Modern submarine chaser

[Scott Kenny]

Kind of what I had in mind with my patrol corvette derived from the 1,500 ton / 87m Gowind OPV design (MN L’Adroit / ARA Bouchard class), which is about the same size as the Oaxaca class or Batch 2 Rivers.

[...]

1800 tonne patrol corvette
D: 1,800 tons
Dim: 88.5 x 14 x 3.3m (overall), 87 x 12.7m (waterline)
S: 26-27 kts on diesels (2x 6.5 or 7.4MW MTU 20V1163)
10 kts electric mode (2x 360 KWe)
R: 6,000 nm @ 15 kts
Crew: 55 pax / 30 days supply

Guns: 1x 40mm 57mm or 76mm main gun, 2x 30x113mm Bushmaster
SUW: 4x or 8x anti-ship missiles
AAW: 1x RAM launcher (21x SAMs)
ASW: Bow sonar + optional VDS & 2x triple torpedo tubes on flight deck
Modular stern bay for 1 or 2x 30ft RHIBs/USVs + 2x 20ft containers
Hangar for 1x helo or 2x UAVs

Oh, good you included a hangar space! That was going to be my main criticism. You don't want to keep aircraft on deck unless said deck is 80+ft above the waterline.

I'd personally want the 76mm, but I suspect that a US-service version would end up with the 57mm. Though I'd bet that many other countries would run the OTO 76mm instead.

 

[H_K]

Oh, good you included a hangar space! That was going to be my main criticism.

Yes here's the internal arrangement (taken from the original Gowind OPV, with only minor changes, indicated in red + the enlarged superstructure and raised foredeck with inverted bow).

The modular arrangement would allow for the following:
- Hangar (port): 1x ASW helo or 2x VTUAVs or 1x 20ft container
- Boat bay (starboard): 1x RHIB or 1x ASW USV or 1x 20ft container
- Stern ramps: 2x RHIBs or 1x RHIB + 1x towed sonar
- Stern bay: 2x 20ft containers

 

[TomS]

I think the breakthrough is going to do all the processing on the ship or on the P-8, or even on shore,

Wow, history sure does rhyme a lot. This is exactly what they did in LAMPS (minus the ashore part). SURTASS also pushed its processing ashore, mainly. Offboard processing is a given, and old-hat for buoys.

 

[_Del_]

Wow, history sure does rhyme a lot. This is exactly what they did in LAMPS (minus the ashore part). SURTASS also pushed its processing ashore, mainly. Offboard processing is a given, and old-hat for buoys.

The Navy has been pushing "netcetric warfare" and "killchains" before those became buzzwords.
LAMPS processes the data then shares it. SURTASS did some signal-processing, but data-processing and analysis was ashore. They did that to keep the ship smaller, and I think with the way bandwidth is growing, we'll see that repeated. Where all the analysis and processing can take place without dedicated tactical platforms like LAMPS. The tactical platform (UAV, helo, ship, USV, XLUUV, whatever) will just need to carry a sensor or deploy the sensors, and not dedicate SWAP-C to the processing. Particularly with the bouys.

 

[Scott Kenny]

The Navy has been pushing "netcetric warfare" and "killchains" before those became buzzwords.
LAMPS processes the data then shares it. SURTASS did some signal-processing, but data-processing and analysis was ashore. They did that to keep the ship smaller, and I think with the way bandwidth is growing, we'll see that repeated. Where all the analysis and processing can take place without dedicated tactical platforms like LAMPS. The tactical platform (UAV, helo, ship, USV, XLUUV, whatever) will just need to carry a sensor or deploy the sensors, and not dedicate SWAP-C to the processing. Particularly with the bouys.

But it's foolish to get rid of the ability to process on the helo. FFS, that's why the USN went from SH2s to SH60s, to gain the ability to process on the helo! Maybe the datalinks are down to the ship/processing center. Maybe the processing center is having an issue. LAMPS III/SH60 still has a Sonar tech in the helo, listening and seeing basic-processed data. So the helo is capable of localizing and engaging a sub completely independently, without a single bit being transmitted between the helo and ship or helo and shore.

 

[publiusr]

When I think of ASW, I think of slow aircraft...choppers dragging lashed together shopping cart contraptions.

If you had much larger satellites and some way to turn the oceans transparent- --might that allow missiles with supercav munitions to be fired from a distance?

A solid rocket to help break the air/water interface.

Otherwise, getting ahead of a fast submerged target would demand F-14 to jet out, slow down, then drop munitions at slower speeds--not possible with F-14 only existing in Iran.

Maybe sub-aquatic drones as listen-only with a laser link to ask for air support missile trucks.

 

[Scott Kenny]

When I think of ASW, I think of slow aircraft...choppers dragging lashed together shopping cart contraptions.

If you had much larger satellites and some way to turn the oceans transparent- --might that allow missiles with supercav munitions to be fired from a distance?

A solid rocket to help break the air/water interface.

Otherwise, getting ahead of a fast submerged target would demand F-14 to jet out, slow down, then drop munitions at slower speeds--not possible with F-14 only existing in Iran.

Maybe sub-aquatic drones as listen-only with a laser link to ask for air support missile trucks.

Remember that a "fast" submerged target is only 25-45 knots.

Helos are twice that speed. Fixed wing MPA like S-3s or P-8s are at least 4x that speed.

Also, submerged targets are only going that fast when they're deep, they'll be unlikely to break 15 knots at periscope depth and going that fast will leave one hell of a visible wake behind them. IIRC, the rule of thumb for speed at periscope depth was Sea State + 2 knots. So Sea State 3 means a 5 knot target, trying to see a container ship doing 30+ knots. Sea State 6 means 8 knots. And no submariner likes being on the roof in Sea State 6.

 

[publiusr]

I do worry about faster munitions

A couple of breakthroughs at phys.org today:

"Scientists develop coating for enhanced thermal imaging through hot windows" Rice University has tech that can see despite a 600 C temperature.

From China:

Prototype network achieves seamless, all light mobile communication across air land and sea." Even from moving targets.

Put those two together...yikes.

 

[_Del_]

But it's foolish to get rid of the ability to process on the helo. FFS, that's why the USN went from SH2s to SH60s, to gain the ability to process on the helo! Maybe the datalinks are down to the ship/processing center. Maybe the processing center is having an issue. LAMPS III/SH60 still has a Sonar tech in the helo, listening and seeing basic-processed data. So the helo is capable of localizing and engaging a sub completely independently, without a single bit being transmitted between the helo and ship or helo and shore.

For a SeaHawk, lugging an extra man-sized and weight station is not a huge deal. Providing SWAP-C in smaller platforms is more difficult. It's also going to depend on the amount of data your sensor or array is generating. Which is why SURTASS signal data was sent ashore as TomS noted.

 

[Scott Kenny]

For a SeaHawk, lugging an extra man-sized and weight station is not a huge deal. Providing SWAP-C in smaller platforms is more difficult. It's also going to depend on the amount of data your sensor or array is generating. Which is why SURTASS signal data was sent ashore as TomS noted.

Right. And I expect the Navy's FVL choice to be a T901 Super Seahawk, with the cargo lifting capabilities of the Sierra while carrying all the ASW equipment of the Romeo.

Obviously a drone helo isn't going to carry much processing power, but it could reasonably carry some. Plus processing power is cheap enough that even disposable sonobuoys could pre-process some data.

The problem is that drone helos are currently small enough that they either carry a rack of sonobuoys or a lightweight torpedo, ~600lbs carrying capacity. I'd like the ASW drone helos to be able to carry both sonobuoys and an LWT, which means a carrying capacity of 1200-2000lbs. Plus the FLIR ball and a radar as standard equipment. Which probably makes for a load that not even an MQ8C can lift... I'd really like a minimal-weight airframe on MQ8C-ish dynamic components, like how the early MQ8s were to the Robinson R33s or 44s.

 

[H_K]

I'd like the ASW drone helos to be able to carry both sonobuoys and an LWT, which means a carrying capacity of 1200-2000lbs. Plus the FLIR ball and a radar as standard equipment. Which probably makes for a load that not even an MQ8C can lift

Rather than a single large & expensive helo doing detection, it might be cheaper & more effective to use multistatic sonar pinging from multiple platforms. That's why I proposed a VDS towed sonar and space for an ASW USV on my 1,800 ton patrol corvette concept. Add a small VTUAV (like VSR700) with a few sonobuoys + radar for periscope detection and that should give you pretty good area coverage.

I'm less worried about sinking the sub - once you've detected a sub and forced it to take defensive measures, the job is already 90% done. In wartime you can call in a land based patrol asset (fixed wing or helicopter) to drop a torpedo, but that's not relevant to most sub "engagements" which happen in peacetime. If the sub doesn't bug out you also have ship based torps or maybe another VTUAV on standby with a lightweight torpedo.

 

[Scott Kenny]

Rather than a single large & expensive helo doing detection, it might be cheaper & more effective to use multistatic sonar pinging from multiple platforms. That's why I proposed a VDS towed sonar and space for an ASW USV on my 1,800 ton patrol corvette concept. Add a small VTUAV (like VSR700) with a few sonobuoys + radar for periscope detection and that should give you pretty good area coverage.

You're still talking about a good 800lbs of gear between the sonobuoys and periscope radar.

Makes a big drone.

But honestly, for 90+% of the noncombat work of a subchaser, you want a real helo not a drone.

I'm less worried about sinking the sub - once you've detected a sub and forced it to take defensive measures, the job is already 90% done. In wartime you can call in a land based patrol asset (fixed wing or helicopter) to drop a torpedo, but that's not relevant to most sub "engagements" which happen in peacetime. If the sub doesn't bug out you also have ship based torps or maybe another VTUAV on standby with a lightweight torpedo.

Fair, though if you only have the VDS, USV, and one UAV pinging away, your other UAV must be working for you to have a threat to it.

Any chance you can enlarge the hangar enough to fit a Seahawk and a UAV?

 

[Foo Fighter]

I can see the helicopter doing more than chasing subs, can the drone do everything else the helicopter can do like moving injured crew and stores etc?

In time, certainly.

 

[publiusr]

Spacecraft can have tranches..drones too.

Have 24/7 weather drones talk to ASW weapon only drones via lasercomm

 

[Scott Kenny]

I can see the helicopter doing more than chasing subs, can the drone do everything else the helicopter can do like moving injured crew and stores etc?

In time, certainly.

Not anytime within the next decade or so. Maybe the next 2 decades...


I will note that I still want both a full helo and a drone, instead of helo or 2 drones.

 

[Foo Fighter]

Something of a fad perhaps but, talk about distributed sensors got me thinking that drones could do the sensing and the helicopter could launch weapons.

Keep the most valuable asset from radiating and you perhaps reduce the threat to that aspect of a distributed team for the job of sub hunting.

 

[Byeman]

Spacecraft can have tranches..drones too.

Have 24/7 weather drones talk to ASW weapon only drones via lasercomm

that is the issue, lasercomm is not all weather