Take a trip to the Firth of Clyde and you’ll sometimes notice a Type 23 Frigate sailing in the area, but why?

Much of the time, there is a very specific reason with the vessel having a very specific function, Towed Array Patrol Ship.

The primary purpose of the Towed Array Patrol Ship (TAPS) is to watch for submarine activity, especially around HMNB Clyde which is the home of the UK’s nuclear deterrent.

Simply put, TAPS is a standing Royal Navy task to provide anti-submarine patrol duties in support of the Vanguard class nuclear submarines that are responsible for delivering Trident nuclear missiles.


A Type 23 frigate is maintained at high readiness for this task 365 days a year and can typically be found, as said above, around or near the west coast of Scotland.

Type 23 Frigates provide the towed array patrol ship for reactive anti-submarine patrol duties in support of the strategic nuclear deterrent.

To perform this task, a portion of the Type 23 Frigate fleet carry Sonar 2087. The system is described by its manufacturer as “a towed-array system that enables Type 23 frigates to hunt the latest submarines at considerable distances and locate them beyond the range at which they can launch an attack.”

The system was fitted to eight Type 23 frigates between 2004 and 2012; the five oldest Type 23 frigates, HMS Montrose, Monmouth, Iron Duke, Lancaster and Argyll are not scheduled to receive Sonar 2087 and are considered more ‘general purpose’ vessels and will be replaced by the Type 31e where as the eight towed array equipped ships will be replaced like for like by eight Type 26 Frigates.

A frigate is maintained at high readiness for this task 365 days a year.

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If the RN always needs a ship ready for this then why not have a dedicated hull for this purpose fitted with the towed array and some anti-sub weapons, but without a main gun and sea ceptor and all the other paraphernalia that goes with a high end fighty ship? Seems to me like a waste of an escort, unless I am misunderstanding where these patrols operate.


That was the original plan for the T23’s with them originally only being equipped with sonar and a helicopter to attack the submarine with. They would operate in groups of 4 and self defence weapons (Sea Wolf) would be carried by a Fort Victoria ‘mothership’. However lessons from the Falklands war meant that the design evolved into the more general purpose as well as anti submarine design that we see today with weapons added on and the ship increased in size.

patrolling? listening? its a task a towed array fitted opv could do, weaponry carried or not,would depend on the remits of the task as they would be laid out but asw weaponry in containerised fashion could be mounted without too much difficulty, as could the towed array itself.

Geospectrum produce this for the Canadian Navy which can be carried by an OPV or even a vessel such as an oil rig support vessel. In the confined waters of the Forth of Clyde is 2087 OTT?

Better make that the Firth of Clyde.

ideal upgrade for the rivers can we get a containerised asw weapon in a crate?

The Norwegians have already experimented with the integration of STUFT into their exercises.


Rotation I’d guess, crew and ship. Cheaper to have the “full” T23 / T26, rather than have 3 specialist ones (RN rule of 3).

Cam Hunter

Should be based at faslane

No real need really.


Um no. Actually a ship is maintained there to repress the local Scottish Nationalists as we all know. Come on UKDJ, stop trying to pull the wool over our eyes with your dirty Westminster, Unionist agenda.

everything to do with the SNP is a smoke and mirrors game.the issue is far more sinister than we know about.and keeping them at bayaand again pushing their nationalistic manifesto again



Not to mention the targetting of the standby boat …

Don’t know where you got that from, perhaps to out your Scottish nationalist fears to rest we should close the navel base at faslane and take UK military ship building away from the Clyde, you cannot have things both ways, can you?


Has to be troll like behaviour and comment, as surely no real person with even a mediocre of a brain cell really thinks like that!


It was a joke Airborne, whichever of us it was you mean.

At least, I think it was …


Crap yes, have read it a few times it was a tongue in cheek bit of baiting….i need to go and dip my head in the bucket of humour. Cheers dads.

John Clark

I think 8 ASW frigates simply isn’t enough, with the rising submarine threat in the world today and the RN’ s future requirement to protect our new world wide trade deals.

We originally had 16 T23’s, configured for ASW and we need 16 T26’s in full anti submarine fit, in my opinion.

Mix in 10 Arrowhead T31’s for general duties and upgrade T45’s with quad packed Seaceptor and Astor NG (90 plus missiles) and we are getting to where we need to be regarding the escort fleet.

an old chestnut to me but, with pakistan retiring its 6 ex royal navy type 21’s, maybe a quick swoop by H.M.G could see them bought back for peanuts, refitted with latest towed array, ceptor, and asw weapons could see a useful stopgap while, ‘jock weers mae spannah gun tae? actually pulls his finger out and gets a ship built. old hulls or not . i think 6 ALREADY BUILT, ORIGIONALLY HIGHLY EFFECTIVE ASW FRIGATES, would be wellcomed at the admiralty, maybe the transfer of the first retiring type 23 would pay for them bringing the active fleet above the… Read more »

The Type 21 was never a “highly effective ASW frigate”, it was a very lightly armed general purpose design that lacked sufficient upgrade margin 40 years ago, let alone now.

Buying cramped, obsolete, worn out old frigates with high crew requirements is the opposite of what the RN needs to be doing. Focus should instead be on procuring a modest budget increase that is then reinvested in domestic industry building modern, cost-effective platforms to supplement the first rates we already own.


I was on a an ex T21 a few weeks ago. In engineering terms…its F*****

Harry Nelson

I was on a T21 in the 90’s, it was f*$ked then…….

the t21 i was on(avenger) was a fabulous ship and very good at its asw tasking, up to date fittings would make them well suited to today’s needs especially in the gulf.

never an effective asw ship? where do you get that from?(utter tosh!, the 21 was a great design and was ‘lightly armed as the result like always cost and political support. the excellence of the lynx more than made up for not having more weapons on the hull.

The T21 had no towed array and lacked the upgrade margin to have a modern hull sonar fitted in the 70’s. Its only defensive armament were some old decoys and near obsolete Sea Cat. Their aluminium superstructures were fragile and the hull needed reinforcement.

You have my utmost respect for your service Andy, but the T21 was a heavily flawed design. Fast and good looking, but flawed and vulnerable. You’re suffering from a case of rose tinted glasses

i’ve needed new ones for a while, maybe laser surgery?, i do however stand by my point, that all nations are not adverse to buying assets from each other, why not us?why not? cheap=more.

And where does all the money come from to pay for that fantasy fleet?

which one where? are you a marine engineer? i am

from the place that wastes millions on unproven astute submarines when 1.4 billion would pay for new escorts or the full t26 order


Even the Yanks were impressed by Astute.

the yanks are impressed by anything.

foreign aid cuts £13.4 billion last year., how many type 45’s for that?

Meirion X

John Clark# The RN Did Not procure 16 Type 23’s as configured for Full ASW. The MoD sold 3 Type 23’s in 2005. Only from 2004 were 8 Type 23’s fitted out with 2087 Towed-array-sonar.
I like Andy’s idea of procuring more OPV’s configured for ASW, fitted with Towed-array-sonar.
Far Cheaper then procuring more Type 26’s!

faster to do as well.

One ship to cover how many hundreds of miles of open water? Even with an embarked helicopter and the soon to be reintroduced MPAs, it seems a tall task for a lone frigate. Yet it also seems a waste of a T26 that’s been outfitted for expeditionary warfare. The best all round solution would seem to be a modern Type 14 Blackwood frigate: aside from decoys, a couple of light guns and a CIWS, they’d be small, ASW only platforms for the GIUK gap. Single 8 cell Mk41 for ASROC, ideally a flight deck capable of Merlin, hull and towed… Read more »

Cam Hunter

Why not add a ASW on a river 2, they can work with merlins also. But prob better with the type 31 for that role, and keep the type 26 for global operations after all it is a GCS. All our frigates should have some kind of anti submarine role.

The existing patrol ships already have their own tasks to perform. If we appropriate them to patrol off western Scotland and the GIUK gap, we won’t have any ships protecting our fishing areas or performing maritime security roles.

if the type 31 ever actually happens i have my doubts

type 31? i’m starting to think it is’t going to happen

i think a ‘batch 2 type 21 type ship would be just the job. upgraded design, the latest;bells and whistles, cheaper than a t26 faster build, slightly smaller than a type 26, it could be a template for the type 31 which, i’m beginning to doubt will ever happen.

Any one know how many hulls it takes to have one available 365? Its either 2 (if not deployed often), 3 (following rule of 3s) or 4 (following the nuclear sub numbers)

the blackwood class had its merits cheap, quickly built, very quickly built and a similar vessel with modern ‘gadgets’ is just what the t31 should be, with as much autonomous equipment available to keep the crew,size and costs down.without sacrificing efficiency.

Morning all.

The way I see it.

The greatest threat to our Bombers, if there is one, is another submarine.

Once the V boat is into open sea and deeper waters and has not been picked up by a lurking Russian sub it is pretty much invulnerable, cruising at slow speed.

Look what happened with the French Bomber a few years back.

But while transiting from Faslane on the surface or in shallow waters it could theoretically be picked up and tailed.

Hence the TAPS.

Mr Bell

We need more ASW assets. Agree with post above- return the type 26 order back upto 13 hulls- they must be cheaper now the development cost is already being spread around 32 ship order confirmed already. 15 Canada (way to go Canada- nice big order), 9 Australia (their type 26’s will be the most heavily armed and capable akin to a shrunken Arleigh Burke in missile load but better at ASW), 8 UK- not enough. Once type 26 order returned to 13 and we have order 10 of the Arrowhead design for type 31e then we are getting somewhere- the… Read more »

more astutes? sorry, but at£1.4 billion each, there’s no way that would happen, whit i’d do is try to negotiate the return of the 4 ex’upholder class from canada, in exchange for retiring t 23’s the whole upholder class issue was an utter disgrace 4 built out o a planned 12 two of them served the U.K for just two years! and one of them h.m.s unicorn gave the R.N ONE YEAR. all are still in use as the victoria class 4 more CHEAP SSK’S? why not?

Mr Bell

Slight problem with that idea, the Canadians have just updated all the old upholder class and are happy to retain them in service until the late 2030s. Your point is a good one though. We did sell them off cheap when we should have put them into a reserve fleet. UK does this all the time, sold for scrap or sold off cheaply.
The USN has a massive reserve fleet why can’t we? I would retain all the type 23s. Lay them up somewhere then reactivate them if needed once they have had new sensors and a refit.

Have you remotely any idea how much that would cost? Warships need a huge amount of care and attention, even when alongside to keep them remotely sea worthy. To reactivate them would probably take 18months at least. That’s 18 months per vessel. It’s simply not economical or practical.

maybe even use use them to get back the type 22’s still in service with chile, brazil and romania. the t22 was almost designated as a destroyer. maybe, a t22 with towed array artisan, sea ceptor,asw weapons would be a good move. especially as THEY’RE ALREADY BUILT.

Meirion X

13 Type 26’s is a total fantasy, and Unnecessary for just home waters!
Procure OPV’s or small frigates configured for ASW, and with noise damping, and towed-array-sonar.

if the dockies at portsmouth could build the worlds first battleship drednaut in under 12 months the expectation on the clyde should be that two ships minimum is an acceptable justification for the clyde to keep getting contracts that should have gone to other u.k yards


It would have been, Andy, if there had been a genuinely firm commitment for the 13, and not so many delays. BaE planned a £200 million frigate factory capable of exactly that, 2 a year. But cancelled, and you can’t blame them.

In addition to that, with the delay half the workforce went down to Barrow supposedly, to help out on Astute, as the OPVs didn’t need so many.


In addition they stopped taking apprentices for a while, the lifeblood of an industry. Back again taking on, now the 3 T26s are ordered.


Why not retain a type 23 hull specifically for this job? Yes they are getting on a bit, but this isn’t the most demanding patrol job for the hull I’d imagine.

Sure there’s a really good reason why my cunning plan won’t work, and I’m sure someone will be quick to tell me what that is…

the ships that could do the job, but aren’t fitted out to do it are the batch 2 rivers but the outfitting and design changes to the actual ships might not let it actually happen

reconfiguring the b2 rivers for asw seems to make sense

Mr Bell

Agree or better still 2 of them. They can be listed as the Clyde guardships and who knows if Scotland ever get their independence they can be the Scottish navy.
Just waiting for a Dad’s Army reply on that one. Cannot wait for the nazi. I mean nationalist reply.

an independent scotland would be like ireland, expecting the cover from the rest of the u.k without contributing to it


Daft comment. Ireland is a Partner for Peace, with a defence budget of just 0.3% of GDP according to the EU for 2016, though I think it’s actually a bit higher.

The SNP plan was full membership and EU average, roughly 1.6%, though I think it’d probably be more like 1.8% come the day, to keep up with a 2024 target.

A Conservative, Labour or even LibDem government would be unlikely to be worse than that.


Cost. Cheaper and more effective to have one of the 8 T23 / T26 rotate, plus it’s available for other duties in the area – or exercises further north.


Similar for an Astute (/Trafalgar) by the way, though for different reasons, there’s usually one around.

Mmm, I don’t think that’s a national secret 🙂


@johnf, I wish that SOSUS was still operational but was declassified in 1991 and I think went out of operations in 1993 when the US started to withdraw from Iceland. The US navy started to use the Advanced Deployable System, basically a big towed array on stealth fishing boats in 1996. I think that at the moment Woods Hole is either using the old SOSUS equipment or a derivative for whale monitoring. If anyone can give a fuller update I would be interested. As far as I am aware the US navy is looking into the possibility of restarting a… Read more »


“with a squadron of ASW Merlins shore based to protect our submarine fleet from snooping subs.” that’s what HMS Gannet was there for but, of course, it is now closed as a naval/FAA base.

we’d need ten years for them to be built and purchased


Dam Neck in Virgina has the biggest UK military contingent on the CONUS. The UK/US team run “son of SOSUS” and pass the info to those that need it.


Daft question…. but…

What happens if the frigate picks up a Russian sub attempting to or even successfully trailing one of the vangaurds ?

id hope a ‘ping’ would let the ruskie know that we know he’s there and where he is, but i expect there’s a protocol already laid out for it that the bomber could of course use its own systems to, if required necessary to strike first, but the paperwork needed after wards would need a whole forest to be for the ‘chop’.

Interesting question. Would it mean the Vanguard aborts the patrol?

I don’t believe an SSN would succeed once the Bomber has reached open water.

Nick C

The idea of having a dedicated civilian type vessel just to sanitise the area where the bombers will depart and return is not new. The US had a system called, I think, SURTASS, in the 1980’s, to back up the SOSUS data. Whether they were totally civilian manned or had a coastguard element I can’t remember, but they were fitted with a large towed array system and could cover a very large area of sea. I suspect they went out of service pretty soon after the fall of the Soviet Union. I hadn’t realised that SOSUS was out of service.… Read more »

SOSUS has been replaced by the Integrated Undersea Surveillance System.

Northwood will still get data as before but it comes from the US now not Mawgan.

Agree with the Merlins.

More needed.


I would say we need to invest in small autonomous subs such as the Boeing Orca for exactly this sort of purpose. Cheap, unmanned and low cost to run. Have half a dozen operating simultaneously, all networked to work together and can chase the pesky ruskies away.

Too small. Why do you need a submarine to do the job. As surface vessel would be cheaper and more effective.

Why do commentators on site like this think that unmanned anything is going to be cheaper, necessarily smaller, etc?

An Orca comes in at around £10 million a piece and has a range of 6500 miles. Not fully developed yet, but there are plans to use it asw, mine hunting and patrol, and will have a taylorable mission bay of sorts which can be used to house torpedoes. not yet fully developed but when it is will be a fantastic capability. Many on this site have stated that the best way to hunt a sub is using a sub. So Steve, why have a frigate with 100 plus crew, burning huge amounts of diesel, housing multiple other capabilities not… Read more »

I am not a dinosaur. For my sins I actually know how ships are screwed together…….. Unmanned things still need wetware to maintain and operate them. Sensors have to have be a certain size for them to work at sufficient ranges and for that to happen they need a certain amount of power, which requires either a generator or some form of storage. If a sensors fitted to a £10 million hull works that well then the seas would be invisible to those fitted to an SSN. It seems around here all you have to say is unmanned or F35b… Read more »


Dont forget the bandwidth issue.
Underwater comms are slow and noisy. Thats why VLF comms to subs are usually short code letters calling a sub to Satcom depth.
For effective data transfer you need a satellite and a huge data pipe to transmit the data down.
People at home struggle to stream BBC iplayer on a 10meg fibre. Imagine the limitations on complex oceangraphic data that would need 10Gbits of bandwidth.


So an attacker just needs to sink the TAPS to significantly make our nuclear deterrent vulnerable as it enters or leaves Faslane?

I’d be surprised if they are not staggered.

So there should be no interference with CASD.

I don’t think it is a case of two Bombers passing each other and the crews waving!


That’s an act of war and I somehow doubt the going on patrol SSBN waits till the on-patrol one returns. Needs working up I guess, anyway.

And where does all the money come from to pay for that fantasy fleet?

same place as the money for carriers, astutes and dreadnoughts halving the£13.2 foreign aid budget would go a way to paying for it.


Thanks for the article, I do quite often see a T23 stooging about, or on marinetraffic. And usually when there’s a JW, with Defender visiting Glasgow curses didn’t know about the under-publicised tour so missed it and didn’t find a viewpoint on the North side of the Clyde (or south) though maybe I gave up too early. Oh well, have seen one or two T45s on the Clyde in the past. Not the same as being able to aboard 🙁

If only you knew the state of the type 23 fleet a barely floating heap of patchwork metal rustbuckets not fit for f all i’m sick to death of looking at the damned things.

Hence why the urgency for the T31’s I presume.

Where’s the urgency?

is the t31 actually going to happen? i think not.

Marc – yes they are getting on a bit but you ask any Akula or Kilo commander what he fears the most topside is a ASW spec T23 looking for him

they are still very very quiet when using towed array – quieter than most other ASW platforms, the T31 won’t be a dedicated sub hunter – that’s the 26.

from a propulsive and acoustic angle they are still top drawer

Meirion X

Why tie up a Type 26 hunting subs. in home waters??
A corvette configured for ASW and fitted with TAS, will be good enough to patrol home waters for subs.


The RN has no corvettes as such, so it’d need a new class of ship with all the design and development costs and build based on just 3 (or 4) ships. Plus different crewing requirements and training. Or redesign the River class to be suitable – same expense.

Cheaper just to rotate a T26 from the (small) fleet of them, also able for other duties. Plus the T26 is expected to be superior at detecting silent subs. “Silent” hulls ain’t cheap.

Meiron X

I am sure that a new build River Class opv, could be modified for full ASW much cheaper then procuring a complete Type 26 frigate. If so, procure 3 or 4 for home waters.

The money is not in the hull cost, it’s the acoustic dampening and noise cancelling equipment. Engine and gearbox mountings, shaft lines, genesets, blown cpp propellers, sheilded moving parts.

you cannot get that into any size hull and make it cheap

a River with towed array would sound like a bag of gravel in a washing machine


Thanks for that.

Meiron X

I wonder what is smallest size frigate you could get full ASW kitted?
The Italian Navy is planning to procure 3 of PAA frigates as 4500ton 133m ASW vessels.

Meiron X

The PPA frigates are made by Fincantieri.
I wonder if these frigates be useful to the RN as small ASW frigate? Link below.

Does any know why UKDJ stop publishing new articles?


and they’ll get them faster than the R.N will get the t31


The US once had dedicated towed array sonar boats (actual boats not ships) no weapons (not even self defence) and mixed crews civilian/navy

Could the UK have a use for something like this as a way to keep the CASD safe etc ? After all if it’s fully supported by maritime patrol aircraft it can direct the teeth effectively, while being small silent and cost effective.

could an archer pull a towed array?


Well the stalwarts were 1,650 ton, 68m boats, they towed a 6000 feet passive array, but did not do on boat analysis of the data.