The Ministry of Defence has placed a contract with Ultra Electronics for the provision of three Sonar 2170 ‘Surface Ship Torpedo Defence’ systems to be fitted to the Type 31 Frigate fleet.

Known as Sonar 270 in Royal Navy service, the United Kingdom Surface Ship Torpedo Defence (SSTD) system entered into service with the Royal Navy in 2004. The system is produced by Ultra Electronics and is known as Sea Sentor in the export market.

The system consists of

  • an acoustic passive towed array
  • a towed acoustic countermeasure (flexible)
  • a single-drum winch
  • a processing cabinet
  • 2 display consoles
  • 2 expendable acoustic device launchers (1 port, 1 starboard)
  • 16 expendable acoustic devices (8 in each launcher)

The contract notice states:

“Ship Acquisition, which is part of the UK Ministry of Defence (MOD) proposes to place a contract with Ultra Electronics Limited for the provision of three Sonar 2170 SSTD Fit-to-Receive (FTR) kits. The SSTD kits are to be integrated onto the Type 31 Frigates.

The equipment to be supplied is Fit-to-Receive kits for the Sonar 2170 SSTD which the MoD owns and utilises across UK MOD Platforms.

Therefore, it is a key requirement that it is interoperable with the existing Sonar 1270 SSTD currently utilised. Ultra Electronics Limited has been identified as the only supplier capable of fulfilling this requirement as they are the sole manufacturer of the FTR kits and are the sole supplier holding specific technical data required for the performance of the contract.”

The contract is valued at £600,000.

The rendering at the top of the article shows Type 31 employing its Sonar 2170 towed-body equipment.

George has a degree in Cyber Security from Glasgow Caledonian University and has a keen interest in naval and cyber security matters and has appeared on national radio and television to discuss current events. He also works for the NHS. George is on Twitter at @geoallison
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Blue Fuzz
Blue Fuzz
1 month ago

Three systems to be shared between 5 Type 31, or an additional 2 systems to be ordered later?

Rfn_Weston
Rfn_Weston
1 month ago
Reply to  Blue Fuzz

Take a wild guess. If they were ordering 5 sets at the cost it is, they would have ordered them if you ask me. They are a pathetic lot really.

Andy P
Andy P
1 month ago
Reply to  Rfn_Weston

I share your take on only ordering three, doesn’t leave much slack in the system does it.

Steve
Steve
1 month ago
Reply to  Andy P

I guess it depends how many will be operational at any one time. Considering the availability rate of the current frigates, 3 for 5 is probably enough. Admittedly in a war situation ships would be raced back into service and availability would increase.

Andy P
Andy P
1 month ago
Reply to  Steve

I get that mate but what happens if one of the sets goes ‘tits up’, then its 2 for the class of 5. I’ve no idea how robust the system is so maybe making too much of it.

Steve
Steve
1 month ago
Reply to  Andy P

Fair. I suspect if there was a war and the fleet was called into action they would discover that they could only equip a small number of the available vessels with the gear they need. For example CAMM, with it being used across all services, what’s the bets we only have enough for one to use them.

Ianbuk
Ianbuk
30 days ago
Reply to  Steve

Short-sighted economics could result in the loss of a ship. It’s outrageous to think they could even contemplate sharing three sets between five ships. The once-mighty Royal Navy is reduced to cannibalising one ship to put it on the ‘other ship’ that’s going out to sea next.

What next, one engine between two ships?, I mean, it’s not as if this island nation will ever need more than one unit to be at sea!

The politicians are as short-sighted as a Mole!

Posse Comitatus
Posse Comitatus
30 days ago
Reply to  Ianbuk

Ah yes, but you’re forgetting that these systems are ‘ more agile, more lethal ‘ so less numbers are required…….🙄

Jon
Jon
30 days ago
Reply to  Ianbuk

“Going out to sea next” is a very UK based picture. The Type 31s are expected to be forward based around the world. The cost of lugging the system from Asia to Africa to the Caribbean would be more than just buying two extra.

There’s something interim/stopgappy about this.

andy reeves
andy reeves
25 days ago
Reply to  Jon

always is

Andrew
Andrew
30 days ago
Reply to  Ianbuk

Ian…. My understanding is that the Royal Navy has been cannibalising it’s ships for years… harpoon, phalanx etc etc…
i’m sure someone in the know would be able to confirm that…

andy reeves
andy reeves
25 days ago
Reply to  Ianbuk

the R.N has been canibalising ships almost forever the crew(including me) used to pillage the decommssioned h.m.s lion there was so much of the lion robbed to tiger it was nicknamed the liger! later tiger was stripped of parts to keep hms blake going.

andy reeves
andy reeves
25 days ago
Reply to  Andy P

maybe if we said we’d use them for the t32 we’d get a discount for buying in bulk

Callum
Callum
1 month ago
Reply to  Rfn_Weston

Take a logical guess, its an existing system already in the fleet, and what is currently happening? Two T23s are going out of service and freeing up kit.

Is that definitely what’s happening? I don’t know, but it makes far more sense than a daft scenario where only 3 systems are being shared between 5 ships

Meirion X
Meirion X
30 days ago
Reply to  Callum

I think most likely. Three ships need to built first, by this time the dismantlers will have removed the existing sets on the first T23’s to be decommissioned.

Steve
Steve
30 days ago
Reply to  Callum

Could explain it, but I thought those t23s were being stripped of gear and used on the first two t26s

Dern
Dern
29 days ago
Reply to  Steve

Yes but there are 13 Type 23’s and only 8 Type 26’s.

Steve
Steve
29 days ago
Reply to  Dern

Could explain it, I would however expect at least some of them ships to be sold off with their equipment includes.

Callum
Callum
29 days ago
Reply to  Steve

The first 3 T26s are being built with entirely new equipment to avoid having to decommission too many frigates early just to get the new ones in the water.

At least, that was the original plan. We’ve had a couple of governments since then, chances are nobody remembers that.

expat
expat
30 days ago
Reply to  Callum

I believe so 16 appear to have been ordered back in 2004. But there was a earlier version 2070 which may also still be in service.

JamesF
JamesF
28 days ago
Reply to  Blue Fuzz

The plan with Type 31 is to order systems as close to the in service date as possible to make sure they are up to date – it’s a different procurement model to Type 26.

Quentin Drury
Quentin Drury
1 month ago

Is this system also on the two carriers already? I can imagine that there is probably a need for 4×2 for each carrier ?

Quentin D63
Quentin D63
1 month ago
Reply to  Quentin Drury

I think I’m getting my systems muddled up so ignore me on this one. But I do hope that the carriers have some hull based anti torpedo/decoy system.

ChariotRider
ChariotRider
1 month ago

This sounds like it is just the ‘mounting’ brackets’ for the system, so I am guessing that the actual system is to be ordered later or (more likely?) the MoD will make do with what is already has and share them around the fleet..?

On the plus side these ships will be capable of carrying some sort of ASW kit, even if it is only defensive in nature…

Cheers CR

Steve M
Steve M
1 month ago
Reply to  ChariotRider

should be std on all warships especially those deployed outside UK waters, would love to see Wildcats having secondary ASW capability sonabouys and torpedos would at least give T-45’s capability to kill/drive off an SSK enough to get clear

Steve
Steve
1 month ago
Reply to  Steve M

From what I read the issue with wildcat having ASW hunting capability is flight time with it installed. They just can’t be on station long enough to create an effective sonabouy net.

Steve M
Steve M
1 month ago
Reply to  Steve

the original Lynx could do 2 hrs at 20miles with dipping sonar, bouys weigh less so endurance would increase

Steve
Steve
1 month ago
Reply to  Steve M

Out of curiousity how does that compare to the merlin?

Steve M
Steve M
1 month ago
Reply to  Steve

All i can find is 5 hours endurance but it’s unspecific if as to what role (ASW/AEW/CFH) 5 hours flying at optimun cruise in AEW going to use lot less than hovering at 30′ while you drop sonar 600′ and listen for 10mins nor does it say at what range etc

Deep32
Deep32
30 days ago
Reply to  Steve

The S Korean navy doesn’t seem to think so, their Wildcats are fitted with a dipping sonar!!! Expect it’s probably got more to do with a lack of money, and or we are waiting for a rotorcraft type drone to come into service to take on this tasking. Although the Wildcat can still carry Stingrays, it needs the Merlin to direct it’s attack.

Jonathan
Jonathan
30 days ago
Reply to  Deep32

I an surprised they have not looked at a number of the wildcats having dipping sonar to be honest, with the loss of a number of Merlins to AEW work we could do with some more ASW small flights.

Deep32
Deep32
30 days ago
Reply to  Jonathan

Yes indeed , as we do not seem likely to increase our Merlin numbers, it is probably the most cost effective way of quickly increasing capability in this area.

Stephen Hamblen
Stephen Hamblen
28 days ago
Reply to  Deep32

Well……. apparently, the Type 32’s are to be built as basically a mothership for numerous autonomous assets ( which are in development and testing stage) for the ASW role so it would fill the gap which would allow Wildcats and/or Merlins to be used in the other role, AEW.
Had we had the capability to launch Carrier based fixed wing AEW like our American cousins, we would’ve had aircraft with a decent loitering time to perform the task but unfortunately we only have helicopters which have a much shorter range and much shorter “on task” loitering time.

Deep32
Deep32
27 days ago

Unfortunately people vastly overestimate what these drones will be able to do/achieve in a maritime setting. They will for the foreseeable future be restricted to slow speed ops. Whilst they will no doubt at some stage be able to detect a transiting SM, they won’t be able to trail it, they don’t have the speed or endurance for that, so will be limited in their effectiveness. They won’t be able to do what a manned SM or helicopter can do, they will be an aid in the ASW war. Having these drones will not alleviate the fact that we don’t… Read more »

Bloke down the pub
Bloke down the pub
1 month ago

Being based around a towed array presumably limits when the system can be in use?

Nigel Collins
Nigel Collins
1 month ago

Or, a large torpedo fitted with a towed array 😂

23 MAY 2022
UK XLUUV trials demonstrate towed array sonar deployment
“The UK Ministry of Defence (MoD) has successfully demonstrated the capability to deploy a thin-line towed array sonar from an extra-large uncrewed undersea vehicle (XLUUV).

The trials, held off Plymouth, UK, in the second quarter of 2022, involved the MSubs 9 m S201 XLUUV and SEA’s thin-line towed KraitArray sonar.”

https://www.janes.com/defence-news/news-detail/uk-xluuv-trials-demonstrate-towed-array-sonar-deployment

Spyinthesky
Spyinthesky
1 month ago
Reply to  Nigel Collins

I think un-crewed mini subs and/or drones are going to be one of the most important developments over the next decade and beyond. The potential is boundless especially in littoral areas but also in fleet operations and even specialist single ship operations (which I presume is being studied in respect of t32) all sorts of designs and concepts are going to be proposed operating in endless scenarios for defensive and increasingly offensive operations. Think I raised it before but a small stealthy underwater platform operated by Ukrainian forces in the Black Sea could be devastating to any surface vessel or… Read more »

Nigel Collins
Nigel Collins
1 month ago
Reply to  Spyinthesky

In short, the future and the smart way forward in contested areas like the Black Sea or the SCS. Far less risk to our manned ships and submarines which is why we need to invest in this type of technology going forward.

Monkey spanker
Monkey spanker
30 days ago
Reply to  Spyinthesky

My main worry with autonomous stuff is what happens when something breaks/over heats or what ever common situations that cause current ships to have to have crew on board. If engines and equipment could operate without human input for long periods why do ships still have engineering crew?

JOHNT
JOHNT
1 month ago

Hmm In all the specs for Type 31 I’ve seen I haven’t seen mention of so much as a Hull Sonar in their electronics fit. So with this system fitted will they be able to tell if they are under torpedo, but not hunt down the sub other with their own sonar apart from sending the helicopter in the general direction the torpedo is coming from?

DP
DP
1 month ago
Reply to  JOHNT

Hi JOHNT, this article seems to focus on a towed array system but have you seen reference to a hull mounted system as well? I’m no expert in any of this but assume a hull mounted system would come first, before a towed system, any ideas? That reference ‘Fit-to-Receive (FTR) kits’ sounds a little like ‘Fitted For Not With’ …. is this a new take on an old reference just to throw people off …. I wonder? 😆

donald_of_tokyo
donald_of_tokyo
1 month ago
Reply to  JOHNT

Sea Sentor towed array is for torpedo detection and identification. It is also coupled with noise generation tow body. The system are sometimes mounted even on RFA tankers, so it virtually the descendant of the NIXIE (or alike) systems. Independently, Sea Sentor has an option of deck mounted decoy dispenser, launching noise decoy around the ship. RFA vessels do no host this system. Improvement of Sea Sentor is, the system can identify enemy torpedo vector and location, provide the bridge/CIC with navigation advice to void the torpedo and locate the decoy, thus significantly increasing the survival probability. Very good kit.… Read more »

expat
expat
30 days ago

Do you know if the all 16 kits were ordered back in 2004?

Bringer of facts
Bringer of facts
1 month ago

I thought towed arrays were for sub-hunting rather than defense ?

GlynH
GlynH
1 month ago

Towed arrays are for listening to anything underwater. Low frequency units listen for subs. Higher frequency units listen for torpedoes. Most subs (and ASW ships) have both. The low frequency one is usually much larger.

Bringer of facts
Bringer of facts
1 month ago
Reply to  GlynH

Yes, but surely you do not want the array to be deployed all the time ? , would hull-mounted sonar suffice here?

Rudeboy
Rudeboy
30 days ago

No, not for localising the threat and deploying countermeasures etc.

Deep32
Deep32
30 days ago
Reply to  GlynH

Our SMs only carry one towed array, with a frequency response that covers what you are alluding too. What the operators are looking/listening for is the fast rotational rate of its propellers or the whine of its propulsor, depending on it’s propulsion method. Alternatively, you would be looking for the weapon going active too, as it tries to get a range and bearing of its target.

Monkey spanker
Monkey spanker
30 days ago
Reply to  Deep32

Do the subs have a towed array in a drum that reel it in and out or is it hooked on at the start and taken off at end of deployments

Last edited 30 days ago by Monkey spanker
Deep32
Deep32
30 days ago
Reply to  Monkey spanker

A bit of both, the tow cable sits on a drum type arrangement, which is the reelable bit. The actual TA is fitted as the SM deploys and recovered when it returns. The TA is far thicker in diameter then the tow cable it is attached to and cannot be reeled in like the towed cable.

Monkey spanker
Monkey spanker
30 days ago
Reply to  Deep32

Ahh that makes sense. I remember the victor subs having the big towed array on the back and there being talks of it maybe being secret propulsion pod. But no it’s a towed array. (Or maybe that was in a movie)😂😂😂😂

Monkey spanker
Monkey spanker
30 days ago
Reply to  Deep32

Did you see the youtube the sub brief channel made about the Sea wolf class sub that crashed in South China Sea. The report got released and he breaks it down. Very close to losing the whole boat. Negative buoyancy even after emergency blow, a fire, propulsion off line and still sinking. Very lucky indeed. Worth a watch
https://youtu.be/IPr7Yrwgly4

Deep32
Deep32
30 days ago
Reply to  Monkey spanker

👍

Marked
Marked
30 days ago

Surely if they need torpedo defence then they need the systems to identify and kill the torpedo launcher, preferably before it can even launch an attack!

Without, sorry, its just a stay of execution. Or time for the crew to kiss their arse goodbye.

David
David
30 days ago
Reply to  Marked

I can’t think of an opponent that possesses complex subs that we might fight alone, and if we did fight alone, 3 SSNs, , 4-5 type 23/26 and a carrier with Merlin could handle them. That set of assets would beat most of the globe. We aren’t taking on China or Russia alone, if indeed a war ever kicks off. So I am not too concerned that every ship in the fleet isn’t a £1b vessel. Drones are being deployed by Hamas, the Houtis etc, its probably only a matter of time that they try and use rudimentary torpedos from… Read more »

Ianbuk
Ianbuk
30 days ago
Reply to  David

Let’s face it, the Royal Navy used Coastal Motor Boat‘s as far back as 1910. If Hamas, Houtis or any other small enemy doesn’t have the nowse in 2022 and use a speedboat with cheap torpedo launched at close range at night, it would be surprising. The USS Cole attack was a speed boat loaded full of C4

All the more reason for point defence capability.

Jonathan
Jonathan
30 days ago
Reply to  Marked

If they have a Merlin on board then the sub will be spending all it’s time evading the Merlin.

you have to remember these ships are going to be spending a lot of time in enclosed and busy waters where a tail may not be the ideal solution. Fingers crossed they will get an active sonar, paired with a Merlin that will make the a reasonable ASW threat.

AlexS
AlexS
30 days ago
Reply to  Jonathan

A Merlin can’t stay 24h flying.

Jonathan
Jonathan
30 days ago
Reply to  AlexS

Very true, but I was answering a question about a known threat. The simple truth is there are very few ships that can do anything about a submarine that they don’t know about. Even the best ASW ships in the world actually need to be trying to find a sub. A non specialist ASW ship has no real hope of detecting a submarine speculatively.the submarine alway generally has the advantage of initiative especially against lone ships even lone ASW ships if they are not engaged in looking for a sub.

Steve
Steve
28 days ago
Reply to  Jonathan

We saw this in practice in the falklands, the argentina ww2 era sub was able to evade detection and if it wasn’t for faulty torpedoes would have done serious dmg and that was with way more sub hunters than we currently have across the whole navy, which realistically could never be deployed all at the same time..

Last edited 28 days ago by Steve
John Hartley
John Hartley
30 days ago

Better not sell off Ultra to US corporate raiders then.

Tomartyr
Tomartyr
30 days ago

It’s starting to sound like they actually intend to take them to war..

AV
AV
30 days ago

I got all excited for a moment…thinking the 31’s were getting towed arrays!….(as in anti sub)..
Hey ho only actually anti torpedo lol…
Not to worry as wasnt aware they were even getting these.

Monkey spanker
Monkey spanker
30 days ago
Reply to  AV

Haha wait until you figure it out it’s only for the fixtures not the actual devices😱

AV
AV
30 days ago
Reply to  Monkey spanker

Yes worked it out now lol….got all excited by the title….should know better by now 👍

Monkey spanker
Monkey spanker
30 days ago
Reply to  AV

Me too. Until I started thinking 600k seems really cheap for 3 systems. I’m guessing the navy must have 2 sitting spare as to not put the fittings on all five when it’s 200k each would be madness

Steve
Steve
30 days ago

On a positive, until this post it was looking like the t31 wouldnt have any form of sub surface capability. Now let’s hear details of the missile fit out, really odd that the details are still not official.

Rob N
Rob N
28 days ago

Good news it is good to see it will get some subsurface protection.

Gunbuster
Gunbuster
28 days ago

The system is fitted to RN/RFA vessels as required if they are doing deployments in threat areas. It is very, very good at what it does. It detects incoming torpedoes, warns the crew, suggests a torpedo evasion course, launches decoys and does other “stuff” at the wet end to make the torpedo miss. Its not an ASW tail , its far to small for that, but it does show basic acoustic data on a display and if you know what you are doing and looking for you can see some specific frequency’s that subs and surface ships emit. Funnily enough… Read more »