UK Defence Forum

Anybody finds this strange?

"The destroyer used her sonar and Wildcat helicopter – armed with Sting Ray torpedoes – to hunt the Trafalgar-class boat, which in turn sought to get Diamond in her periscope cross-hairs without being noticed, a challenge made harder by the near-glass like state of the Mediterranean."

HMS Diamond vs certain HMS Trafalgar-class submarine

https://navaltoday.com/2018/11/07/royal ... urity-ops/

The MFS7000 is allegedly designed for use with the SSTD system, but is usually described as "multi-function", so it may well have some ASW capabilities. Has there been a recent upgrade that they might have been testing? It does seem as if there is a renewed interest in ASW capabilities

abc123 wrote:Anybody finds this strange?

"The destroyer used her sonar and Wildcat helicopter – armed with Sting Ray torpedoes – to hunt the Trafalgar-class boat, which in turn sought to get Diamond in her periscope cross-hairs without being noticed, a challenge made harder by the near-glass like state of the Mediterranean."

HMS Diamond vs certain HMS Trafalgar-class submarine

https://navaltoday.com/2018/11/07/royal ... urity-ops/

Why?

abc123 wrote:"The destroyer used her sonar and Wildcat helicopter – armed with Sting Ray torpedoes – to hunt the Trafalgar-class boat...”

Optimistic perhaps, but not particularly strange.

Simon82 wrote:

abc123 wrote:"The destroyer used her sonar and Wildcat helicopter – armed with Sting Ray torpedoes – to hunt the Trafalgar-class boat...”

Optimistic perhaps, but not particularly strange.

That's what I meant to say, optimistic at least. Also, I was thinking that the RN uses just Merlins in ASW role?

abc123 wrote:was thinking that the RN uses just Merlins in ASW role?

I presume it was a timed experiment: Will the torp (dummies) splash into water, within range, before the target is obtained in x-hairs?
- and not about ASW tactics but testing self-defence ( HMS Diamond not being a sub-hunter) capabilities. A sitting duck, a hope in hell... or slightly better? A requirement for singleton missions, without having an other vessel "in tow":
"proves our ability to deploy, operate and sustain ourselves for however long is required,” said Commander Ben Keith, HMS Diamond’s commanding officer."

Every 'singleton' can't take a Merlin with it, against a sub threat of low likelihood, as the Merlin numbers are "v tight" already, with the taskings they have (and overstretched if you ever put [4+5]+ [4+5] on the two carriers).

ArmChairCivvy wrote:

abc123 wrote:was thinking that the RN uses just Merlins in ASW role?

I presume it was a timed experiment: Will the torp (dummies) splash into water, within range, before the target is obtained in x-hairs?
- and not about ASW tactics but testing self-defence ( HMS Diamond not being a sub-hunter) capabilities. A sitting duck, a hope in hell... or slightly better? A requirement for singleton missions, without having an other vessel "in tow":
"proves our ability to deploy, operate and sustain ourselves for however long is required,” said Commander Ben Keith, HMS Diamond’s commanding officer."

Every 'singleton' can't take a Merlin with it, against a sub threat of low likelihood, as the Merlin numbers are "v tight" already, with the taskings they have (and overstretched if you ever put [4+5]+ [4+5] on the two carriers).

Fully agreed, but, are Wildcat crews even trained in ASW role?

abc123 wrote: are Wildcat crews even trained in ASW role?

Why would you need to be (in this experiment)? All sensors and C&C are operated out of HMS Diamond, on detection the helo is "vectored"
out, saying out as keeping it close is agnostic as to which direction they will need to go
- not even go all the way, but sufficiently within range to make the sub's escape from the torp unlikely, push the release button and "on the splash" the referees will invite you back... for tea & medals

On the Wildcat thread we could discuss if some should receive dipping sonar sets for littoral ASW. Not because they are ideal, but just bcz Wildcats are relatively plentiful (available) and Merlins scarce. Hard prioritisation, outside peace time, will be necessary.
- if the SF Chinook order proceeds, it makes any order for a CSAR Merlin version very unlikely. On the margin, but not by much, they would improve the availability of the rest of the fleet

the wildcat it the weapon delivery platform not a ASW platform however the wildcats for the Philippines are ASW capable so some of the tec may of made its way across

Tempest414 wrote:the wildcats for the Philippines are ASW

And the Marines of ROK use them as flying artillery (with Spike NLOS, aka Exactor). Not so relevant for T45s (CTF), but could be quite an uplift in T31 capability, to have one such when a need is anticipated.. then a pop gun would do (as part of the permanent fit-out)

ArmChairCivvy wrote: On the Wildcat thread we could discuss if some should receive dipping sonar sets for littoral ASW.

That's what I wanted to ask. I didn't know that they are just releasing torpedos cued by ship's sensors...

"cued by ship's sensors", in an indirect fashion of course, owing to the missing data link. The Wildcat drops a torpedo somewhere in the rough area, and whilst it probably has very little chance of hitting, it's probably good enough to scare the sub off for a day.

shark bait wrote: a torpedo somewhere in the rough area, and whilst it probably has very little chance of hitting

Why would you say the chances are low? Even with torps launched from a sub, after "Wire-guided stage" to get it near enough to target, they then proceed to use an autonomous, active terminal-homing sonar.

ArmChairCivvy wrote:

shark bait wrote: a torpedo somewhere in the rough area, and whilst it probably has very little chance of hitting

Why would you say the chances are low? Even with torps launched from a sub, after "Wire-guided stage" to get it near enough to target, they then proceed to use an autonomous, active terminal-homing sonar.

Ocean's a big place, and the possible launch direction and envelopes are even larger, let alone the depth factor. It's like throwing a firework into a department store. Someone, somewhere in there, will hear it and likely flee, but you're not likely to hit them unless you know where they are other than "in the store".

A datalink is not the only way to communicate.

shark bait wrote:"cued by ship's sensors", in an indirect fashion of course, owing to the missing data link. The Wildcat drops a torpedo somewhere in the rough area, and whilst it probably has very little chance of hitting, it's probably good enough to scare the sub off for a day.

Why do you need a datalink to drop a torpedo on a target? The ships sonar has the submarine contact range and bearing, the ship sends out the helicopter and tells it where to drop the torpedo. What's 'very little chance of hitting' about that, even more so if it's a Stingray being dropped..

just as a side Wildcat does have the Bowman system as does every ship in the fleet for secure voice and data coms so sending secure coms and data to and from ship and wildcat is there. So no it does not have Link 11, 16 or 22 but it does have a secure voice and data system

hovematlot wrote:The ships sonar has the submarine contact range and bearing

Does it? In this instance I suspect the only data the ASW officer has with reasonable accuracy is bearing.

Usually the RN uses a hull sonar, towed array, VDS, dipping soar, and sonobuoys to determine the other two dimensions. I like @RetroSicotte's analogy above, it's a bloody difficult task and the RN doesn't invest in those extra sensors for no reason. If the T23 + Merlin dream team struggle, a T45 + Wildcat stand little chance, but still enough to force the sub commander to disengage.

In a perfect world the RN would have a MFTA on the T45 and dipping sonar on the Wildcat.

shark bait wrote:Does it? In this instance I suspect the only data the ASW officer has with reasonable accuracy is bearing

I would have said that that was completely dependent on whether the T45 was using sonar in passive or active mode (the MFS7000 can do both and also use a lightweight towed array as part of the SSTD system).

shark bait wrote:

hovematlot wrote:The ships sonar has the submarine contact range and bearing

Does it? In this instance I suspect the only data the ASW officer has with reasonable accuracy is bearing.

Yes it does. The principle of active sonar - you transmit a sound wave, it bounds off the target back to the receiver. There's your range and bearing

abc123 wrote:Anybody finds this strange?

"The destroyer used her sonar and Wildcat helicopter – armed with Sting Ray torpedoes – to hunt the Trafalgar-class boat, which in turn sought to get Diamond in her periscope cross-hairs without being noticed, a challenge made harder by the near-glass like state of the Mediterranean."

HMS Diamond vs certain HMS Trafalgar-class submarine

https://navaltoday.com/2018/11/07/royal ... urity-ops/

In this discussion, the submarine periscope appears to have been forgotten. The Sub Captain will have been using the periscope to measure the bearing and range to the target, along with the target's own heading and speed. This will take multiple periscope observations.

Wildcat has a very good radar, very able to spot a periscope. T45 has a very good radar, very able to spot a periscope. The "near-glass like state of the Mediterranean" would mean that the many Mk1 Eyeballs available on the Wildcat and T45 would also be very good at spotting a periscope and its wake.

The poor sub Captain will know all this, so will only leave his periscope above the surface for a few seconds at a time. But then he is blind. So he will need to check with the periscope to see if he has been spotted and the T45 is heading towards him at flank speed. All the time, the T45 captain will also be zig zagging around making his future position very hard to predict.

Submarines are still more frequently detected by spotting their periscope than they are by sonar.

hovematlot wrote:Yes it does. The principle of active sonar - you transmit a sound wave, it bounds off the target back to the receiver. There's your range and bearing

True, I had my head stuck in passive mode, but I suppose a noisy destroyer doesn't have much to loose by going active.

hovematlot wrote:

shark bait wrote:"cued by ship's sensors", in an indirect fashion of course, owing to the missing data link. The Wildcat drops a torpedo somewhere in the rough area, and whilst it probably has very little chance of hitting, it's probably good enough to scare the sub off for a day.

Why do you need a datalink to drop a torpedo on a target? The ships sonar has the submarine contact range and bearing, the ship sends out the helicopter and tells it where to drop the torpedo. What's 'very little chance of hitting' about that, even more so if it's a Stingray being dropped..

Exactly and that has always been the way most RN ships have done ASW, historically very few ships have had the benefit of TAS. A hull mounted sonar is always more effective when used in active mode giving both range and bearing and then passing that data to the Wasp or the Lynx.

Also IMHO the very reason why without a Merlin capable hanger (or even with) the T31 must at the very least have a hull mounted sonar ( I refuse to use HMS!) Leander or not, in fact the Leander brochure makes this very clear.

Of course fitting a dipping sonar to the Wildcat would be great but probably comes at too much cost and range and payload would suffer too. Does anybody know if any consideration has been given to using sonar bouys instead ? Lightweight, cheap, and we will soon have them in service again on the P8 ,I'm sure Ultra would be more than happy to come up with a Heli born rig ?

(Ships, planes and gaming) 23 Nov 2018

HMS Diamond (D34) returned to Portsmouth today after a two month deployment to the eastern Mediterranean Sea.