The Type 26 Frigate is an advanced submarine-hunting vessel, and by virtue of that fact, the class needs to have a low acoustic signature.

The black sections of the hull, shown in the image above, are part of an effort to reduce the noise generated by the vessel, making her harder to detect by enemy submarines.

Acoustic shielding is an important aspect of submarine design, but they’re a rare appearance on the external hull of a warship.

This innovation on Type 26 helps to protect the vessel and its crew from the dangers of errant underwater noise. Submarine hunters are often forced to operate in close proximity to other vessels, both friendly and hostile, and the sound of their engines, sonar, and other machinery can be detected by sensitive underwater microphones. This can put the frigate at risk of being detected and targeted by enemy forces.

To mitigate this risk, submarines and now Type 26 Frigates are equipped with an acoustic shielding system, typically known as anechoic tiling. This shielding takes the form of a thick layer of sound-absorbing material, such as rubber or other special composites, that is applied to the hull. The material is designed to absorb and dissipate the sound waves generated by the submarine’s machinery, making it much harder for enemy sensors to detect the vessel.

A well-known example of their usual application is shown below.

Anechoic tiles on the hull of HMS Triumph. Two patches of missing tiles are visible towards the forward edge of the sail.

Anechoic tiles are special tiles that are designed to absorb sound waves and prevent them from bouncing off surfaces and creating echoes. These tiles are typically made of a porous, sponge-like material, such as rubber or foam, that is coated with a layer of metal or other reflective material. When sound waves hit the surface of an anechoic tile, they are absorbed by the porous material, preventing them from reflecting back into the environment.

In addition to protecting the vessel from external threats, acoustic shielding also helps to reduce the amount of noise inside the vessel, improving the crew’s ability to hear and communicate with one another. This is especially important in combat situations, where clear communication is critical for success.

Acoustic shielding is just one of many technologies used to make this ship stealthy and effective as a cutting-edge submarine hunter, the others are a bit more complex, and I assume quite a bit more secret.

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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. George is on Twitter at @geoallison
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David Lloyd
David Lloyd
1 year ago

Having watched the excellent Tom Hanks film “Greyhound” the other night, I still think our subhunting frigates should be fitted with Stingray torpedo tubes. Admittedly, they are a shortrange weapon, but who knows how close an enemy submarine could get? Plus, several countries are looking at anti-helicopter and anti-MPA systems on their boats.

Angus
Angus
1 year ago
Reply to  David Lloyd

100% in agreement with you and the cost would be next to nothing in the scheme of things. The sub hunters do require more than one way to kill a sub as that helo may not always be available. Come on MOD you have the space already allocated for them so now jut put them in their space.

maurice10
maurice10
1 year ago
Reply to  Angus

I should imagine there is a ‘Don’t rock the boat’ (excuse the pun) policy at the MOD at this time. This would undoubtedly include additional equipment on, in-build projects, so I doubt the blazingly obvious ideas will see the light of day.

andy reeves
andy reeves
1 year ago
Reply to  maurice10

there has always been a we know best so don’t tell us what to do. the admiralty habitually gets away from its share of the blame for the inability to think outside the box and do more with what we have thn be innovative, with new ideas and methods patrol boats that could be warships and frigates that could be destroyers or even cruisers.a lot of money goes to these crusty relics, from times gone by, money that could be ysed to better effect elsewhere in the service, such as added assist to people who are stuck in the 1870’s… Read more »

IKnowNothing
IKnowNothing
1 year ago
Reply to  Angus

I would imagine they may be hoping to use the heavy lift UAV that is being looked at as a torpedo delivery system in future. Or its replacement. Or the one they commission when they have finished evaluating this one.

Spyinthesky
Spyinthesky
1 year ago
Reply to  Angus

I see that the US is putting winged attachments to their lightweight torpedos adding considerable range to them sounds like a very logical step if you have the capability to discover the submarines.

Coll
Coll
1 year ago
Reply to  David Lloyd

Most likely to be delivered by helicopter. Not great if it’s tied up doing something else.

Last edited 1 year ago by Coll
James
James
1 year ago
Reply to  David Lloyd

Agreed its a good movie, wasnt expecting much from it to be honest but really enjoyed it, only annoyance is I cannot get that sound out of my head every time the U boats made an appearance!!

andy reeves
andy reeves
1 year ago
Reply to  David Lloyd

u think that, seeing the archers labelled with H.m.s,think if they are designed for a 20mm, then they should be fitted many nations count their missile boats as front line unit and equip them accordingly for me, a we’ll drilled squadron of archers, forward based could be a useful tool in the gulf or at Gibraltar the Iranians have fitted torpedo tubes to fishing boats! we have more than we remember we have

andy reeves
andy reeves
1 year ago
Reply to  andy reeves

operating in unison with a t31 perhaps l.

Tommo
Tommo
1 year ago

Or is it, as we called “Boot Topping ” and they haven’t got round too finishing painting the Hull ?

Supportive Bloke
Supportive Bloke
1 year ago

‘These tiles are typically made of a porous, sponge-like material, such as rubber or foam, that is coated with a layer of metal or other reflective material.’

Ummm maybe not?

If there is a metal coating, would it maybe undo the effect of the spongy material bit?

The amount of energy is not large it just needs to be not reflected or dispersed.

You might impregnate the matrix with metal powder to disperse the sound and to increase the effective mass and therefore Q of the composite matrix?

David Barry
David Barry
1 year ago

Send code settings, over.

Supportive Bloke
Supportive Bloke
1 year ago
Reply to  David Barry

🙂

David Barry
David Barry
1 year ago

Would one not also internally tile the hull?

I thought the idea was to reflect waves from energy?

Supportive Bloke
Supportive Bloke
1 year ago
Reply to  David Barry

Internally tiling won’t do that much – you need to stop the acoustic energy getting into the metal structure. The tiles then prevent it radiating.

That said there will be acoustic treatment to the internals to prevent metal sections from ringing or soaking up ambient sounds. That will be more like car panel treatments.

Deep32
Deep32
1 year ago
Reply to  David Barry

In short yes. The RC and ER have internal tiling in various areas.

Rfn_Weston
Rfn_Weston
1 year ago

The thin metal coating does not stop the sound vibrations from penetrating the hull.

I think the idea is to stop back wall reflection from within the hull structure and the porous material achieves this by dissipating the sound waves. Meaning the metal coating on the outside does not interfere with the porous materials function as it works once the vibrations have already passed through the thin steel outer and are on their ‘way back out’.

Supportive Bloke
Supportive Bloke
1 year ago
Reply to  Rfn_Weston

Then that would be sandwiched between layers of the lossy material and not on the outer surface.

Rfn_Weston
Rfn_Weston
1 year ago

I’m not sure why but I fear we are misunderstanding each other! 🙂

Supportive Bloke
Supportive Bloke
1 year ago
Reply to  Rfn_Weston

It is perfectly possible we are at crossed purposes…!!

Ron
Ron
1 year ago

What is the ad London live first masterstroke by Sunak. It leads to scam re crypto currency pretending to be BBC?

ABCRodney
ABCRodney
1 year ago

If anyone looks at the photos taken when the 2 hull sections were rolled out these have been in plain site for the last 18 months. https://www.navylookout.com/wp-content/uploads/2021/05/HMS-Glasgow-SBOH.jpg As far as I am aware the RN was the 1st Western Navy (WW2 Germany doesn’t count) to use anechoic tiles on its submarines in the 80’s on HMS Churchill. Given that nearly every navy now uses them and the RN has historically built quiet ASW Frigates I think it is a logical extension of the idea. I’ve never seen them on any other Navy’s ships (yet), anyone know any different ? It… Read more »

Spyinthesky
Spyinthesky
1 year ago
Reply to  ABCRodney

Why I would hope they have 2 helicopters aboard when in action. That said hardly likely we have enough helicopters around to do that with many of these frigates. Seriously do need the heavy drones at the very least. With all the clever stuff achieved these days even in detecting subs, it really does seem strange to me that advances in killing submarines has relatively stagnated.

ABCRodney
ABCRodney
1 year ago
Reply to  Spyinthesky

Bar depth charges, conventional or nuclear every ASW system relies on an ASW Torpedo regardless of delivery method. The issue with Helicopters or drones is that they cannot always fly due to the weather or visibility, and as our prime ASW area is the North Atlantic or Artic surely we need something else. ASROC would do it, but only if you fit MK41 and adds another new weapon system to be bought, stocked and maintained (probably 2 new weapons as it uses US Torpedos). So other than depth charges why not just stick the twin tubes we already have bought… Read more »

Gunbuster
Gunbuster
1 year ago
Reply to  ABCRodney

You need to consider how to load/reload tubes. Ammo routes from the Air Weapon mag to the tubes needs to be flat as you move the Torpedoes on Torpedo Trolleys. How to lift it from the trolley and into the tube. Didsbury Hoists or fixed hoists? Lifting frames . HP air supplies for the discharge flasks.
I saw the concept art for tubes in a container . Great …my first thought though was how do you load the tubes and where are the reloads. housed.

Gunbuster
Gunbuster
1 year ago
Reply to  ABCRodney

Why fly?
Drone boats with a simple angled storage tube that let’s the torp slid into the water could be used.
It’s going to be difficult for the sub to detect a small water jet powered boat that’s loitering at range on a detected subs bearing.

You wouldn’t beleive the sea states helos can launch fly and recover in. Stabilisers are a massive help .You can always make a flying course to ensure the deck and wind is within the SHOL. The pictures you see of helos on deck at crazy angles are not flying courses.

ABCRodney
ABCRodney
1 year ago
Reply to  Gunbuster

Why make it complicated ? The idea of the tube launch is it last ditch and simple, it isn’t the favoured option that will always be the Helicopter.
But as we all know some subs really are stealthy and have been known to really close undetected. Just ask the USN !
Which is when you want something to launch ASAP, like right now.
Why is it I can’t find any other major western Navy that doesn’t fit them ?
US, France, Italy, Germany, Canada, Sweden, Denmark, Spain, Canada, Australia, S Korea, Japan etc etc etc.
But not the RN ?

AlexS
AlexS
1 year ago
Reply to  Spyinthesky

You cannot operate effectively 2 helicopters in T26 even if you had them.
One of its big design mistakes.

Gunbuster
Gunbuster
1 year ago
Reply to  AlexS

It has a Chinook capable flight deck which is considerably larger than the T22 deck that operated 2 Lynx/Wildcat. You fly one and leave the other in the hangar /mission space or park it fwd folded or spread with the nose and fwd blade into the hangar. You could carry a Merlin and a Wildcat. Merlin to hunt and Wildcat to pony.
On top of that there will be drones in the coming years be they surface or air assets.

AlexS
AlexS
1 year ago
Reply to  Gunbuster

You don’t move a 10ton helicopter in and out of hangar by hand.

Gunbuster
Gunbuster
1 year ago
Reply to  AlexS

No you use a battery powered traction unit that attaches to the front wheels. You control it via a joystick box . It’s a great bit of kit and far better than the old unit and also a lot quicker to use than the wires and rails. Obviously it’s use is dependent on sea state but you can use running lashings if needed. Lynx /Wildcat is push able . Done it many times in the past. You have lots of options for moving helos and all are well established. From experience always remember to take the wheel brakes off first… Read more »

AlexS
AlexS
1 year ago
Reply to  Gunbuster

This only applies to EH101 since RN Wildcat is not ASW. It is a big mess having to take one helicopter out of hangar to push other inside to the “cargo” zone. They have to be side to side on the deck which is not advisable.

william james crawford
william james crawford
1 year ago
Reply to  ABCRodney

why does the prototype German U-boat covered in anechoic tiles and lying at the bottom of the Channel not count? My understanding is that the tiles performed perfectly but the sub ran into a sub-surface mine.

ABDRodney
ABDRodney
1 year ago

Because the post and comments relate to modern developments so Cold War and post Cold War.
Besides which there is virtually no cross over between what they had to use and modern materials.
It is fair to say that a lot of modern ideas are developments of older ones. WW1 drones and I have a struggle to look at the “modern” German Type 201, 205 and 206 without seeing the RN ‘R’ class as a time warp.
Yep we designed a Hunter Killer ASW sub in WW1 which looked spookily like the later German ones.

River Rha
River Rha
1 year ago
Reply to  ABCRodney

If I’m not mistaken, It would seem that due to My Experiences of NHS Queen Elizabeth University Hospital in 2022 I would seem to have had something of a Grandstand View of the Forward Hull of HMS Glasgow sitting on the Quayside of BAE Govan Shipbuilders in the process of preparing for the Launch, Albeit It Would Seem I Was Concerned that Launching at Glen Mallan might be fraught with Hazards ~ Thankfully Not.

Dave
Dave
1 year ago

Fin, on the caption for Triumph! Not sail!

😀

Jim
Jim
1 year ago

Surely this can’t be the case as the Burkes don’t have them and as we are all aware America is the best at everything. 😀

Clayton
Clayton
1 year ago
Reply to  Jim

Now now be fair. They do have super awesome rail guns, no wait, hypersonic missiles, no wait million $ a shell mega killer turrets, no wait – oh sod it. We’ll be here all day 😂

Peter from San Diego
Peter from San Diego
1 year ago
Reply to  Jim

The BURKE DDGs have an active system known as Prairie/Masker (as well as significant design features isolating noise-making machinery from the hull itself.
I question the practicality of using anechoic tiling on a surface ship, as the hull is subjected to a lot more abuse than that of a sub’s, but I’ll take the author’s word for it.

Gunbuster
Gunbuster
1 year ago

Prairie /Masker was fitted to T22 and T42 It took bleed air from the engines and blew it out of holes in the Hull to coat the Hull in a curtain of bubbles . It also blew air out of the the CPP blades to help reduce cavitation. ABs machinery spaces have the usual noise isolating features you see on most ships although nothing as specialist as fitted on T23 ( and I would guess on T26) Vibration mounts, rubber bellows on pipes. It’s pretty similar to that seen on T22 and T23 RN ships of 25 years ago.Praire Masker… Read more »

Peter from San Diego
Peter from San Diego
1 year ago
Reply to  Gunbuster

Thanks for the history lesson. Surface ASW is an interesting design problem (most only concern themselves with weapons and sensors) when it comes to radiated noise. I put DD965 (SPRUANCE class) in commission and served onboard for five years. During that time we, as only the third of the class in the water and the second on the West coast, were participants in just about every FLEETEX, COMPTUEX, RIMPAC, etc. that came along. I remember vividly reading a classified after-action report from one of our attack subs that reported during the exercise we were tracked a couple of times, but… Read more »

Miv Tucker
Miv Tucker
1 year ago

Underneath the tiles it looks like the structure is rusting?
Can that be correct?

AlexS
AlexS
1 year ago
Reply to  Miv Tucker

Yes, it is normal after a lot of time at sea.

Dave
Dave
1 year ago

They all have tricks up their sleave but in a war situation they might not work as well as expected.only things I can think to brag about would be spitfires harriers mosquitos and sonar.
Ships rely more on the capability of its complicated weapons systems which change so fast.
As Ukraine has showed us ships can be a liability as easily destroyed by drones.
And who would have thought that tanks are becoming a thing of the past.

Gavin
Gavin
1 year ago

Why after this article tells us what the black parts on a ships hull are for, Surley the whole of the hull and not just sections would be covered to eliminate or at least reduce a greater chance of being detected by the noise the ship makes. The only thing that comes to mind is if the weight would be to much for the ship since the materials are porus & would make the ship sink which would make me think this was an after thought which was added to the ship

andy reeves
andy reeves
1 year ago

interesting stuff