understandable reasons navies give little discloser of the actual results of trials, so that's a big unknown how effective sonar is and at what range in both blue water and littorals to be able to detect the new gen subs.

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ArmChairCivvy
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Re: Current & Future Escorts - General Discussion

Post by ArmChairCivvy »

NickC wrote:unloading the propeller tip decreases the noise disturbance of the water/cavitation by the propeller, but can reduce its efficiency. Type 26 uses an optimised FFP for this reason, whilst FREMM uses a CPP, as always a trade off as though FPP will be quieter at low ASW speeds, its less efficient than a CPP at higher speeds, lowers max speed.
These terms (abbreviations) throw me 'off the scent' as I am trying to look for
"F" as in fixed
and
"V" as in variable

I buy the argument, no probs.
Ever-lasting truths: Multi-year budgets/ planning by necessity have to address the painful questions; more often than not the Either-Or prevails over Both-And.
If everyone is thinking the same, then someone is not thinking (attributed to Patton)

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