Current & Future Escorts - General Discussion

[RetroSicotte]

I propose cutting the third FSS and equipping the last three T31's with whichever sonar is most appropriate with the funds available, and try and retrofit the other later on.

To be honest, I think the third SSS is likely already "used" funding wise for the LSS.

Not that it devalues your point on preference for what money should go into. Just SSS no. 3 being an easy source I think may be past now.

[ArmChairCivvy]

I think the third SSS is likely already "used" funding wise for the LSS.

Not that it devalues your point on preference for what money should go into. Just SSS no. 3 being an easy source I think may be past now.

I think the 2+1 (option) was worded in that way to see how much spare change would be left from the 1 bn, once the indicative build bids were in
- my guess: not much

[NickC]

Donald-san, thanks for info on Atlas and S2150

The Dutch Navy say they are only using active acoustic sonar detection, no reason given as why not using passive, new generation submarines too quiet? It seems Canadian Navy has followed same path with their CSC with same LFAPS VDS and HELRAS helicopter dipping sonar, though using the CH-148 Cyclone whereas Dutch use the NH90.

It raises question if there is to be an ASW T31 how to allocate its very limited budget, is it better spent on LFAPS type VDS and HELRAS/FLASH helicopter dipping sonar for a more effective system in the view of the Canadian and Dutch navies than full fat compact CAPTAS 4 independent tow or dependent tow with its S2087 passive sonar?

Advantages maybe with LFAPS its lighter weight as its fitted to 3,300t Dutch M class and less costly? than the new CAPTAS 4 compact is 20/25t and the dipping helicopter sonar may well be funded from separate budget than T31

Thanks. The Dutch solution includes TASS part, as clearly seen in your 1st photo (*1) a cable towed from the throat. To my understanding, a TASS added with low frequency pinger (either active-TASS or VDS fish) is the definition of Low Frequency Active Passive system.

*1 Ultra_Low_Fequency_Active_Passive_Sonar_LFAPS_HMAS_Van_Amstel_M_class_3300t.jpg

Not sure how frequently these LFAS systems do "passive" operations. But, Submarine technology has improved from 1990s.

- acoustic stealth has been introduced (shape of the hull) --> bi/multi-static to detect the "deflected" signal (the same path anti-radar stealth goes on).
- tiles/rubber to absorb sound wave --> low frequency (the same path anti-radar stealth goes on, as well).
- SSK and SSN get more and more quiet. To my understanding, if they are not "cruising", they are now as quiet as sea itself --> more stress on active sonar

I understand these situations are leading to "low frequency + multi-static" solutions. Sonobuoy operations are also going this way.

Passive would be used to
- not enable SSN's high-speed cruise
- not enable SSK's snorting (=needed for cruise)
which is still important but surely less so.

As you point out LFAPS can operate in both active and passive modes, the Dutch Navy / TNO NATO paper MP-SET-244-12A.pdf on the "Co-ordinated deployment of underwater sensors in underwater operations’ to make the best use of the effective and efficient deployment of LFAPS and HELRAS, it states" We only take active acoustic detection of the threat into account." TNO created A Priori Planning of ASW Operations software: Providing a Robust Mission Advice. The operational software mission advice provides the ASW commander with a set of alternative tactics that allows the ASW commander to select the best solution, based on his experience and his knowledge of the actual tactical situation.

Interesting paper on best use of ASW and if you a read would be interested your interpretation.

[shark bait]

To be honest, I think the third SSS is likely already "used" funding wise for the LSS.

That is likely, there was a comment a while back that the "exact mix has not yet been decided", perhaps this was referring to the LSS concept that was starting to emerge.

Contract is due to be signed in 2020, so we may see more details dripping through, but this is the British MOD so probably not.

[NickC]

Donaold-san

Forgot to mention in post #432 that the LFAPS processing software was developed by TNO, Netherlands Organisation for Applied Scientific Research, so they would be well versed in LFAPS VDS active and passive capabilities.

[donald_of_tokyo]

As you point out LFAPS can operate in both active and passive modes, the Dutch Navy / TNO NATO paper MP-SET-244-12A.pdf on the "Co-ordinated deployment of underwater sensors in underwater operations’ to make the best use of the effective and efficient deployment of LFAPS and HELRAS, it states" We only take active acoustic detection of the threat into account." TNO created A Priori Planning of ASW Operations software: Providing a Robust Mission Advice. The operational software mission advice provides the ASW commander with a set of alternative tactics that allows the ASW commander to select the best solution, based on his experience and his knowledge of the actual tactical situation.

Interesting paper on best use of ASW and if you a read would be interested your interpretation.

Thanks. First of all, I understand "active" for LFAPS, CAPTAS and ACTAS is, "pinging" from VDS fish and "listening" from passive-TASS. This is why I say both VDS fish and passive-TASS will be included in "active" LFAPS/CAPTAS/ACTAS operations.

This is from Japanese Ministry of Defense document. Here, pinger is either hull-sonar or VDS fish. But, VDS fish is NOT a listener. I do not know, but I think CAPTAS-4 VDS cannot listen, just pinging. (as you can see, the VDS fish in this graphic is very much CAPTAS-2 (or 4) like). All the other LFAS might be in the same mode?

multi-static.jpg

Donaold-san

Forgot to mention in post #432 that the LFAPS processing software was developed by TNO, Netherlands Organisation for Applied Scientific Research, so they would be well versed in LFAPS VDS active and passive capabilities.

So, "passive" operation is basically not efficient anymore, at least Dutch Navy thinks.

[Ron5]

If the submarine in your picture is an Astute, it will be passively listening and knows the location of all those surface ships.

[NickC]

Donald-san

My understanding is that Dutch and Canadian Navies think the single body LFAPS VDS and HELRAS dipping sonar in combination is very effective for the ASW operational missions they envisage eg area search to sanitise sea lanes to enable transit and barrier protection of high value units eg carriers/convoys.

The Canadians developed the hardware and the Dutch the software for LFAPS with the payback that they do not have to go to the cost of installing a large passive towed array sonar several miles long, if the system successful they bring down the SWaP-C, size, weight and power-cost, required for an ASW frigate, the Dutch Navy fitted to their M/Karel Doorman class frigates which only 3,300t.

[Lord Jim]

Not being an expert on ASW, is there a single system that can handle both deep water and littoral ASW operations against both Nuclear and conventional boats? How effective are the current generation of Helicopter dipping sonars in the littoral environment? I think we agree the T-26 is a world class ASW platform in deep water, how good do people think in will be in littoral areas?

[donald_of_tokyo]

If the submarine in your picture is an Astute, it will be passively listening and knows the location of all those surface ships.

Even if the two "listener ships" in back were T26? May be. Surface ship is not as quiet as the sea itself. SSK is (when in silent mode).

[donald_of_tokyo]

Donald-san

My understanding is that Dutch and Canadian Navies think the single body LFAPS VDS and HELRAS dipping sonar in combination is very effective for the ASW operational missions they envisage eg area search to sanitise sea lanes to enable transit and barrier protection of high value units eg carriers/convoys.

Interesting. Sorry but where can I find the source information? Anyway, then Dutch M-class and it's replacement, Canadian Halifax class and T26-RCN will not carry TASS in that case, which could be observable.

The Canadians developed the hardware and the Dutch the software for LFAPS with the payback that they do not have to go to the cost of installing a large passive towed array sonar several miles long, if the system successful they bring down the SWaP-C, size, weight and power-cost, required for an ASW frigate, the Dutch Navy fitted to their M/Karel Doorman class frigates which only 3,300t.

M-class frigate has TASS winch room from its design. They added VDS crane to the port side. The orientation the same to those adopted in T23ASW.

Similarly, RAN/RNZN ANZAC class (3600t FLD), and Portuguese Vasco da Gama class (3300t FLD) also had a TASS winch room. At least, those of RNZN Te Kaha/Te Mana was there until recently, but now it is reused for gim.

Also, even if called "TASS", its size differs a lot. For example, CAPTAS-4 has a big TASS winch, but that of CAPTAS-1 is very small. CAPTAS-1 can be carried in two 10ft ISO containers (or in a single 20-ft container), one for crane (+VDS fish) and the other for TASS winch. In case of ACTAS (Atlas), whole system can even deploy from ARCIMS 11.3m-long USV.

Photos; Dutch F831 Van Ness with Ultra LFAPS (both VDS and TASS) and RNZN Te Kaha stern with TASS throats (was for Kariwara TASS, which was abandoned "ANZAC" TASS project).

TASS.jpg

[Ron5]

If the submarine in your picture is an Astute, it will be passively listening and knows the location of all those surface ships.

Even if the two "listener ships" in back were T26? May be. Surface ship is not as quiet as the sea itself. SSK is (when in silent mode).

The hull mounted listening array on an Astute is massive, way more sensitive than any surface ship and, of course, it is mounted on a a very quiet platform.

An SSK sitting on the seabed maybe extremely quiet but once it starts moving, and it has to in blue water, then it makes noise.

Anyhoo, just making the point that passive ASW is still alive and kicking.

[dmereifield]

Its entirely feasible, and preferable to using a massive frigate for local patrols.

Don't we want our top end capability for that rather than using somwthingnthats just about "OK"?

[donald_of_tokyo]

The hull mounted listening array on an Astute is massive, way more sensitive than any surface ship and, of course, it is mounted on a a very quiet platform.
An SSK sitting on the seabed maybe extremely quiet but once it starts moving, and it has to in blue water, then it makes noise.
Anyhow, just making the point that passive ASW is still alive and kicking.

No big objection. And because of your point, if Netherland Navy is not going to adopt passive only operation, but only active LFAPS operations, it is very interesting.

For example, for CVTF inner-layer ASW, I think it is more and more active, not passible. Even in 1990s, SH60F helo was used with active dipping sonar, and not SH60B with sonobuoys in US Navy. Nowadays, SSK getting more quiet, while CVTF member ships getting more larger (CVTF, SSS, Tides ...) and thus inevitably noisy, I think passive is getting much less effective...

[shark bait]

Don't we want our top end capability for that rather than using somwthingnthats just about "OK"?

Are local surveillance patrols really the best use of the biggest and most capable and Frigate the RN ever had?

Not being an expert on ASW, is there a single system that can handle both deep water and littoral ASW operations against both Nuclear and conventional boats? How effective are the current generation of Helicopter dipping sonars in the littoral environment? I think we agree the T-26 is a world class ASW platform in deep water, how good do people think in will be in littoral areas?

There is no one size fits all, different systems will perform better in different environments. The Royal Navy need to operate in blue water and protect the carriers, the CAPTAS-4 equipped T26 is a product of that requirement.

Dipping sonar equipped helicopters are the king in the littorals, but I expect it's difficult to sustain.

The T23 regularly operates in the littorals, over the decades of operation the RN have worked out how to operate their sonars in shallower waters. If conditions allow, the variable depth sonar is able to penetrate the more condensed layers of water found in coastal regions, offering a big advantage, however the risk of damage to the fish is often too large. Because of that its not the optimal tool for the littoral environment but its still pretty good. Also it carries a Merlin = The King!

An SSK sitting on the seabed maybe extremely quiet but once it starts moving, and it has to in blue water, then it makes noise.

Anyhoo, just making the point that passive ASW is still alive and kicking.

An SSK sat in the open ocean would have to be very lucky to be threatening to a carrier group because they typically don't have the speed to intercept. The danger comes in more confined waters where the odds tip in the SSK favour. It is becoming increasingly accepted that active sonar is the most realistic way to monitor the threat.

Out in the open ocean all subs have to move faster to catch a carrier, thus becoming nosier increasing the chances of passive detection. So yeah, both methods are alive and kicking and will be applied as the environment dictates. The RN need to be experts at both.

[Tempest414]

Its entirely feasible, and preferable to using a massive frigate for local patrols.

Don't we want our top end capability for that rather than using somwthingnthats just about "OK"?

For me if we had 2 Leander's or A140's set up to cover TAPS only with a 57mm , 4 x 30mm , 12 CAMM , 8 cell Mk-41 VLS and CAPTAS-4CI working with a Merlin and a P-8 it could release 2 T26's back to full escort duties

[shark bait]

Something similar has potential to become a valuable addition to the fleet, it could be an answer to the "T26 is over specced for local patrols" argument. However it could be in danger of having a small operating profile, rarely does the enemy let you operate on your terms.

Incidentally the CAPTAS-4CI comes on a single skid that Thales has proposed sharing between hulls. Perhaps the two sets could be shared between the whole class as appropriate?

[Tempest414]

However it could be in danger of having a small operating profile,

Can I push to expand on this a bit more

[RetroSicotte]

However it could be in danger of having a small operating profile,

Can I push to expand on this a bit more

What I grasp he's meaning is that a low end escort purely for local peacetime ASW/patrol matters is essentially an escort lost if you need to do something outside that small envelope of operational capability when things get hot, or further afield.

[donald_of_tokyo]

But it is also with dilemma of losing numbers. Budget is limited, so with higher specification= you lose numbers, lower specification = you can build/operate more hulls. And, in some "hot" cases, number may be needed, and another "hot" case, higher specifications may be needed. Never ending story.

A tier-1 fleet of "6 T45 and 8 T26" added with tier-2 fleet of "5 T31", supported by tier-3 (or OPV) fleet of 5-9 River OPVs, are not so bad balance I think (*1).

T31 could be a simple ASW corvettes (if so, name them Flower-class, Castle-class or Blackwood-class), or simple GP light frigates (name them Tribal class or British La Fayette class ), but will not be capable of doing both.


*1 Simply because of "lack of man-power" issue, I am slightly shifted to "more tier-1 and less tier-2" fleet these days

[Clive F]

Would name them county's after the areas missed by T26, eg Devon, Lancashire, Hampshire, Nottinghamshire, Norfolk

[RetroSicotte]

Clearly that's the solution to both sections.

Just ask every county to make a T31. No cohesion, just make whatever they each individually want, and take their own county name.

Yes, even the landlocked ones.

Solves escort numbers and breaking monopoly in one go.

Can't see any issues at all.

[Tempest414]

What I grasp he's meaning is that a low end escort purely for local peacetime ASW/patrol matters is essentially an escort lost if you need to do something outside that small envelope of operational capability when things get hot, or further afield.

It could also be said that TAPS will always need to be covered so there for having 2 tier 2 ships tasked is the best out come plus a T-31 with a 57mm , 4 x 30mm , 12 CAMM , 8 cell Mk-41 VLS and CAPTAS-4CI is a step up from where we will be at this time

[dmereifield]

What I grasp he's meaning is that a low end escort purely for local peacetime ASW/patrol matters is essentially an escort lost if you need to do something outside that small envelope of operational capability when things get hot, or further afield.

It could also be said that TAPS will always need to be covered so there for having 2 tier 2 ships tasked is the best out come plus a T-31 with a 57mm , 4 x 30mm , 12 CAMM , 8 cell Mk-41 VLS and CAPTAS-4CI is a step up from where we will be at this time

T26 is over specced in many aspects for TAPS, but if the T31 can't locate, and evade, subs as accurately and efficiently as T26, then surely it's not a good idea to have T31s do the job

[Repulse]

The design, training and maintenance of a new class of 2 ships for a specific role such as TAPS, surely is a waste of money whereby you save little from buying 2 T26s (especially as BAE offered to build one for free).