Future ASW

[donald_of_tokyo]

Is this really the case? As you may know, my ignorance abounds on such matters, which is why I’m here asking such questions. Can a T45 with only a HMS have a realistic chance of detecting a submarine before it falls within torpedo range? If it can, can it actively track it and maintain a position beyond torpedo range until the Merlin is capable of taking off and investigating/prosecuting? I’m thinking about times when the Merlin may not be available due to maintenance or poor weather conditions.

Sorry not "I know", but "as I understand":
- T45 HMS is not good enough to "beat" Subs. It can do something, (say provide a sonar screened area that subs cannot stay without being detected), but if it is 1-by-1 hunting, sub will detect T45 much before T45 detect Subs. So Subs hunts T45, not vice-versa.
- I know, T45 carries ship-turpedo-defence-system, a set of anti-torpedo soft-kill scheme. I understand it has a so-so good (but far from perfect) possibility to get rid of a torpedo. For Sub, it will be important to reach near the T45, so that soft-kill cannot be effective.
- When someone is saying T45 with Merlin for ASW, I "guess" it is just using the Merlin as "one of the 9 Merlins" needed to do, hunter-killer operation in 24/7 basis. In this case, Merlin do search for subs, and not rely on CAPTAS4 for queuing. This is the how Invincible-class CVS as a ASW carrier did with SeaKing, (and Ocean do, as well as QE will do with Merlin HM2) their ASW tasks.

Lastly, even if it can, do the T45s regularly embark a Merlin? I thought they mostly carried the Wildcats?

To my understanding, T45 have never deployed with Merlin embarked. Always a Wildcat or 2 Wildcats.

Hope this will help you...

[shark bait]

The simple answer is no.

The sonar system on a T45 likely has an effective range lower than a modern heavy weight torpedo. To be truly effective it would have to keep that Merlin in the air constantly, which isn't realistic.

The Merlin/T23 combo is so successful because the frigate spends days towing its sonar and probing a contact. Once they are reasonably confident its a hostile contact they send the Merlin out to localize, and if required prosecute the target. In that situation the Merlin is only used in the short final stages.

To be simple, ASROC is a good pair with a Hull sonar, and helicopter is a good pair with a towed sonar. Only the helicopter and towed sonar has an effective range well beyond the reach of the subs weaponry, which is why the T26 wont have torpedo tubes fitted.

I don't believe the T45 deploys ever with a Merlin, it will have to deploy with a wildcat because that is soon to be the only anti ship weapon in the RN.

[dmereifield]

Thanks Donald,

From my limited reading I understand that this approach works for the carriers because they can carry sufficient airframes to provide a bubble of protection, and ensure 24hr coverage through rotating the airframes. Clearly this is not the case for the T45, so a T45 will likely have partial protection for X hours per day, assuming good weather conditions. Doesn't sound too promising if the T45 is on singleton deployments, even less so considering your comments that they only carriy the wildcat anyway....

[dmereifield]

Thanks for the additional info SB. Hopefully the T26 will have ASROC, still hoping that the T31 might too....but I know I'm being overly optimistic on that one...

[shark bait]

I'm not sold on ASROC, it's effective range is still well within the kill zone of a capable sub. Its a dated system from the time when hull sonars were king.

I can understand the appeal, perhaps there is a requirement for something that can react quickly to a pop up threat, but it would have to be a new system to be valuable. I would like to explore the possibility of cold launching a winged torpedo from the CAMM silos. It would only be a small yield weapon, but that may be enough. I understand a subs usual reaction to hearing the plop of sonobuoys or torpedo's is to run and make a new approach.

[shark bait]

Donald mentions the ship-turpedo-defence-system, part of that is essentially a simple towed array. The Americans are replacing one of the towed decoys on their destroyers with a more advanced multi-function-towed array, which improves the chances of detecting a sub.

The same could be fitted to the T45, making it more effective at finding subs, and would make working along side a Merlin more realistic. I would advocate a similar system for the T45, more nodes in the water around the carrier to direct the Merlin must be a good thing.

The T45 is not made for singleton deployments, its sole purpose is fleet defense where it has other supporting ASW assets, so its own ASW deficiencies are not critical weaknesses.

[ArmChairCivvy]

I'm not sold on ASROC, it's effective range is still well within the kill zone of a capable sub. Its a dated system from the time when hull sonars were king.

Exactly. But with enough of ASROC-kitted (hull-sonared?) ships you can form an outer ring (a diamond, to be maximally separated from each others noises?) to defend the HVUs, should the detection of subs, and then pursuit by helos, further out prove not to be 100% effective.

[donald_of_tokyo]

I'm not sold on ASROC, it's effective range is still well within the kill zone of a capable sub. Its a dated system from the time when hull sonars were king.

RUM-139 VL-ASROC has a range of 12 nm (22 km). A torpedo launched 12 nm away with fastest speed of 50 knots (or cruise speed of 30 knots) needs 14 (or 24) minutes to reach your escort. The escort can do maneuver and be 6-12 nm (or 10-20 nm) away from the assumed location, while putting a decoy at the middle. Of course, the 50 knot torpedo cannot use sonar, so it needs mother-sub's wired-guidance. Even a 30 knot torpedo also has no chance to detect escorts from 12 nm away if it keeps silent (anyway small sonar they have), so anyway wire-guidance from mother sub is MUST, I think. If you can attack mother sub with VL-ASROC at 12 nm max-range, I think it will work.

But, then, sub will launch 3-4 torpedoes in an arc covering ~10nm wide area, if the sub wants to cut the wire and go away and hide. Then, at least 1 torpedo will reach your escort, and she needs to do some dancing maneuver with towed decoy to get rid of it. Thus, ship-torpedo-defence-system, or anti-torpedo decoy technology is very important. (In 1980-2000, it was the famous NIXIE (AN/SQL-25) decoys).

Anyway, torpedo has limited sonar, so soft-kill must be efficient, if properly funded/tested/modified and equipped.

[dmereifield]

The T45 is not made for singleton deployments, its sole purpose is fleet defense where it has other supporting ASW assets, so its own ASW deficiencies are not critical weaknesses.

But in the absence of a fleet to defend (with the CVs retired), and dwindling surface warships, they have been used as singletons haven't they? Or, at least, travelled long distances on their own to meet with allied fleets. Surely they are somewhat vulnerable under such circumstances(?).
Given this, and the low numbers of other vessels, it would surely be desirable to increase their utility (e.g. Fitting the MK41 and adding ASROC and LRASM)

[ArmChairCivvy]

A torpedo launched 12 nm away with fastest speed of 50 knots (or cruise speed of 30 knots) needs 14 (or 24) minutes to reach your escort.

Hmmm, the faster torpedo was originally developed to hit incoming ones. But:

"The VA-111 is launched from 533 mm torpedo tubes at 50 knots (93 km/h) before its solid-fuel rocket ignites and propels it to speeds of 200 knots (370 km/h). Some reports indicate that speeds of 250+ knots may be achieved, and that work on a 300-knot (560 km/h) version was underway.[wiki says]"

Further [from the same souce]: there are 2-3 more versions of it
"Shkval 2" - Current variant; believed to have additional guidance systems, possibly via the use of vectored thrust, and with much longer range.
A less capable version currently being exported to various third world navies. The export version is referred to as "Shkval-E".
Iran claimed it has created a version named Hoot.

[donald_of_tokyo]

"The VA-111 is launched from 533 mm torpedo tubes at 50 knots (93 km/h) before its solid-fuel rocket ignites and propels it to speeds of 200 knots (370 km/h). Some reports indicate that speeds of 250+ knots may be achieved, and that work on a 300-knot (560 km/h) version was underway.[wiki says]"

Interesting. Of course, no sonar can be used with this speed. So its guidance just is INS = it is just like torpedo attacks in WW2, but with more fast speed. VA-111 Shkval-2's range 11-15 km and 250 knots for 15 km is 2 minutes. With no sensor in VA-111, proper maneuver of the escort is the key. Also, out-ranging the Sub (with VL-ASROC with 22km range) will be another good solution, if can be detected.

[ArmChairCivvy]

As our friends from St. Pete edit the wiki and interrogate this site... we can go in circles [obviously the circles will have to be slow enough, not to be detected]

Hopefully your calculus now has the sensitivity analysis added:
- speed: higher?
- range: longer?
- final approach homing head? (could be just fiction; you decide, for your next round)

[marktigger]

I don't believe the T45 deploys ever with a Merlin, it will have to deploy with a wildcat because that is soon to be the only anti ship weapon in the RN.

all the more reason to give merlin Air to surface guided weapons and make it a more flexible platform.

Given the dimmensions of flight decks soon most of the fleet will be merlin capable. Type 31 certainly should be so is there any need for wildcat if the govt made another Merlin HM2 buy?

[ArmChairCivvy]

Given the dimmensions of flight decks soon most of the fleet will be merlin capable. Type 31 certainly should be

I think a healthy distinction has been made between decks (Chinook/ Merlin) and hangars (Merlin/ Wildcat).
- what can land, and be refuelled , is one up from the permanent "resident" (if any such carried)

[marktigger]

type 23, 45, 26, wave, tide, fort all merlin capable type 31 should follow suit

[ArmChairCivvy]

26

yep ; did the Chinook capable T26 survive (the design scrutiny)?

[marktigger]

chinook deck but merlin deck/hanger will be on the 26

[seaspear]

The Kilo class submarine often uses the type 53 to 65 wake homing torpedo launched from 11.8 miles and is not wire guided , they can cause serious damage to the rear of a carrier , or any ship.
A Chinese type Kilo was well within this range of the Kitty hawk when it surfaced some years ago , the range of this torpedo is exceeded by Asroc ,
The down time for an escort carrying two Merlins maintenance could prevent 24 hour coverage even reacting to a detection .

[donald_of_tokyo]

The Kilo class submarine often uses the type 53 to 65 wake homing torpedo launched from 11.8 miles and is not wire guided , they can cause serious damage to the rear of a carrier , or any ship.

Do you have more info about this "wake homing"? I read (in Japanese analysis) that wake homing is relatively easy to get rid of, by a simple U-turn, mixing wakes of a few vessels by crossing their wakes one-another, and so on. But, not sure. What I know is not all torpedo uses wake homing, including the newest ones. So, clearly it is not all-mighty, and has some limit. But I admit I do not know what it is.

The down time for an escort carrying two Merlins maintenance could prevent 24 hour coverage even reacting to a detection .

Agreed. Helicopter needs huge maintenance. In Japan, navy says they need 8-units for 24 hour operation (similar to 9-units RN think). But, this includes the searching one always flying. So, I guess, about 4-units, or at least 3-units, will be needed to be "ready on-call 24/7".

[marktigger]

or you have larger rfa's carrying multiple helicopters as was envisaged for the fort victoria class. which if coupled with the t23 as it was built would have provided fairly strong ASW force.

[shark bait]

Helicopter down time is not much of an issue. On the off chance a frigate walks into a critical situation without its Merlin ready there are other options, in the GIUK gap it can call in a P8, in a task group it can call in another helo.

In the area of ASW ops there will be no shortage of aircraft to complement the frigate.

ASW is often dubbed 'awfully-slow-warfare', presumably the chances of being caught off guard without a Helo are low.

[marktigger]

Helicopter down time is not much of an issue. On the off chance a frigate walks into a critical situation without its Merlin ready there are other options, in the GIUK gap it can call in a P8, in a task group it can call in another helo.

In the area of ASW ops there will be no shortage of aircraft to complement the frigate.

ASW is often dubbed 'awfully-slow-warfare', presumably the chances of being caught off guard without a Helo are low.

by the nature of what and how a submarine operates the chances of being caught of guard are Huge as the Argentine navy found out to its cost. Given we also lost a torpedo decoy in an area where the Argentines were operating a type 205 submarine there is every possibility HMS Arrow (i thinkk) could have been caught off guard

[ArmChairCivvy]

Given we also lost a torpedo decoy

How do you lose one? Other than go "bang" - and then you know it has done its job

[marktigger]

Given we also lost a torpedo decoy

How do you lose one? Other than go "bang" - and then you know it has done its job

it was recovered damaged but only speculation as to cause of damage

[Ron5]

Given we also lost a torpedo decoy

How do you lose one? Other than go "bang" - and then you know it has done its job

Towed and the string broke.