FFG 054/054A Thread

[crobato]

That's why you need a lot of helos, taking shifts. Simply said, there are no other better means of detection, other than another sub or SOSUS, before the offending sub gets into its AshM range. What more, if the helo carries ASW light torpedoes, it can proceed to engage the sub, well well beyond the range of the ship's ASW rockets or even ASROC. How much time will it take for a ship to run over a 100km before it can engage the sub? By then the sub would have expended its AshMs to sink the ship, and run away.

Even current ASW is no sure fire against subs even in torpedo range. Just last Valient Shield exercises, one of the LA subs got an A. Burke destroyer on its periscope sights.

 

[adeptitus]

helicopter cannot be operated continuously due to need of maintenance, fuel, pilot fatigue, etc.

That's probably why Japan and Korea went with the flat-top design. The Hyuga and Dokdo class ships can carry up to 10-11 helicopters, so you could rotate them between refueling.

Most modern ASW helicopters have 3-4 hour mission endurance. I think you can probably refuel and prep a helicopter for flight within that time.

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I think some of us evaluate the 054/054A from western perspective, where Frigates were given ASW role and destroyers AAW - the newer EU AAW frigates are actually destroyer sized ships.

Because we don't see TAS/VDS or ASROC system on the 054/054A, we think it's abnormal and debate on this short-coming. I've actually read posts on another forum where people argue that the CY-1 is installed on the frigate. Um... wishing really hard for something to happen is probably not going to make it happen.

If the PLAN had installed a TAS on the 054/054A, we'd probably have seen it above deck or hanging off an opening below-deck by now.

IMO the 054/054A Frigates go into the "General Purpose" category that serves brown/green water navies well, like Malaysian Navy's Leiku class, S. Africa's Valour Class, Indonesian Sigma class, and so on. They have some multi-mission capability, but weren't built to sail across the ocean to hunt Soviet subs. If the PLAN had a pressing need to address submarine threat in blue-water environment, they'd probably have imported the Russian Club ASW missile system.

Come to the think of it... if Taiwan does get its 8 new subs, we might see the PLAN invest heavily in ASW warfare to address the new threat.

 

[crobato]

VDS is probably of limited value in littoral or brown waters. I suspect the omission of VDS/TAS on the 054A is a decision call. VDS and TAS requires a large hinch and lots of wiring to work, and a decision call is made whether all this is advantageous for the expense.

It might be better to build a more dedicated ASW ship, much like the Udaloys. But for that expense, you can also build a dedicated attack sub. Still, an ASW frigate or destroyer makes a better escort "presence" to a carrier group.

As for the Club ASW, I don't think that addressed fully the need for trying to detect a sub at longer distances in the first place.


Ship based active sonar are double edged swords that can betray the ship to a lurking sub. The sub "detects" the ship with the active sonar first and therefore gains the first initiative of attack. Using ASW helos on the other hand, the helo takes the detection risk off the ship, and a sub cannot do much against a flying vehicle.

 

[nemo]

Well, operating a helicopter continuously is expensive, not to mention wear and tear. For peacetime operation, that is probably not feasible.

Traditional tactic is ship sonar is used to detect abnormalities/possible contact, then send the helicopter to investigate. If you don't know when to launch the helicopter,
you have to send it out on patrol around the clock, and that
is not really feasible.


054, because of it's stealthy feature, are suited as a picket. But if you launched a helicopter, that will make your presence known.

 

[crobato]

054 is only stealthy from a radar perspective, but not as a sound perspective. The all diesel approach makes it noisy. A better ASW platform would better use gas or steam turbine, but preferably more on the gas side. Hence no surprise, its a 052 that you see with a TAS/VDS. If you need a better ASW platform you need to work from that line. A future 052X need not be a big destroyer---the Type 52 designation is actually reserved for anything with a gas turbine or CODAG configuration. A smaller, but gas turbine ship that would be acceptably as a "frigate" in size may still be technically considered a Type 52x.

You can't drag a VDS/TAS all day around either, you slow down an entire ship for that which forces you to sacrifice one of the main assets of a ship, its mobility. And if you want persistant detection, try sonar buoys---best dropped from helicopter.

 

[nemo]

Hull mounted sonar also will suffer from vibration issue. TAS is still better off due to the distance from the hull. While the performance may be degraded, it's possible to mitigate it by filtering out known source of noise (i.e. engine).

Pickets typically operate in pairs -- one slows and listen, while the other dash ahead. When the other picket is in place, the listening picket dash ahead while the other picket slows and listen.

 

[crobato]

Whether by filtering and cancellation, the active hull sonar usually is a high frequency one, while the engine and hull sounds would have a different frequency. So you look only for the echoes of the emitted frequency and disregard the rest. And of course, engine sounds can be filtered out. Hull mounted sonar is usually bow mounted sonar, which is faced away from the engine. As TAS is passive it is vulnerable to whatever quieting measures the opposing sub has, but no amount of quieting will stop an active hull sonar from detecting you.

Regardless, current hull/TAS/VDS sonars will not detect a sub at sub fired AshM ranges (at least 100km and over 200km on some). You would need SURTASS like ships and SOSUS like networks.

 

[nemo]

Of course, using active sonar let the enemy know you are there at at least twice the range you are able to detect him. And anechoic tiles reduce active sonar.

As far as missile range exceed sonar range -- it goes both way. Sub's detection range from its own sensor is insufficient to use the full range of the missile also.

 

[crobato]

True but something else can pick up the targets for the subs. And yes the Songs did practice their AshMs with Y-8s finding targets for them.

Here is a list of ships that appear to have rearward openings big enough for use of TAS.

All the Jiangweis.
051B Luhai (yes, and the opening is gone on the 051C).
052,
052B
and 052C.

So the Jiangweis appear to have TAS or the provision for TAS but its gone with all the 054s. Likewise, it is also removed on the 051C while being present on the 051B.

 

[tphuang]

True but something else can pick up the targets for the subs. And yes the Songs did practice their AshMs with Y-8s finding targets for them.

Here is a list of ships that appear to have rearward openings big enough for use of TAS.

All the Jiangweis.
051B Luhai (yes, and the opening is gone on the 051C).
052,
052B
and 052C.

So the Jiangweis appear to have TAS or the provision for TAS but its gone with all the 054s. Likewise, it is also removed on the 051C while being present on the 051B.

i took a look at their behinds, it seems that 051B have the opening large enough for TAS, but not 052B/C imo.

Also, maybe China has already developed conformal Variable depth sonar?