Merlins Chasing the Chasers

[FD2]

At last a well written article about modern ASW work. No doubt the sonobuoys are much more capable than those that were in use when the RAF so capably helped us get the system into service in our Sea Kings during trials back in the mid-seventies in 814 Squadron. After all they had been using the system for years before that.

There wasn't much room for the plotting table behind the observer and U/C and the c of g was a little more to the rear but it worked and now the Merlins will have a fully fit for purpose, integrated fit. Sorry it's a large extract from behind the Telegraph's paywall.

Hunter becomes hunted as Royal Navy helicopters hound Russian submarines

British aircraft drop specialist sonobuoys to search for vessels in the eastern Mediterranean that had been stalking Carrier Strike Group
By Dominic Nicholls, Defence and Security Editor 9 July 2021 • 8:02pm



A Russian submarine stalked the Royal Navy’s Carrier Strike Group (CSG) prompting a helicopter hunt for the vessel, The Telegraph can reveal.

Merlin helicopters were scrambled to search for the Russian submarine when the group was passing through the eastern Mediterranean.

The two aircraft dropped sonobuoys - equipment designed to sink beneath the water to find submarines - to listen for its distinctive sounds after it was suspected to be monitoring HMS Queen Elizabeth, Britain’s new aircraft carrier, and escort ships.

The hunt for the submarine took place four days after the confrontation in the Black Sea between HMS Defender, a Type-45 air defence ship, and Russian forces.

Russian submarines are known to be active in the eastern Mediterranean from the Tartus naval base on the Syrian coast.

Their primary mission is to lurk just off the coast of Cyprus, monitoring RAF aircraft launching from RAF Akrotiri to strike Daesh targets in Syria.

It is not known if the Russian boat - understood to be a diesel-electric Kilo-Class submarine from the Black Sea fleet - was caught unawares as it monitored British air operations, or if it was diverted specifically to spy on HMS Queen Elizabeth.

Two Merlin Mk2 submarine-hunting aircraft were launched, one from HMS Queen Elizabeth, the other from the Royal Fleet Auxiliary ship Fort Victoria, a replenishment tanker.

It is not known if the USS The Sullivans, an American destroyer, or HNLMS Evertsen, a Dutch frigate, both contributing to the CSG, took part in the mission.

The Telegraph understands at least one sonobuoy was dropped from the Merlins.

There are seven such helicopters deployed with the group, and these would likely have been operating in coordination with other anti-submarine assets. These include the two Type-23 frigates HMS Kent and HMS Richmond and the Royal Navy’s deployed hunter-killer submarine, thought to be HMS Astute or HMS Ambush.

While the MoD refused to confirm the incident, understood to have occurred on June 27, it said "robust measures" were in place to protect the CSG, which is on its first operational deployment.

Defence sources have suggested the suspected Kilo-Class would likely have come from Moscow’s Black Sea fleet.

Ryan Ramsey, a former Royal Navy submariner and commander of the world-renowned Perisher training course, said: "Submarines aim not to be detected – it stops you completing your tasks.

"Evasion in a submarine is really difficult when you’re going up against something as capable as Merlin helicopters. The UK has always been really effective at anti-submarine warfare using ships, submarines and aviation.

"When I was teaching the submarine command course, Perisher, it was the Merlins that the student captains worried about the most. I’m sure the opposition are doing the same thing."

The Russian Navy is thought to operate only diesel-electric boats in the Mediterranean, preferring to keep its nuclear powered submarines - capable of long passages submerged - in the North Atlantic, where they mainly shadow Britain’s nuclear deterrent.

Although older boats, diesel-electric submarines are quieter than nuclear powered vessels as they operate only on battery power when submerged.

However, they periodically need to hover near the surface of the ocean and run their diesel engines to replenish the batteries.

They use a "snort mast" to extend above the water to draw in air. This dustbin-sized piece of kit has a radar signature detectable to Merlin helicopters.

The Merlin Mk2 fleet of helicopters entered service in 2014 as an upgrade for the original 1990’s Mk1 naval version. It is the Royal Navy’s principal airborne anti-submarine warfare capability.

There are 30 Mk 2 aircraft in the fleet and each one carries a crew of five. They can be armed with Sting-Ray Torpedoes, Mk11 Depth Charges and the M3m .50 Calibre machine gun.

A Ministry of Defence spokesperson said: "We do not comment on operational matters of this kind, but can confirm that robust measures are in place to protect HMS Queen Elizabeth and the ships of the UK Carrier Strike Group."

Since the incident in June, HMS Queen Elizabeth has led the CSG through the Suez Canal. The group is thought to be about to enter the Indian Ocean, on the next phase of its eight-month deployment to the Indo-Pacific.

[FD2]

What is a sonobuoy?

In March this year, British firm Ultra was awarded a £31million contract to supply sonobuoys for the Royal Navy’s Merlin Maritime Patrol Helicopter out to 2024, writes Dominic Nicholls.

Sonobuoys, pictured, are deployed to detect, classify and pinpoint enemy submarines.

Tests and training for the Royal Navy’s sonobuoys is undertaken at a special facility at the British Underwater Test & Evaluation Centre in North West Scotland.

The sonobuoys used on the recent operation would have been dropped from the aircraft and not connected physically to the helicopter.

Several can be dropped to create a barrier or underwater net to catch submarines.

Operating at different depths to ensure signals are not lost in the different temperature layers of the ocean, the sonobuoys usually sink after the mission is completed and are not recoverable.

They are expensive and rarely used for exercise purposes; another indication the activity on June 27 was a live operation.

Sonobuoys can be set to active or passive modes.

In active mode they emit a signal to ‘bounce’ off the skin of submerged objects such as submarines.

Active mode provides range and direction to hidden submarines, provided the oceanographic conditions - temperature and salinity - are right.

However, active sensors will allow the targeted vessel to know it is being hunted.

Passive sensors just listen for sound or other signals transmitted through the water.

It is much harder for targeted vessels to detect passive equipment.

A combination of both systems would ideally be employed across different ships and aircraft if possible to maximise the chances of finding a hidden submarine.

Hunter becomes hunted as Royal Navy helicopters pursue Russian submarines.png (223.9 KiB) Viewed 569 times

[llondel]

I remember sonobuoys from when I worked at a defence company, and that was a long time ago. I guess they're way more advanced now.

[FD2]

Yes - they had been in use with RAF Coastal Command since 1942. Later fitted in Shackletons and then Nimrods for many years. The Navy didn't fit the Jezebel system into Sea Kings until the mid-1970s. Also in use by the USN for many years.

https://en.wikipedia.org/wiki/Sonobuoy

[TheGreenGoblin]

What is a sonobuoy?

In March this year, British firm Ultra was awarded a £31million contract to supply sonobuoys for the Royal Navy’s Merlin Maritime Patrol Helicopter out to 2024, writes Dominic Nicholls.

Almost certainly longer than 2024 as the British Government quietly let it slip out this week that the Merlin will not be replaced from 2024 onwards, but will be upgraded and used until 2040!

https://www.flightglobal.com/helicopter ... 23.article

UK defence officials have quietly extended the out-of-service date for the Royal Navy’s (RN’s) Leonardo Helicopters AW101 Merlin rotorcraft under plans that will now see the heavy, three-engined type operating until 2040.

Until recently, the RN’s 30 Merlin HM2 anti-submarine warfare helicopters were due to retire in 2029, while 25 Merlin HC4/4As, flown by the service’s Commando Helicopter Force, would follow a year later.

[FD2]

Almost certainly longer than 2024 as the British Government quietly let it slip out this week that the Merlin will not be replaced from 2024 onwards, but will be upgraded and used until 2040!

I'm not surprised, because of the time and money it cost to get the aircraft in service - late as well!

[Pontius Navigator]

The Jez bouys didn't come in until the Nimrod. They were A size as shown by the airman loading them. They could only hear noise hence their real name of LOFAR, low frequency analysis and recording. They were not too expensive.

In Nimrod Mk1 we also used much larger 1C bouys. They were the cost of a Mini car and tactics demanded a first pass drop of 4. We were only allowed to drop one in peacetime and then if we were certain there was a submarine.

We could carry 63 A size routinely or 96 occasionally. From 1980s they were replaced with C size. Same capability one third the size.

The ones referred to in the article were probably similar to BARRA or CAMBS buoys. One developed by Oz the other by use.

Beam array which could give direction as well as just recording noise.

Command activated beacon system. I think it could also listen but could then be command activated to go active and ping the target. This meant the submarine could not know where the bouys were until too late.

Other earlier buoys that we cadged from the USN and RCAF were pingers with a high data rate but range only, ie rangers.

One I heard of was DEER Explosive Echo Ranging and I think was DIFAR. Google throws up some interesting hits

[FD2]

Thanks PN. We pilots had a short course at St Mawgan, most of which didn't stick in my brain because I was off outside a few months later. Later we did have a major winter exercise off the north of Norway with elements of the 6th Fleet, including JFK. Dunking sonar at least gave the front seat something to do but those of us in the Jez aircraft were about 100 miles south of Hermes and just stooging around listening to the buoys from a 1,000ft or so. Also trying to avoid the CuNims which sometimes didn't show up on radar - then we only knew we were in one was when the sky turned from very dark grey to pitch black and it got very bumpy.

I seem to recollect from St Mawgan that the ranging buoys meant that a rough fix could be obtained, like a ship's radar ranges from several points of land, but localising it more accurately for an attack was done with conventional pinging from dunking sonar. I can't remember what buoys we had in the back now but I seem to remember it all as LOFAR analysis.

[Undried Plum]

One of the Survey ships on the Trans Mediterranean Pipeline job had a wonderful collection of sonobuoys from a dozen different nationalities. They'd all been recovered from the seabed by the Pisces manned sub. The technicians made a huge wall display of them all, mostly with guts removed and labelled with comments. There must have been over a hundred of 'em.

It was fascinating to see which countries copied the sonobuoys of which other countries. Some of the older Soviet ones had circuit boards which looked like they'd been soldered with a coal-fire poker. Some of the Murricane ones looked like they were rip-offs of the Brit ones. Some of the ffrench ones appeared to be micro-processor versions of the basic design of the Russky ones, and so on. There was even one which had Chinky script on the pcb. Gawd knows who deployed that one.

I often wonder what happened to that display. I guess it got broken up and was taken home piecemeal by the guys who created it. We all got loads of Size A batteries to take home every trip. They fitted, more or less, into the old-fashion long tube torches of those days and they were free and plentiful.

The Cold War was fun. Profitable too.

[CharlieOneSix]

How different today's helicopter anti-submarine warfare is to my time in the 60's. It took 3 Wessex Mk1 to hold a nuclear sub - and only if you were lucky. Leapfrogging each other from dip to dip, no radar, just the 195 sonar and the results of the Observer's chinagraph plotting. If we ended up where he wanted to go he was fortunate as everything was predicated on accurate flying from the pilots.

I think it was in 1988 that I was sent to Westlands to evaluate the EH101, the civvy Merlin, for offshore oil/gas exploration flights in the North Sea. The one I saw was a very early prototype. There were so many disadvantages to it at that time, cost of an airframe, two single main wheels which would have exceeded load limitations on most offshore platforms, plus a side cargo access (no ramp then if I remember correctly) which was far too high for quick turnarounds of baggage offshore. Impressive though!

In 1995 one of the pre-production Merlins from Yeovil had a problem at 12,000ft over Devon.The crew of 4 had to take to their parachutes. https://www.independent.co.uk/news/uk/c ... 14706.html

Incidentally it was never meant to be named the EH101. EHI stood for European Helicopters Industries, a joint venture with the Italian company Agusta. It was their first project and the name was intended to be EHI 01.

[Pontius Navigator]

One gorgeous exercise in the Med, we had contact on an Orange RNlN sub. We had used our allocation of stores but had acquired a quantity of RCAF pingers, I forget what we swapped with them.
We had her held down with buoys pinging her from all sides. Then two dippers joined in for infotacs and much fun was has by all as the Tijerhai tried to wriggle out.
Better fun was if it was a Soviet sub. Best fun was when they knew you knew.

Very early one morning we had a total failure of our nav kit and inadvertently penetrated the Spanish territorial limits. After feeling our way around for a bit, I remember seeing a man walking his dog on the beach at Malaga, we bounced a Soviet Foxtrot at anchor, some of his deck planking and sides were off for maintenance and we got some good snaps much to their consternation.

[Undried Plum]

Very early one morning we had a total failure of our nav kit and inadvertently penetrated the Spanish territorial limits. After feeling our way around for a bit, I remember seeing a man walking his dog on the beach at Malaga, we bounced a Soviet Foxtrot at anchor, some of his deck planking and sides were off for maintenance and we got some good snaps much to their consternation.

As you do.

[FD2]

At a party in the Mess at RAF Luqa one night (great party guys! ) one of the Shackleton pilots told me about a flight one night down towards the east end of the Med when they, in the cruise, detected a radar echo which looked about right for a snorkelling sub re-charging batteries after sneaking out of the Black Sea. Going into their equivalent of a 'whisper mode' in a slow descent they passed overhead the contact at low level, illuminating the target and taking lots of photos.

After returning to Luqa they saw the results in the Phot Section next day - a very startled couple who had been on the job on the deck of their yacht at the time.

'How was it for you darling?' 'The best one yet with flashing lights and a loud roaring noise!'

[Undried Plum]

Leapfrogging each other from dip to dip

Very Navy.

[Pontius Navigator]

FD2, we did that too with similar consequences though I am not sure I believe the pilot's version.

Anyway, again night, this time south of Alboran, we gained a contact in similar circumstances. We went to action stations and at a mile and a half everything happened at once.

The copilot struck the searchlight, the 1st pilot called lights, the ESM operate called MAD Mark and fired a retro marker and I dropped two sonobuoys. The 1st pilot then confirmed a yacht with the aforementioned activity in the cock pit but at the same time turned back to the flame float.

A brief discussion ensured and it was declared a solid MAD, then the sonobuoys started to draw a contact so we quickly went from Possub to Probsub, as we ran over the datum we got another MAD. We went round again over the two MAD floats and as we were in an exercise area I attacked and dropped an explosive charge.

At this point the Jez team identified the target as a Soviet Juliette class SSM seeking through the exercise area, running deep on batteries and it was just luck that we bounced him.

You can just imagine the consternation at 2am when suddenly BANG!

[Pontius Navigator]

Leapfrogging each other from dip to dip

Very Navy.

Damned uncalled for UP. You should know full well that was the Army in WW 1.

[FD2]

The memory is very vague from that evening PN but we suspected the tale grew with every re-telling. Think the chap’s name was Johnnie Johnson but I was very ‘relaxed’ at the time.

[Pontius Navigator]

FD2, which mess were you in?

I had a very......... session with a deep and meaningful discussion in the Transit Mess bar. Anyway the next night I met someone else and we did the usual ' I think we met before were you at.....' As we went around the air force, base after base, we failed to determine where we had met before. Then the penny dropped. Same bar the night before.

The drink of choice was brandy sours, glass always rimmed with sugar.

[Pontius Navigator]

UP, as you didn't rise to the bait

One staff officer jumped right over another staff officer's
back.
And another staff officer jumped right over that other staff
officer's back,
A third staff officer jumped right over two other staff
officers' backs,
And a fourth staff officer jumped right over all the other
staff officers' backs.

They were only playing leapfrog,
They were only playing leapfrog,
They were only playing leapfrog,
When one staff officer jumped right over another staff
officer's back.

[Undried Plum]

Leapfrogging each other from dip to dip

Very Navy.

Damned uncalled for UP. You should know full well that was the Army in WW 1.

Deck games, y'know.

White or fawn socks, fer hossiffers to be worn of, as middle-lower targets when juggling at moving targets. Hoccifers, for the use of. Discreetly, mostly. That sort of thing, usually.

It's a Dartmouth thing. Just like it's spelled.

We didn't do dat ting at Cranditz, in my day. We had girlfriends outside, for that sort of thing. Y'know, that sort of thing.