New USN PC idea

[johnpjones1775]

How long ago was that?

'11 and again in '14

 

[H_K]

why not at least have the option of trading that OPV for that enemy corvette or larger ship?

Fair enough. You could probably fit a 2-4 round NSM launcher amidships on the Ocean Eagle, in lieu of the optional shelter (only 2-4 tons weight).

Move the UAV landing deck to the stern above the RHIB for air surveillance & targeting. The gun above the bridge could be a 30mm chain gun + 2-4 round Stinger launcher (like on the Madis Mk1 JLTVS) for self-defense against small craft, drones and missiles.

That would be the making of a decent *very small* ~75 ton patrol boat.

 

[Jimmo952]

After the fall of the USSR there should have been a decade focused on PCs/OPVs and MCMs, especially after 9/11. A terrorist organization getting ahold of mines and a few dhows were a much bigger maritime threat than any air attack from 2001-2011.

In a way this happened. The LCS was conceived as a way to do those shallow water missions you elude to.

The intent was there. We just chose the most complicated and ultimately expensive way to take on those missions. And we blew it badly.

Anti swarm defense, MIW, shallow water ASW, ...

Those were all supposed to be handled by LCS.

Unfortunately, LCS never quite worked out.


Now, so many years and dollars later, the Navy's attention has been redirected to blue water and China.

Let's hope things don't turn hot in the Gulf anytime soon.

 

[johnpjones1775]

why not at least have the option of trading that OPV for that enemy corvette or larger ship?

Fair enough. You could probably fit a 2-4 round NSM launcher amidships on the Ocean Eagle, in lieu of the optional shelter (only 2-4 tons weight).

Move the UAV landing deck to the stern above the RHIB for air surveillance & targeting. The gun above the bridge could be a 30mm chain gun + 2-4 round Stinger launcher (like on the Madis Mk1 JLTVS) for self-defense against small craft, drones and missiles.

That would be the making of a decent *very small* ~75 ton patrol boat.

you could easily fit 4 on it by putting 2 on each wing between the superstructure and pontoons

 

[johnpjones1775]

In a way this happened. The LCS was conceived as a way to do those shallow water missions you elude to.

The intent was there. We just chose the most complicated and ultimately expensive way to take on those missions. And we blew it badly.

Anti swarm defense, MIW, shallow water ASW, ...

Those were all supposed to be handled by LCS.

Unfortunately, LCS never quite worked out.


Now, so many years and dollars later, the Navy's attention has been redirected to blue water and China.

Let's hope things don't turn hot in the Gulf anytime soon.

i mean the LCS is working out now. just not as advertised.

yes that's how the LCS was supposed to be, but the USN couldn't imagine investing in any true small combatants (and still cant imagine it as it is.) and built a heavy corvette/under armed light frigate.

how they didn't know water jets would make it impossible to do ASW i don't know.

 

[Jimmo952]

i mean the LCS is working out now. just not as advertised.

yes that's how the LCS was supposed to be, but the USN couldn't imagine investing in any true small combatants (and still cant imagine it as it is.) and built a heavy corvette/under armed light frigate.

how they didn't know water jets would make it impossible to do ASW i don't know.

Back when the LCS was conceived, the Navy wanted a shallow water ship that could self-deploy, be very fast and be aviation capable...oh...and have very low manning requirements.

Those requirements drove the hull form, size, power plant and propulsion (water jets).

The Navy correctly saw the need for a shallow water combatant but couldn't help but piling on the requirements.

In retrospect, building a PC replacement should have been a straightforward and fairly low cost affair.

 

[H_K]

So here's my upgunned 80-ton PC, derived from the Ocean Eagle... don't think you can go much smaller than this.

2-4 NSM missiles (could be replaced by loitering munitions)
30mm chain gun + 2-4x Stingers (Madis Mk1 RWS for protection against small craft, UAVs and missiles)
2x 0.50 cal machine guns
1x 6.5m RHIB
1x light UAV or VTUAV
Lightweight towed sonar for ASW detection

30 knots
3,000nm @ 18 knots, 5,000 nm @ 12 knots
15 crew

 

[Hood]

Worried about little boat swarms? You need some of these...

 

[johnpjones1775]

i mean the LCS is working out now. just not as advertised.

yes that's how the LCS was supposed to be, but the USN couldn't imagine investing in any true small combatants (and still cant imagine it as it is.) and built a heavy corvette/under armed light frigate.

how they didn't know water jets would make it impossible to do ASW i don't know.

Back when the LCS was conceived, the Navy wanted a shallow water ship that could self-deploy, be very fast and be aviation capable...oh...and have very low manning requirements.

Those requirements drove the hull form, size, power plant and propulsion (water jets).

The Navy correctly saw the need for a shallow water combatant but couldn't help but piling on the requirements.

In retrospect, building a PC replacement should have been a straightforward and fairly low cost affair.

Well the whole reason the ASW module failed is because of the water jets being too loud and too powerful.

But like I said the USN hates small vessels and LCS is about as small as they could bring themselves to build

 

[johnpjones1775]

Worried about little boat swarms? You need some of these...
View attachment 701486

Oh yeah? How long can that helicopter stay on station?

 

[H_K]

Well the whole reason the ASW module failed is because of the water jets being too loud and too powerful.

No. The USN wanted a large, powerful VDS sonar, but LCS didn’t have the payload carrying ability to handle Captas 4, which also probably was penalized for not being American. So people got the bright idea to design an entirely new, 100% American, lightweight but high performance sonar system, which failed to work.

Basically this is the same thing that happened to the Mone Warfare module… history repeating itself. The fundamental problem was LCS was actually too small to do what was asked of it (and too much payload was traded for the speed requirement).

 

[Jimmo952]

Worried about little boat swarms? You need some of these...
View attachment 701486

Oh yeah? How long can that helicopter stay o

i mean the LCS is working out now. just not as advertised.

yes that's how the LCS was supposed to be, but the USN couldn't imagine investing in any true small combatants (and still cant imagine it as it is.) and built a heavy corvette/under armed light frigate.

how they didn't know water jets would make it impossible to do ASW i don't know.

Back when the LCS was conceived, the Navy wanted a shallow water ship that could self-deploy, be very fast and be aviation capable...oh...and have very low manning requirements.

Those requirements drove the hull form, size, power plant and propulsion (water jets).

The Navy correctly saw the need for a shallow water combatant but couldn't help but piling on the requirements.

In retrospect, building a PC replacement should have been a straightforward and fairly low cost affair.

Well the whole reason the ASW module failed is because of the water jets being too loud and too powerful.

But like I said the USN hates small vessels and LCS is about as small as they could bring themselves to

Both are true. LCS is not small but it's basically a giant speedboat. Payload was sacrificed for speed.

Water jets were found to be a problem also.

The Navy concluded that the LCS would never make a good ASW platform and punted.

 

[Scott Kenny]

LCS design specs had two problems:

1) 40+ knot required speed

2) Not using the already existing STANFLEX modules.

 

[johnpjones1775]

Well the whole reason the ASW module failed is because of the water jets being too loud and too powerful.

No. The USN wanted a large, powerful VDS sonar, but LCS didn’t have the payload carrying ability to handle Captas 4, which also probably was penalized for not being American. So people got the bright idea to design an entirely new, 100% American, lightweight but high performance sonar system, which failed to work.

Basically this is the same thing that happened to the Mone Warfare module… history repeating itself. The fundamental problem was LCS was actually too small to do what was asked of it (and too much payload was traded for the speed requirement).

Not sure what you’re talking about with the MCM module since it’s being installed in the freedoms now, for operations in the gulf.

I’m getting my info from a former LCS dept head, but whatever you say.

 

[Scott Kenny]

Well the whole reason the ASW module failed is because of the water jets being too loud and too powerful.

No. The USN wanted a large, powerful VDS sonar, but LCS didn’t have the payload carrying ability to handle Captas 4, which also probably was penalized for not being American. So people got the bright idea to design an entirely new, 100% American, lightweight but high performance sonar system, which failed to work.

Basically this is the same thing that happened to the Mone Warfare module… history repeating itself. The fundamental problem was LCS was actually too small to do what was asked of it (and too much payload was traded for the speed requirement).

Not sure what you’re talking about with the MCM module since it’s being installed in the freedoms now, for operations in the gulf.

I’m getting my info from a former LCS dept head, but whatever you say.

Right. MCM only took how long to develop? 15 years?

 

[johnpjones1775]

Well the whole reason the ASW module failed is because of the water jets being too loud and too powerful.

No. The USN wanted a large, powerful VDS sonar, but LCS didn’t have the payload carrying ability to handle Captas 4, which also probably was penalized for not being American. So people got the bright idea to design an entirely new, 100% American, lightweight but high performance sonar system, which failed to work.

Basically this is the same thing that happened to the Mone Warfare module… history repeating itself. The fundamental problem was LCS was actually too small to do what was asked of it (and too much payload was traded for the speed requirement).

Not sure what you’re talking about with the MCM module since it’s being installed in the freedoms now, for operations in the gulf.

I’m getting my info from a former LCS dept head, but whatever you say.

Right. MCM only took how long to develop? 15 years?

And? ASW module was dropped, and MCM module is in service. The same thing didn’t happen to the two of them.

 

[Scott Kenny]

Well the whole reason the ASW module failed is because of the water jets being too loud and too powerful.

No. The USN wanted a large, powerful VDS sonar, but LCS didn’t have the payload carrying ability to handle Captas 4, which also probably was penalized for not being American. So people got the bright idea to design an entirely new, 100% American, lightweight but high performance sonar system, which failed to work.

Basically this is the same thing that happened to the Mone Warfare module… history repeating itself. The fundamental problem was LCS was actually too small to do what was asked of it (and too much payload was traded for the speed requirement).

Not sure what you’re talking about with the MCM module since it’s being installed in the freedoms now, for operations in the gulf.

I’m getting my info from a former LCS dept head, but whatever you say.

Right. MCM only took how long to develop? 15 years?

And? ASW module was dropped, and MCM module is in service. The same thing didn’t happen to the two of them.

Right. A whole new set of modules created from scratch, when STANFLEX existed and had all the different modules the USN wanted already developed.

 

[Arjen]

Just as a reminder, @BB1984 's speculation why Stanflex wasn't adopted for LCS, from last year:

https://www.secretprojects.co.uk/threads/littoral-combat-ship-freedom-independence.6234/page-16#post-525841

My theory is that the LCS was, first and foremost, designed to be politically acceptable within the Navy, which meant not only was it was designed for missions no established community (air, surface warfare, submarine) wanted:

• shallow water ASW
• mine clearance
• fighting small boat swarms

. . . but also that it was designed for only those three roles. It was critical that the LCS could not be seen as being in competition with any of the three communities pet, gold-plated, projects. This meant that not only did all 'on ship' armament have to be very short ranged and weak, it also had to mean that it was impossible to upgrade that armament into an alternative to "real" ships (or aircraft), thus Stanflex, or even any "invented here" equivalent, was off the table.

Stanflex offered more flexibility than the US Navy could stomach?

 

[johnpjones1775]

Just as a reminder, @BB1984 's speculation why Stanflex wasn't adopted for LCS, from last year:

https://www.secretprojects.co.uk/threads/littoral-combat-ship-freedom-independence.6234/page-16#post-525841

My theory is that the LCS was, first and foremost, designed to be politically acceptable within the Navy, which meant not only was it was designed for missions no established community (air, surface warfare, submarine) wanted:

• shallow water ASW
• mine clearance
• fighting small boat swarms

. . . but also that it was designed for only those three roles. It was critical that the LCS could not be seen as being in competition with any of the three communities pet, gold-plated, projects. This meant that not only did all 'on ship' armament have to be very short ranged and weak, it also had to mean that it was impossible to upgrade that armament into an alternative to "real" ships (or aircraft), thus Stanflex, or even any "invented here" equivalent, was off the table.

Stanflex offered more flexibility than the US Navy could stomach?

I’d have to disagree agree with his characterization of LCS weapons as being ‘weak’

I don’t believe it’s been published publicly, but an LCS has defeated a burke in exercises. (While not publicly published it isn’t a classified exercise. At least I hope not for my buddy’s sake)

 

[johnpjones1775]

Well the whole reason the ASW module failed is because of the water jets being too loud and too powerful.

No. The USN wanted a large, powerful VDS sonar, but LCS didn’t have the payload carrying ability to handle Captas 4, which also probably was penalized for not being American. So people got the bright idea to design an entirely new, 100% American, lightweight but high performance sonar system, which failed to work.

Basically this is the same thing that happened to the Mone Warfare module… history repeating itself. The fundamental problem was LCS was actually too small to do what was asked of it (and too much payload was traded for the speed requirement).

Not sure what you’re talking about with the MCM module since it’s being installed in the freedoms now, for operations in the gulf.

I’m getting my info from a former LCS dept head, but whatever you say.

Right. MCM only took how long to develop? 15 years?

And? ASW module was dropped, and MCM module is in service. The same thing didn’t happen to the two of them.

Right. A whole new set of modules created from scratch, when STANFLEX existed and had all the different modules the USN wanted already developed.

Ok? That’s irrelevant and obsessing over the USN not going that route is just living in the past and doesn’t do anyone any good.

 

[Arjen]

I'd have to disagree agree with his characterization of LCS weapons as being ‘weak’

'Weak' is exactly the characterization I would use when comparing the armament of the Freedom- and Independence-classes with the possible armament offered by Stanflex-modules. In 2007 Stanflex offered (not an exhaustive list)
- 76mm OTO Melara rapid-fire gun
- VLS for Sea Sparrow / Evolved Sea Sparrow
- Harpoon
- Thales Salmon 2640 VDS
- MCM module
- MU90 Impact torpedoes
The list has grown. One of the latest options is an SM-2 Block III module on Niels Juel.

obsessing over the USN not going that route is just living in the past and doesn’t do anyone any good.

Learn from your mistakes, or repeat them. If you survive.

 

[Scott Kenny]

I'd have to disagree agree with his characterization of LCS weapons as being ‘weak’

'Weak' is exactly the characterization I would use when comparing the armament of the Freedom- and Independence-classes with the possible armament offered by Stanflex-modules. In 2007 Stanflex offered (not an exhaustive list)
- 76mm OTO Melara rapid-fire gun
- VLS for Sea Sparrow / Evolved Sea Sparrow
- Harpoon
- Thales Salmon 2640 VDS
- MCM module
- MU90 Impact torpedoes
The list has grown. One of the latest options is an SM-2 Block III module on Niels Juel.

obsessing over the USN not going that route is just living in the past and doesn’t do anyone any good.

Learn from your mistakes, or repeat them. If you survive.

The 57mm actually throws a greater weight of shell per minute than any gun short of the 5". Makes it quite effective for local self defense. Though personally I would have preferred a 5" gun on the bow and a pair of 57mm in place of the 30mm in the ASuW modules.

 

[Arjen]

OTO Melara 76mm SR: 120 rounds/min - max range, dependent on shell type, 16-20 km, shell weight ~6 kg
BAe-Bofors 57mm L/70: 220 rounds/min - max range, HE shell, 8.5-17km, shell weight ~2.5 kg
I would say they are are in the same league, with the 76mm having the ability to fire rocket-assisted guided shells at roughly double the range.

The Danish Navy is considering fitting 127mm guns to the Iver Huitfeldt-class, I am unsure whether that would be a Stanflex module.

Navy politics aside, Stanflex looks like a missed opportunity for LCS.

 

[johnpjones1775]

I'd have to disagree agree with his characterization of LCS weapons as being ‘weak’

'Weak' is exactly the characterization I would use when comparing the armament of the Freedom- and Independence-classes with the possible armament offered by Stanflex-modules. In 2007 Stanflex offered (not an exhaustive list)
- 76mm OTO Melara rapid-fire gun
- VLS for Sea Sparrow / Evolved Sea Sparrow
- Harpoon
- Thales Salmon 2640 VDS
- MCM module
- MU90 Impact torpedoes
The list has grown. One of the latest options is an SM-2 Block III module on Niels Juel.

obsessing over the USN not going that route is just living in the past and doesn’t do anyone any good.

Learn from your mistakes, or repeat them. If you survive.

LCSes get NSMs which out classes harpoon.
Mk110 is a much better weapon for the intended uses of these ships.

So again calling the armament weak is silly.

And there’s a massive difference between learning from mistakes and obsessing over them.
Learning “this is what we should have done and what we should do in the future.” And following through.

Obsessing preventing any meaningful discussion from occurring by constantly bring up the mistake(s)

 

[Arjen]

You are missing the point. Stanflex offers even more flexibility in VLS Mk41 modules, which in themselves can be used for SM-2 Block III through Tomahawk through JSM. <edit>Retracted on reading later comments. I conflated VLS Mk48 with VLS Mk41. VLS Mk 41 is indeed a non-Stanflex installation.</edit>
If you are proposing small warships, modular armament has found its way to the 320 tonne Flyvefisken-class.
Stanflex Harpoon-modules were operational in 2007, when LCS was walking baby steps. Things have moved on.

the intended uses of these ships

A case of chicken and egg. LCS-roles are limited by their equipment.

 

[A Tentative Fleet Plan]

The list has grown. One of the latest options is an SM-2 Block III module on Niels Juel.

You are missing the point. Stanflex offers even more flexibility in VLS Mk41 modules, which in themselves can be used for SM-2 Block III through Tomahawk through JSM.

The SM-2s and Tomahawks on the Iver Huitfeldt-class are launched from the Mk 41 VLS, not from the Stanflex Modules, which do not have the depth of the VLS cells.

 

[TomS]

Stanflex was never seriously considered for LCS, for a couple of reasons.

One is that the Stanflex box was too small and too optimized for dropping though a hole in the deck. A lot of the systems planned for LCS (from the Remote Minehunting System vehicle to USVs based on 11-m RHIBs to large VDS and towed array sonars) were too big to fit in a STANFLEX-style module. They were going to live in a mission bay (hangar) under the helicopter deck anyway, so it made sense to put the rest of their support systems into boxes that could also fit in a mission bay and easily roll on and off the ship -- which meant ISO 20-foot containers. These also had the advantage of being easily trailerable and air-transportable, which fit the narrative of being able to transport new modules to forward areas and swap them out on the fly.

That left only the gun and missile modules that could potentially have fit in STANFLEX modules. But the USN wanted someting with a bit more space, so we get the new LCS modules (which are really hard to find precise dimensions for. I thought we had them here somewhere, but I can't find them).

But the real problem with LCS wasn't the size or standard for the modules, it was the mission equipment that went inside them. Getting the sonars, USVs, UUVs, etc to work up to the required spec has been the development nightmare. Stuffing the equipment into STANFLEX modules instead of ISO boxes would not have changed that in the slightest.

 

[johnpjones1775]

Can we now move on from the stanflex distraction?

 

[TomS]

Can we now move on from the stanflex distraction?

Sure:

Here's an example of a minimum ASW-capable ship, the Indian Navy's ASW Shallow-Water Craft. Displacement is 750-900 tons depending in which version you get. Armament is one 30mm gun, two 12.7mm, one RBU-6000, two triple lightweight torpedo launchers, and sea mines. Sensors are a hull-mounted sonar and a low-frequency VDS. I think that's pretty much the minimum price of admission for credible ASW capability.

 

[johnpjones1775]

Can we now move on from the stanflex distraction?

Sure:

Here's an example of a minimum ASW-capable ship, the Indian Navy's ASW Shallow-Water Craft. Displacement is 750-900 tons depending in which version you get. Armament is one 30mm gun, two 12.7mm, one RBU-6000, two triple lightweight torpedo launchers, and sea mines. Sensors are a hull-mounted sonar and a low-frequency VDS. I think that's pretty much the minimum price of admission for credible ASW capability.

View attachment 701661

What are the ranges on the ASW rockets?

Never seen or heard of this ship class before.

I’d drop the rockets, and 30mm extend that fwd deck a bit and drop either a mk110 in or 4-8 cell VLS for ESSM. Not sure if ASROC would fit in the shortest VLS length or not. If so I’d do 4 cell, 3 ASROC 1 quad packed ESSM.

ESSM can target surface vessels and does pretty serious damage, so you’ve got some self defense capability as well as that offensive ASW option.

Honestly I’d also probably drop one of the sonar systems to save some money and weight.

 

[TomS]

What are the ranges on the ASW rockets?

Never seen or heard of this ship class before.

I’d drop the rockets, and 30mm extend that fwd deck a bit and drop either a mk110 in or 4-8 cell VLS for ESSM. Not sure if ASROC would fit in the shortest VLS length or not. If so I’d do 4 cell, 3 ASROC 1 quad packed ESSM.

ESSM can target surface vessels and does pretty serious damage, so you’ve got some self defense capability as well as that offensive ASW option.

These are new, and INdian, thus not well known in the West (a lot of Indian naval stuff that isnt carriers, frigates or subs flies under the radar).

RBU-6000 range is about 5000 meters max, depending on the rocket.

VLA fits Tactical length launchers but not Self-Defense -- that booster is loooong. Personally I think 4 ESSM doesn't make sense. To guide it at all requires a hefty bit of combat system; and 4 rounds is literally two engagements.

 

[TomS]

Now, if you want to get weird, back in 1976 there was a proposal from the Naval Ship Engineering Center Norfolk Division for a fancy planning hull ASW craft called the "Spirit of '76" (a play on the Bicentennial, the date of the design, and the fact that it was 76 meters [250 feet] long). It displaced about 1100 tons, with 3xLM2500 turbines for a high, but unspecified, top speed.

Spirit made aggressive use of the novel sonar technologies of the era. It had two rocket launchers for Expendable Reliable Acoustic Path sonobuoys (six buoys each, no sign of reloads -- ERAPS buoys would be large and highly capable/expensive). It also carried six expendable linear array sonars (basically small free-floating towed arrays) and had a hull-mounted dipping sonar (helo-style) and a towed array sonar. There were a dozen small RPVs/drones launched from a catapult aft of the superstructure. Armament included eight Harpoons (targeted via RPV), a dozen VLA-like missiles in vertical launchers, a dozen air warfare "standoff" missiles (type unspecified), and six Mk 48 heavyweight torpedoes.

This was a really typical early 1970s hypothetical ASW fit; the same basic systems show up in a couple of Grumman hydrofioil proposals from the same era. More here: https://www.secretprojects.co.uk/threads/grumman-hydrofoil-warship-hyd-2.32080/post-357261 And another one, here: https://www.secretprojects.co.uk/threads/1300-ton-destroyer-escort-hydrofoil-deh.6969/post-356214

Problem is, ERAPS never really worked at the time (it was still a topic of development in the 2000s). Reliable path sonar was one of the holy grail techs for deepwater ASW, sort of a complement to convergence zone sonar.

Source for this is entirely Friedman's US Small Combatants -- I've never found anything else about it anywhere. There are pictures, but they're his drawings, so it seems unfair to reproduce them here.

BTW: early in this thread, PXM was mentioned. We have a short thread on it here -- it's kind of in the ballpark of what you're chasing, decades earlier: https://www.secretprojects.co.uk/threads/pxm-a-modern-subchaser-for-the-usn.41438/

 

[johnpjones1775]

What are the ranges on the ASW rockets?

Never seen or heard of this ship class before.

I’d drop the rockets, and 30mm extend that fwd deck a bit and drop either a mk110 in or 4-8 cell VLS for ESSM. Not sure if ASROC would fit in the shortest VLS length or not. If so I’d do 4 cell, 3 ASROC 1 quad packed ESSM.

ESSM can target surface vessels and does pretty serious damage, so you’ve got some self defense capability as well as that offensive ASW option.

These are new, and INdian, thus not well known in the West (a lot of Indian naval stuff that isnt carriers, frigates or subs flies under the radar).

RBU-6000 range is about 5000 meters max, depending on the rocket.

VLA fits Tactical length launchers but not Self-Defense -- that booster is loooong. Personally I think 4 ESSM doesn't make sense. To guide it at all requires a hefty bit of combat system; and 4 rounds is literally two engagements.

We’re talking about a patrol vessel with some real offensive and defensive capability.

Enough capability that can make an attacker question, is it worth the cost to attack this vessel?

Is it worth it it dedicate roughly half of the ASMs a ship is likely to be carrying to sink a patrol craft, or is it better to hold onto those missiles for a more important target?

Anything more than a 4 cell launcher and you are probably going to need to add a quite a bit more size.

Also sea giraffe can most likely guide them and there are variants that fit onto small assault boats, so you don’t need to have that much extra weight added in order to use the missiles.

 

[H_K]

We’re talking about a patrol vessel with some real offensive and defensive capability.

Enough capability that can make an attacker question, is it worth the cost to attack this vessel?

You need to be more specific about the scenario. Where is this patrol vessel operating and what is it doing? My thoughts:

Scenario 1: Forward deployed in peacetime
Won’t need those ASMs or SAMs any more than the Cyclone class or USCG cutters who do the same job today.

Scenario 2: Defensive ASW patrols in wartime
Will be hundreds or thousands of miles from the forward line of operations. It is not going to come across enemy ship or missile threats, short of a full sortie by a major enemy fleet.

Scenario 3: Operating in a combat zone. Not a job for a patrol boat anymore, but a full-on missile corvette or frigate.

Note that the above hasn’t really changed since WWII, where sub chasers, sloops, and corvettes did one job while destroyers and light cruisers did another. (With late war frigates & destroyer escorts kind of being a general purpose hybrid, similar to a Cold War FFG-7 or 1990s Meko / La Fayette general purpose frigate).

 

[johnpjones1775]

Now, if you want to get weird, back in 1976 there was a proposal from the Naval Ship Engineering Center Norfolk Division for a fancy planning hull ASW craft called the "Spirit of '76" (a play on the Bicentennial, the date of the design, and the fact that it was 76 meters [250 feet] long). It displaced about 1100 tons, with 3xLM2500 turbines for a high, but unspecified, top speed.

Spirit made aggressive use of the novel sonar technologies of the era. It had two rocket launchers for Expendable Reliable Acoustic Path sonobuoys (six buoys each, no sign of reloads -- ERAPS buoys would be large and highly capable/expensive). It also carried six expendable linear array sonars (basically small free-floating towed arrays) and had a hull-mounted dipping sonar (helo-style) and a towed array sonar. There were a dozen small RPVs/drones launched from a catapult aft of the superstructure. Armament included eight Harpoons (targeted via RPV), a dozen VLA-like missiles in vertical launchers, a dozen air warfare "standoff" missiles (type unspecified), and six Mk 48 heavyweight torpedoes.

This was a really typical early 1970s hypothetical ASW fit; the same basic systems show up in a couple of Grumman hydrofioil proposals from the same era. More here: https://www.secretprojects.co.uk/threads/grumman-hydrofoil-warship-hyd-2.32080/post-357261 And another one, here: https://www.secretprojects.co.uk/threads/1300-ton-destroyer-escort-hydrofoil-deh.6969/post-356214

Problem is, ERAPS never really worked at the time (it was still a topic of development in the 2000s). Reliable path sonar was one of the holy grail techs for deepwater ASW, sort of a complement to convergence zone sonar.

Source for this is entirely Friedman's US Small Combatants -- I've never found anything else about it anywhere. There are pictures, but they're his drawings, so it seems unfair to reproduce them here.

BTW: early in this thread, PXM was mentioned. We have a short thread on it here -- it's kind of in the ballpark of what you're chasing, decades earlier: https://www.secretprojects.co.uk/threads/pxm-a-modern-subchaser-for-the-usn.41438/

Yeah the sketch on the first page looks pretty good.
But I’d just replace the flight deck with a small missile deck.
Relying on SVTT is like relying on a .22 derringer.
Put some ASROC in those cells, and at least 1 cell for ESSM and in theory you have a patrol craft that can double as a very light ASW and AAW escort.

 

[johnpjones1775]

We’re talking about a patrol vessel with some real offensive and defensive capability.

Enough capability that can make an attacker question, is it worth the cost to attack this vessel?

You need to be more specific about the scenario. Where is this patrol vessel operating and what is it doing? My thoughts:

Scenario 1: Forward deployed in peacetime
Won’t need those ASMs or SAMs any more than the Cyclone class or USCG cutters who do the same job today.

Scenario 2: Defensive ASW patrols in wartime
Will be hundreds or thousands of miles from the forward line of operations. It is not going to come across enemy ship or missile threats, short of a full sortie by a major enemy fleet.

Scenario 3: Operating in a combat zone. Not a job for a patrol boat anymore, but a full-on missile corvette or frigate.

Note that the above hasn’t really changed since WWII, where sub chasers, sloops, and corvettes did one job while destroyers and light cruisers did another. (With late war frigates & destroyer escorts kind of being a general purpose hybrid, similar to a Cold War FFG-7 or 1990s Meko / La Fayette general purpose frigate).

Cyclones did have ASMs equipped in the form of griffin ASMs, however as I’ve noted I think the cyclones and the FRCs (and their predecessors) are woefully undergunned

A properly armed PC or OPV could fill the same role as a WWII PT boat.

A corvette would fill the same role as well WWII corvettes and DEs.

In the gulf and SCS such vessels will be extremely valuable.

In peace they’d operate alone most likely, in war theyd operate in pairs or trios.

 

[Scott Kenny]

Now, if you want to get weird, back in 1976 there was a proposal from the Naval Ship Engineering Center Norfolk Division for a fancy planning hull ASW craft called the "Spirit of '76" (a play on the Bicentennial, the date of the design, and the fact that it was 76 meters [250 feet] long). It displaced about 1100 tons, with 3xLM2500 turbines for a high, but unspecified, top speed.

Spirit made aggressive use of the novel sonar technologies of the era. It had two rocket launchers for Expendable Reliable Acoustic Path sonobuoys (six buoys each, no sign of reloads -- ERAPS buoys would be large and highly capable/expensive). It also carried six expendable linear array sonars (basically small free-floating towed arrays) and had a hull-mounted dipping sonar (helo-style) and a towed array sonar. There were a dozen small RPVs/drones launched from a catapult aft of the superstructure. Armament included eight Harpoons (targeted via RPV), a dozen VLA-like missiles in vertical launchers, a dozen air warfare "standoff" missiles (type unspecified), and six Mk 48 heavyweight torpedoes.

This was a really typical early 1970s hypothetical ASW fit; the same basic systems show up in a couple of Grumman hydrofioil proposals from the same era. More here: https://www.secretprojects.co.uk/threads/grumman-hydrofoil-warship-hyd-2.32080/post-357261 And another one, here: https://www.secretprojects.co.uk/threads/1300-ton-destroyer-escort-hydrofoil-deh.6969/post-356214

Problem is, ERAPS never really worked at the time (it was still a topic of development in the 2000s). Reliable path sonar was one of the holy grail techs for deepwater ASW, sort of a complement to convergence zone sonar.

Source for this is entirely Friedman's US Small Combatants -- I've never found anything else about it anywhere. There are pictures, but they're his drawings, so it seems unfair to reproduce them here.

BTW: early in this thread, PXM was mentioned. We have a short thread on it here -- it's kind of in the ballpark of what you're chasing, decades earlier: https://www.secretprojects.co.uk/threads/pxm-a-modern-subchaser-for-the-usn.41438/

Heavyweight torpedoes on a surface ship is kinda weird. They're heavy, 3000-3500lbs. A launcher for them is even heavier (no clue how heavy one would be). They waste a lot of time and range diving to the target depth. And you lose out on the wire guidance advantages.

The reason that the Mk46/50/54 (and other countries' equivalents) can be so small is that they're intended to pop the shaft seals on a sub. Do that and you have mobility killed the sub, it's going to have to limp home on the EPM outboards and those are immensely noisy. Assuming that you didn't flood out their engineroom entirely, which will absolutely sink a sub.

 

[Scott Kenny]

We’re talking about a patrol vessel with some real offensive and defensive capability.

Enough capability that can make an attacker question, is it worth the cost to attack this vessel?

You need to be more specific about the scenario. Where is this patrol vessel operating and what is it doing? My thoughts:

Scenario 1: Forward deployed in peacetime
Won’t need those ASMs or SAMs any more than the Cyclone class or USCG cutters who do the same job today.

Scenario 2: Defensive ASW patrols in wartime
Will be hundreds or thousands of miles from the forward line of operations. It is not going to come across enemy ship or missile threats, short of a full sortie by a major enemy fleet.

Scenario 3: Operating in a combat zone. Not a job for a patrol boat anymore, but a full-on missile corvette or frigate.

Note that the above hasn’t really changed since WWII, where sub chasers, sloops, and corvettes did one job while destroyers and light cruisers did another. (With late war frigates & destroyer escorts kind of being a general purpose hybrid, similar to a Cold War FFG-7 or 1990s Meko / La Fayette general purpose frigate).

Cyclones did have ASMs equipped in the form of griffin ASMs, however as I’ve noted I think the cyclones and the FRCs (and their predecessors) are woefully undergunned

A properly armed PC or OPV could fill the same role as a WWII PT boat.

That's the job of a missile FAC these days.

Which means you need Harpoon or equivalent missiles (or Tomahawk Block 4 ASMs, which require an even heavier launcher), plus the combat sensors to give them targets.

And those sensors and combat systems are the expensive parts of a ship!

A corvette would fill the same role as well WWII corvettes and DEs.

So, you want an OPV with heavy ASW capabilities plus antiship missiles, and enough AA to make attacking one a questionable activity?

Such a thing would be on the order of 1000 tons minimum displacement, and probably closer to the size of a full on FFG7. Not cheap, either, due to all the fancy systems.

And honestly, it would definitely be something that would benefit from something like the LCS modules and/or STANFLEX. You'd need to have some extra combat modules laid out ahead of time, because the typical missions would not require the full combat capabilities. I'd leave the AAW capabilities in. It may be useful to be able to swap between gun modules, 57mm for the usual patrolling, 3" guided/rocket boosted for full combat.

 

[TomS]

Heavyweight torpedoes on a surface ship is kinda weird.

Nevertheless, it was a thing in that era. The Knox class even had a torpedo room aft for a pair of heavyweight tubes (either Mk37 or Mk48). A few ships even got the tubes but not the actual torpedoes. The space got taken over for IVDS or TACTASS early on.

A surface launcher for heavyweights is a lot easier than a sub tube, because it doesn't have to hold sea pressure, just a quick ejection pulse. No reason it couldn't be fiberglass, even. It's not like this is a great unknown -- heavyweight torpedoes were common on destroyers until the end of WW2, after all.

 

[Scott Kenny]

Heavyweight torpedoes on a surface ship is kinda weird.

Nevertheless, it was a thing in that era. The Knox class even had a torpedo room aft for a pair of heavyweight tubes (either Mk37 or Mk48). A few ships even got the tubes but not the actual torpedoes. The space got taken over for IVDS or TACTASS early on.

A surface launcher for heavyweights is a lot easier than a sub tube, because it doesn't have to hold sea pressure, just a quick ejection pulse. No reason it couldn't be fiberglass, even.

You're still talking about enough of an ejection pulse to accelerate a 3500lb object to 50 knots in its own length.

It's not like this is a great unknown -- heavyweight torpedoes were common on destroyers until the end of WW2, after all.

And heavyweight torpedoes on surface ships for ASuW were discarded basically as soon as guided missiles were a thing.