Is a modern Flower class corvette even realistic?

[H_K]

We are getting a bit too off topic on pushing it on commercial owners. Try to to get them to agree first. Historically, they don't because of expenses like insurance, making themselves a target and may not be allowed into port for political reasons etc. I've discussed this too often so let's skip this rabbid hole.

These civilian platforms would be acquired or at a bare minimum requisitioned for wartime duties. I doubt the owners would have much of a say.

There would have to be some kind of draft process for civilian crews who stay onboard, or (ideally) enough foresight to create a reserve pool of civilian mariners before any conflict.

 

[Mk38]

These civilian platforms would be acquired or at a bare minimum requisitioned for wartime duties. I doubt the owners would have much of a say.

There would have to be some kind of draft process for civilian crews who stay onboard, or (ideally) enough foresight to create a reserve pool of civilian mariners before any conflict.

I mean they’d probably just man them with sailors…

Sr LT as CO, jr LT as XO, JGs as department heads, and sr ensigns as divos.

A sr chief, small chiefs mess, 1sts for enlisted leadership. Or whatever the model for the cyclones was if that’s pretty far off.

 

[Scott Kenny]

I mean they’d probably just man them with sailors…

At least the weapons/sensors will have to be military.

You could arguably let civilians operate the ship.

 

[Mk38]

At least the weapons/sensors will have to be military.

You could arguably let civilians operate the ship.

Why would you have civilians operate a warship?
Civilians caught on an armed vessel can be treated as pirates.
Just man them with sailors.

 

[Scott Kenny]

Why would you have civilians operate a warship?
Civilians caught on an armed vessel can be treated as pirates.
Just man them with sailors.

If it's just a sonar ship, it's not an issue.

See the USNS SURTASS ships. Civilian ship operations, military sonar operators and comms.

 

[Mk38]

If it's just a sonar ship, it's not an issue.

See the USNS SURTASS ships. Civilian ship operations, military sonar operators and comms.

It’s a warship meant to hunt, identify and possibly prosecute submarines.

 

[Scott Kenny]

It’s a warship meant to hunt, identify and possibly prosecute submarines.

Remove the "possibly prosecute submarines" part and you have a SURTASS ship.

Nevermind any/all of the various armed merchantmen that happened in WW2 with civilian crews and Navy or USCG gunners.

 

[Mk38]

Remove the "possibly prosecute submarines" part and you have a SURTASS ship.

Nevermind any/all of the various armed merchantmen that happened in WW2 with civilian crews and Navy or USCG gunners.

Yes defensive armament for transports.

A corvette is not a transport.

 

[Scott Kenny]

Yes defensive armament for transports.

A corvette is not a transport.

An 18kt fishing boat or offshore support boat barely counts as a corvette.

 

[Mk38]

An 18kt fishing boat or offshore support boat barely counts as a corvette.

The flower class corvette was literally a whaling ship with some guns and depth charges added on to it. Are you arguing it wasn’t a warship?

And depending on the support boat they can be quite fast. 30+ knots is not uncommon.

What I have described is a ship with sensors to detect and classify submarines, SVTT to prosecute the target, and a gun system to be able to defend against small boats, and subsonic air targets.

Literally just a modernized concept of the WWII flower class corvette.

 

[Not James Stockdale]

The flower class corvette was literally a whaling ship with some guns and depth charges added on to it. Are you arguing it wasn’t a warship?

And depending on the support boat they can be quite fast. 30+ knots is not uncommon.

What I have described is a ship with sensors to detect and classify submarines, SVTT to prosecute the target, and a gun system to be able to defend against small boats, and subsonic air targets.

Literally just a modernized concept of the WWII flower class corvette.

The main problem is that a ship like that is both not enough and not needed. Without a standoff ASW weapon like a helicopter, it can be easily outranged by a heavyweight torpedo, or destroyed by submarine-launched AShMs. The Stalwart class SURTASS ships were operated by MSC, derived from civilian designs, and crewed by a mix of civilian mariners and Navy sensor operators, and they were expected to participate in World War III while entirely unarmed.

The real shortfall is in sea-based, standoff ASW platforms. Two options that could fill that role are a PSV with a helicopter deck and hangar to support an ASW helicopter, or a small USV (maybe an 11 m hull or even smaller) that can carry a single SVTT up to 100 miles from a parent frigate. Both would still require AAW coverage from a real warship, though you might be able to put a CIWS on the PSV. The USV would need to be too small or too numerous to easily target with submarine-launched torpedoes or AShMs, so they could threaten the enemy submarine with a swarm of torpedoes. Neither of these platforms would need their own sonars, and it would really be preferable to have all of the sensors and effectors spread across as many different platforms as possible.

 

[lastdingo]

Without a standoff ASW weapon like a helicopter, it can be easily outranged by a heavyweight torpedo, or destroyed by submarine-launched AShMs.

Yes, THOUGH one might define a modern Flower corvette as an escort that usually or mostly keeps the escorted convoy alive (if at least two escorts are present), NOT as a threat platform killer.

Keeping alive can be done by alerting the convoy in time about a probable submarine contact so said contact can be avoided (run away from) and possibly be dealt with by a MPA.
Add CAPTAS-2 or even only CAPTAS-1 (though that may be optimistic) and multicopters for delivery of LWT (preferably the most lightweight models) and more importantly of sonobuoys (mostly to weed out false contacts) and you should be fine.

Moreover, one might consider the ability to fend off a salvo of up to 40 AShMs with two such escorts as necessary regardless of how close a hostile sub may come. Sub-launched AShMs outrange even CAPTAS-4 and equivalent missiles could even be dropped from airliners.
Defence against said AShMs might - in absence of AEW - happen at no more than radio horizon distance. There's no point in having some 300 km range radar and 150 km range missile against 30k ft altitude targets when threat missiles would approach at 5-10 m and become visible at horizon only. So horizon range against threat missiles at 5-10 m, about double that against higher-flying supersonic missiles. A rotating Thales NS50 (a rotating radar for lower cost) and gimballed optronics sensor coupled with IRIS-T SLMs (relatively cheap horizon-ranged SAM with supposedly good ceiling) and lots and lots of decoy launchers (including containerised on the escorted ships) should work fine.


I think a "Flower corvette 2030" could be had at 2,500 tons and less than 500 million € (and much less than 300 million € if you build 50 in 10 years).

Its design would first and foremost be an exercise in restraint and in leaving trodden paths.

 

[H_K]

Moreover, one might consider the ability to fend off a salvo of up to 40 AShMs with two such escorts as necessary regardless of how close a hostile sub may come.

I don't think a salvo of 40 AShMs is realistic against a civilian convoy. Simply not a good use of a high-value SSGN's capability and expensive missile load... (Against a carrier task force certainly, but that's already a very well defended target)

A typical convoy with 2 corvette escorts (one each side) might be 15-18 ships (3 columns of 5-6). Even if each corvette had only a simple defensive SAM system with 8-12 ready-to-fire missiles (as small as Mistral or IRIS-T SLS/AIM-9X) that should be enough to deal with decent-sized salvos and significantly limit the attacker's ability to dent the convoy.

 

[Foo Fighter]

https://en.wikipedia.org/wiki/Hunt-class_destroyer

As I mentioned before, I thought that the Flowers had been surpassed so the equivalent might better be one of those replacements. Something that development suggested was more not less needed.

 

[Mk38]

The main problem is that a ship like that is both not enough and not needed. Without a standoff ASW weapon like a helicopter, it can be easily outranged by a heavyweight torpedo, or destroyed by submarine-launched AShMs. The Stalwart class SURTASS ships were operated by MSC, derived from civilian designs, and crewed by a mix of civilian mariners and Navy sensor operators, and they were expected to participate in World War III while entirely unarmed.

The real shortfall is in sea-based, standoff ASW platforms. Two options that could fill that role are a PSV with a helicopter deck and hangar to support an ASW helicopter, or a small USV (maybe an 11 m hull or even smaller) that can carry a single SVTT up to 100 miles from a parent frigate. Both would still require AAW coverage from a real warship, though you might be able to put a CIWS on the PSV. The USV would need to be too small or too numerous to easily target with submarine-launched torpedoes or AShMs, so they could threaten the enemy submarine with a swarm of torpedoes. Neither of these platforms would need their own sonars, and it would really be preferable to have all of the sensors and effectors spread across as many different platforms as possible.

So…you think a submarine is going to 100% give away its position to launch a missile at a cheap low end ship, so it can then be engaged by helicopters from other larger ships that maybe nearby, or land based MPAs?

 

[Not James Stockdale]

Yes, THOUGH one might define a modern Flower corvette as an escort that usually or mostly keeps the escorted convoy alive (if at least two escorts are present), NOT as a threat platform killer.

Keeping alive can be done by alerting the convoy in time about a probable submarine contact so said contact can be avoided (run away from) and possibly be dealt with by a MPA.
Add CAPTAS-2 or even only CAPTAS-1 (though that may be optimistic) and multicopters for delivery of LWT (preferably the most lightweight models) and more importantly of sonobuoys (mostly to weed out false contacts) and you should be fine.

If your corvette is escorting the convoy, then its sensors aren't actually involved in the hunt for the enemy submarine. The Northern Fleet only has about a dozen SSNs and SSGNs, and it would need most of those for bastion defense of its own SSBNs. Against a half dozen enemy submarines, a barrier patrol on the GIUK gap using aircraft and SURTASS ships is far more efficient than close protection of merchant shipping.

LWTs from surface ships are useless against modern submarines when the submarine can hear a container ship from 100 miles away. There's no reason to pretend that could be an effective tool for self-defense unless you use the LWTs to destroy incoming HWTs. Without a Mk 41 VLS for VL-ASROC or something larger like the Sea Lance, the only way to use them effectively is an offboard launch platform, which could be an ASW helicopter, a UAV (minimum size is likely to be something like the MQ-8 Fire Scout), or a USV carrying the torpedoes.

Moreover, one might consider the ability to fend off a salvo of up to 40 AShMs with two such escorts as necessary regardless of how close a hostile sub may come. Sub-launched AShMs outrange even CAPTAS-4 and equivalent missiles could even be dropped from airliners.
Defence against said AShMs might - in absence of AEW - happen at no more than radio horizon distance. There's no point in having some 300 km range radar and 150 km range missile against 30k ft altitude targets when threat missiles would approach at 5-10 m and become visible at horizon only. So horizon range against threat missiles at 5-10 m, about double that against higher-flying supersonic missiles. A rotating Thales NS50 (a rotating radar for lower cost) and gimballed optronics sensor coupled with IRIS-T SLMs (relatively cheap horizon-ranged SAM with supposedly good ceiling) and lots and lots of decoy launchers (including containerised on the escorted ships) should work fine.

I don't think a salvo of 40 AShMs is realistic against a civilian convoy. Simply not a good use of a high-value SSGN's capability and expensive missile load... (Against a carrier task force certainly, but that's already a very well defended target)

A typical convoy with 2 corvette escorts (one each side) might be 15-18 ships (3 columns of 5-6). Even if each corvette had only a simple defensive SAM system with 8-12 ready-to-fire missiles (as small as Mistral or IRIS-T SLS/AIM-9X) that should be enough to deal with decent-sized salvos and significantly limit the attacker's ability to dent the convoy.

I wouldn't be worried about a huge number of Oniks missiles. Using a Tsirkon or two from long range (100 - 200 miles) against the frigates (or corvettes) before closing to engage the cargo ships with torpedoes would be more efficient, and very few European frigates would have any defense against a quasi-ballistic missile. Unless you deploy AAW frigates and destroyers with every ASW group, then dispersing systems like ASW helicopters is going to preserve more capability during an attack.

Another problem with close escort is the speed. Container ships can sustain 20 - 25 knots, and the only ships both faster than that and large enough to carry helicopters are purpose-built warships (unless the convoy escort is a container ship converted like Atlantic Conveyor). Dropping that requirement by not escorting convoys gives you a lot more flexibility in designing and operating smaller ships and USVs for the ASW role.

So…you think a submarine is going to 100% give away its position to launch a missile at a cheap low end ship, so it can then be engaged by helicopters from other larger ships that maybe nearby, or land based MPAs?

If a submarine and an ASW asset run into each other, it's because one of them knows the other is there. Do you think a submarine attacking a convoy would just not bother engaging the escorts? If so, then there's no reason for the escorts because apparently they can't do anything. If it's not an escort scenario, then the appearance of a sonar-equipped enemy combatant means that the enemy already knows where the submarine generally is, so shooting the first enemy sonar as soon as possible will give the submarine the best odds of breaking contact and escaping before other assets show up. That being said, the first asset to respond to cueing from something like SURTASS is going to be an aircraft or helicopter, so the submarine will already be sunk or escaped by the time any surface ship shows up.

 

[lastdingo]

If your corvette is escorting the convoy, then its sensors aren't actually involved in the hunt for the enemy submarine. The Northern Fleet only has about a dozen SSNs and SSGNs, and it would need most of those for bastion defense of its own SSBNs. Against a half dozen enemy submarines, a barrier patrol on the GIUK gap using aircraft and SURTASS ships is far more efficient than close protection of merchant shipping.

LWTs from surface ships are useless against modern submarines when the submarine can hear a container ship from 100 miles away. There's no reason to pretend that could be an effective tool for self-defense unless you use the LWTs to destroy incoming HWTs. Without a Mk 41 VLS for VL-ASROC or something larger like the Sea Lance, the only way to use them effectively is an offboard launch platform, which could be an ASW helicopter, a UAV (minimum size is likely to be something like the MQ-8 Fire Scout), or a USV carrying the torpedoes.

Aside from any GIUK cordon depending on the concept that those quasi picket ships there survive - which is not for certain:

There are more gaps. A Russian SSN can go under Arctic ice and appear west of southern tip of Greenland. Chinese SSN can appear anywhere once they are silent enough to slip through the 1st island chain.

I did NOT mention torpedo tube-launched LWTs. I mentioned drone-delivered LWTs. Think Malloy T-650 with better batteries. Such multicopters can carry a LWT to 15 km and back now, in future effective radius will be greater than 21" torpedo range in tailchasing cargo 21 kts ships. That's cheaper than ASW missiles, requires no missile launcher and the same multicopter type can instead deploy sonobuoys and act as their radio relay.

MQ-8 is NOT the minimum size.

 

[lastdingo]

I don't think a salvo of 40 AShMs is realistic against a civilian convoy. Simply not a good use of a high-value SSGN's capability and expensive missile load... (Against a carrier task force certainly, but that's already a very well defended target)

A typical convoy with 2 corvette escorts (one each side) might be 15-18 ships (3 columns of 5-6). Even if each corvette had only a simple defensive SAM system with 8-12 ready-to-fire missiles (as small as Mistral or IRIS-T SLS/AIM-9X) that should be enough to deal with decent-sized salvos and significantly limit the attacker's ability to dent the convoy.

There are few escorts, so convoys might be very big, such as dozens of ships. Same OR thing as during WW2.
Remember the PQ convoys and how much effort was made in those PQ battles on both sides.

Mistral has totally insufficient range and I doubt its effectiveness/reliability for technical reasons. IRIS-T SLS and AIM-9X launched from surface at near-zero speed have a poor range as well.
Moreover, IRIS-T SLM appears to be CHEAPER than AIM-9X and has a stellar record against Russian cruise missiles at least over land. (Cheap cruise missiles à la Shaheeds are not to be expected at high seas, no submarine launches them.)

MICA is expensive, Aster even more so. ESSM is expensive as well, dunno for sure about CAMM, but IIRC it's way more expensive than IRIS-T SLM even in its basic version. Even RIM-116 RAM is MORE expensive (more than 2x !) than IRIS-T SLM. AIM-9X is apparently more expensive (and clearly less capable) than IRIS-T SLM as well.

So IRIS-T SLM appears to be the sweet spot for air defence out to horizon against 'proper' cruise missiles now, by a big margin. (This assumes that it's going to prove itself against sea skimmers and supersonic AShMs incl. in sea skimming mode during trials for the F125 upgrade).

For the record; what I saw indicated IRIS-T SLM prices of about 250k € to 650k €. I assume the cost per copy (kinda fly away, not all things included) is about 450 k €. Its competitors start at about 900k €, some are at 2 million €.

 

[Not James Stockdale]

Aside from any GIUK cordon depending on the concept that those quasi picket ships there survive - which is not for certain:

There are more gaps. A Russian SSN can go under Arctic ice and appear west of southern tip of Greenland. Chinese SSN can appear anywhere once they are silent enough to slip through the 1st island chain.

I did NOT mention torpedo tube-launched LWTs. I mentioned drone-delivered LWTs. Think Malloy T-650 with better batteries. Such multicopters can carry a LWT to 15 km and back now, in future effective radius will be greater than 21" torpedo range in tailchasing cargo 21 kts ships. That's cheaper than ASW missiles, requires no missile launcher and the same multicopter type can instead deploy sonobuoys and act as their radio relay.

MQ-8 is NOT the minimum size.

The question of getting cargo ships across the Pacific is vastly different than the North Atlantic. The size of the Pacific makes it much easier for Chinese and Russian submarines there to avoid contact than the GIUK gap. The pickets can work better in relatively constrained waters like the gap and the Labrador Sea. I don't think it would be exceptionally difficult to extend the picket coverage to the Labrador Sea, though the sea ice situation would make surface and air prosecution much more complicated.

Out in the Pacific, your light corvette idea makes a lot more sense simply because you need a 2,000 ton ship that can carry a helicopter and keep up with container ships. If you're going to have a ship that can sustain 20 knots for trans-oceanic ranges, then ASW helicopters or large UAVs like the Fire Scout give you a lot more capability than something like the T-650. That would be a better application for a 40 - 60 meter mid-ocean picket that might only be irregularly manned. If the vessel is unmanned, you could have a multicopter armed and sitting in a weather-proof box on the deck of something like the XV Patrick Blackett. Maybe you would need to launch one with a torpedo and one with sonobuoys and a Starlink antenna to feed data back to a land station for final localization of the target.

 

[T. A. Gardner]

In the case of a convoy, I'd think an SSN captain would want to sink the convoy and evade the escorts. Attacking from surprise is his best bet and the convoy is the target, not the escorts. Sinking an escort or two only gets the convoy trying to evade further attack while the remaining escorts are now all over you trying to find and sink you.

Better to get a couple of the convoy ships and then get the hell out of Dodge so-to-speak, than poke the hornet's nest and get an escort ship that can be replaced while missing out on the prize entirely.

 

[lastdingo]

(...) give you a lot more capability than (...)

That's not the topic. You display a lack of intellectual self-restraint and focus here.

This is a thread about modern Flower class corvettes/escorts, NOT for the all-too usual undisciplined thinking about gold plated stuff.

Its design would first and foremost be an exercise in restraint and in leaving trodden paths.

 

[T. A. Gardner]

The question of getting cargo ships across the Pacific is vastly different than the North Atlantic. The size of the Pacific makes it much easier for Chinese and Russian submarines there to avoid contact than the GIUK gap. The pickets can work better in relatively constrained waters like the gap and the Labrador Sea. I don't think it would be exceptionally difficult to extend the picket coverage to the Labrador Sea, though the sea ice situation would make surface and air prosecution much more complicated.

Out in the Pacific, your light corvette idea makes a lot more sense simply because you need a 2,000 ton ship that can carry a helicopter and keep up with container ships. If you're going to have a ship that can sustain 20 knots for trans-oceanic ranges, then ASW helicopters or large UAVs like the Fire Scout give you a lot more capability than something like the T-650. That would be a better application for a 40 - 60 meter mid-ocean picket that might only be irregularly manned. If the vessel is unmanned, you could have a multicopter armed and sitting in a weather-proof box on the deck of something like the XV Patrick Blackett. Maybe you would need to launch one with a torpedo and one with sonobuoys and a Starlink antenna to feed data back to a land station for final localization of the target.

The big issue in the Pacific would be for the ship to have sufficient range to make the trip unrefueled--preferably.

 

[Not James Stockdale]

That's not the topic. You display a lack of intellectual self-restraint and focus here.

This is a thread about modern Flower class corvettes/escorts, NOT for the all-too usual undisciplined thinking about gold plated stuff.

Before you try to blow up at me, why don't you figure out what escorting and anti-submarine warfare look like in the real world. The only reason to have a close convoy escort is for air defense. Using a passive sonar anywhere near a convoy of container ships going 20 knots is impossible and using an active sonar is only going to increase the signature even more. Barrier defense, either with seabed hydrophones or SURTASS ships backed up by frigates, MPAs, and USV pickets, is the best way to get cueing so targets can be localized, prosecuted, and engaged.

You already proposed a 2,500 ton, €500 million ship with a towed array and an air defense system. That is not a small, cheap combatant for any navy. Coincidentally, it is about the minimum size ship you would need to accompany container ships across a 4,000 nm transit at 20 knots. The idea that you would invest these kinds of resources in an anti-submarine focused ship that large and then cheap out by not providing the single most effective ASW tool that surface combatants can carry - a helicopter - is absurd beyond belief.

Based on the size and cost specifications you provided, you could be looking at ships like the Sigma 105, Gowind 2500, or Sa'ar 6. All of these are between 2,000 and 3,000 tons, cost around $500 million, have better air defense systems than what you talked about, and they all have hangars to carry a helicopter. You might get unit costs closer to €250 million with something closer in size and capability to a Type 056 corvette, but that smaller size starts to risk the ship's ability to keep up with container ships while still being large enough to accommodate an extensible hanger for something like a DASH. There is absolutely no reason to accept the degraded capability and range of battery-powered multicopters on a ship this large.

To make sure you didn't miss anything: ASW escorts aren't an actual requirement, hunter-killer tactics are superior to close escort, and your ideas about the size, cost, and capability of an escort corvette make little sense.

The big issue in the Pacific would be for the ship to have sufficient range to make the trip unrefueled--preferably.

You have great circle distances like 4,000 miles from Guam to Hawaii and 6,000 miles from Tokyo to California, and those distances don't include diversions, zigzagging, or maneuvering around the convoy at full speed. You don't want a warship to ever be running on fumes, so I don't think any modern warships can reasonably keep up with container ships over those distances. The closest I have seen would be the Asagiri class destroyers, which supposedly have a range of 6,000 nm at 20 knots.

 

[Mk38]

In the case of a convoy, I'd think an SSN captain would want to sink the convoy and evade the escorts. Attacking from surprise is his best bet and the convoy is the target, not the escorts. Sinking an escort or two only gets the convoy trying to evade further attack while the remaining escorts are now all over you trying to find and sink you.

Better to get a couple of the convoy ships and then get the hell out of Dodge so-to-speak, than poke the hornet's nest and get an escort ship that can be replaced while missing out on the prize entirely.

Right when have subs ever targeted the small escorts? Sure if a cruiser or BB were in the escort historically a sub may target them, but not corvettes, frigates or destroyers

 

[Mk38]

The big issue in the Pacific would be for the ship to have sufficient range to make the trip unrefueled--preferably.

That would be nice, but not not necessary there are several points where the convoy could come in close to places like Hawaii (from CONUS) midway, wake, Guam, etc. where an UNREP ship could sail out under protection of MPA and helicopters to conduct RAS with the escorts.