Future Heavyweight Torpedo Development

FlameCxbra said:
The FY 2026 request for budget authorization for the mk48 states a supposed switch to the stored chemical energy propulsion for the mod 9.
View attachment 790980
https://www.highergov.com/budget/mk-48-adcap-f4adcde/

Now whether its going to be a similar SF6/Li Rankine engine as the mk50 (or L3Harris's mk54 mod 2), or some other exotic combo, its anyone's guess.
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Yep, this is the same info I linked to above.

I am pretty sure SCEPS refers specifically to the SF6/Li engine. That's the same thing being used in the CRAW (ultralight torpedo), also referred to as SCEPS.
 
Scott Kenny said:
Had to hang like a 5deg down bubble for a minute or two post torpedo shots when I was driving.
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The wire is cut at the TMD so I'd assume that was to ensure no more wire remains in the tube before the muzzle door is shut.

The TMD here has the interfacing umbilicals connected and stays behind:
tmd.jpg

(I don't even think it would clear the tube. It's locked in place and if it came loose and got jammed in there things would be ugly.)
 
Speaking of the umbilical, L3Harris are developing a fiber optic link for the MK 48 Mod 8 to replace the copper wire in existing Mk 48s.

https://www.l3harris.com/newsroom/e...delivering-real-time-torpedo-guidance-us-navy
The Improved Post-Launch Communications System (IPLCS) is a fiber-optic cable tether that connects the torpedo to its origin submarine, providing increased bandwidth for real-time data, a greater communications range along with better strength and reliability. The system is designed for the newest iteration of the MK-48 (Mod 8) torpedo, which will be the Navy’s next generation submarine-launched weapon system with upgrades beginning in 2029.
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Bruno Anthony said:
Is SCEPS quieter than the turbine that was passed on?
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What is SCEPS?

tychosis said:
The wire is cut at the TMD so I'd assume that was to ensure no more wire remains in the tube before the muzzle door is shut.
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I was under the impression that the wire was cut at both ends (TMD* first then at the Mk-48 end).

*What does TMD stand for?
 
NMaude said:
I was under the impression that the wire was cut at both ends (TMD* first then at the Mk-48 end).

*What does TMD stand for?
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Yeah, it's cut at both ends but obviously we're really only worried about the trailing end fouling anything.

TMD is the torpedo-mounted device, I'm sure it had a more formal name but was always referred to as the TMD.
 
whatismoo said:
Then what is RAPTOR?
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It a proposed "cheaper" torpedo less capable than an ADCAP. I guess I should have clarified that we don't really need a clean-sheet design to continue with torpedo improvement. The forebody and afterbody can be completely decoupled and worked separately without having to be too concerned with overall weapon design.

I haven't heard much about RAPTOR so I'm not sure how it's progressing. Honestly, sounds like someone's grift. We don't really have the magazine depth to be carrying around less-capable weapons.

(edit, thanks to @FlameCxbra -- TMD is actually "tail mounted dispenser!" Either the torpedomen lied to me or it's been too long, there was nothing but trouble down in that room anyway...)
 
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tychosis said:
It a proposed "cheaper" torpedo less capable than an ADCAP. I guess I should have clarified that we don't really need a clean-sheet design to continue with torpedo improvement. The forebody and afterbody can be completely decoupled and worked separately without having to be too concerned with overall weapon design.

I haven't heard much about RAPTOR so I'm not sure how it's progressing. Honestly, sounds like someone's grift. We don't really have the magazine depth to be carrying around less-capable weapons.
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I meant it rhetorically, but it (to be fair) is explicitly conceived around trading ASW performance for ASuW performance. Last I heard it was PMS404's baby? CAPT Polk has talked about it at a lot of conferences since 2024.
 
NMaude said:
What is SCEPS?



I was under the impression that the wire was cut at both ends (TMD* first then at the Mk-48 end).

*What does TMD stand for?
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SCEPS is the Stored Chemical Energy Propulsion System, which is a gas/liquid reacting with metal propulsion, in this case, Sulfur Hexaflouride is sprayed on Lithium, which creates heat. This heat is then used to heat a liquid and drive a Rankine cycle (Steam) engine.

The cool bit about the reaction is that supposedly the waste products of the SCEPS propulsion take up less space than the reactants, thus making it so that you don't have to throw the waste gas overboard.

The TMD is the Tail Mounted Dispenser for paying out guidance wire.
Here is a patent for one
 
Bruno Anthony said:
So we dumped the Mk50 just to restart it with a different name 20 yrs later. I’m sure that makes sense to someone somewhere.
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The Mk 54 front end was lifted from the Mk 50, so basically we're coming around to essentially a product-improved Mk 50 now.

The thing is, 25 years ago, we thought the pressing threat was the shallow-water, speed limited AIP or DE subs, not nuke boats. So, it kinda made sense to go for a cheaper weapon without the extreme deep diving performance of the Mk 50 in order to field a useful number.
 
Bruno Anthony said:
Perfectly ass backward
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Well, the point isn't to replace Mk.48 but supplement it at ~1/10th the cost because there are a lot of things to sink and not so many Mk.48s... I'm just reiterating what comments have been made by CAPT Polk publicly.

https://www.twz.com/sea/navy-wants-a-cheap-heavy-torpedo-that-can-be-stockpiled-fast
RAPTOR, as Polk describes it, might pinch-hit in the case of a parts squeeze.

“What RAPTOR is, talking about supply chain challenges,” Polk said, “is, what can I make that looks like a heavyweight torpedo, but with procurable parts.”

Rear Adm. Todd Weeks, program executive officer for strategic submarines, said the prospect of a future hot war in the Pacific also demands unconventional solutions.

“If we go to war today, it’s with the Navy we have,” he said. “So thinking out of the box, thinking about the problem differently, is really what this is all about. It’s as much a thought exercise today as it is anything else. But we’ll see where it goes.”
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Rear Adm. Weeks called RAPTOR the product of “a lot of smart people sitting around trying to rethink the problem.” He and Polk characterized the development effort as consisting to date of tabletop exercises and PowerPoint presentations and emphasized that no program of record yet existed for RAPTOR.
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Polk hinted that a limited-mission cheap torpedo might have applications to other platforms apart from Navy submarines, but declined to expand on the other uses being considered.

“There’s other platforms that could launch a heavyweight torpedo, if necessary,” he said. “Some things are in development right now. I guess we’re trying not to limit ourselves to just submarine launch applications.”

Ships, helicopters, and maritime patrol aircraft all launch torpedoes in today’s U.S. Navy. Unmanned systems will also deploy them in combat in the future.
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TomS said:
The Mk 54 front end was lifted from the Mk 50, so basically we're coming around to essentially a product-improved Mk 50 now.

The thing is, 25 years ago, we thought the pressing threat was the shallow-water, speed limited AIP or DE subs, not nuke boats. So, it kinda made sense to go for a cheaper weapon without the extreme deep diving performance of the Mk 50 in order to field a useful number.
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I wonder if any of the Mark 50s are still operational?

"Many components for the Mk 54 came from the older Mk 50, and production of that model halted in the mid-1990s. Since then, old Mk 50s have been cannibalized for parts but that supply is running out."

See:

https://www.strategypage.com/htmw/htsub/articles/20130913.aspx
 
dumpster4 said:
I wonder if any of the Mark 50s are still operational?

"Many components for the Mk 54 came from the older Mk 50, and production of that model halted in the mid-1990s. Since then, old Mk 50s have been cannibalized for parts but that supply is running out."

See:

https://www.strategypage.com/htmw/htsub/articles/20130913.aspx
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That’s a good question. Were they just pulled out of service and put on shelves? They kinda just disappeared.

No bigger question mark than post WW2 ASW torpedoes. Especially the Mid to late Cold War ones. Expensive as fukk and I’m not buying that anyone knows for sure how these would act in combat. And I don’t mean against a sampan.
 
Bruno Anthony said:
That’s a good question. Were they just pulled out of service and put on shelves? They kinda just disappeared.

No bigger question mark than post WW2 ASW torpedoes. Especially the Mid to late Cold War ones. Expensive as fukk and I’m not buying that anyone knows for sure how these would act in combat. And I don’t mean against a sampan.
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Mk48s get shot as EXTORPS something like 3x before they are rebuilt with a live warhead. So we do know that they'd work. Not just that the basic design works, that that specific torpedo works.
 
Scott Kenny said:
Mk48s get shot as EXTORPS something like 3x before they are rebuilt with a live warhead. So we do know that they'd work. Not just that the basic design works, that that specific torpedo works.
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Are they tested against a submerged target? Have they been detonated against a submerged target?

“Sinking a stationary surfaced bulk with a noise-emitting source to attract a torpedo (a typical SINKEX scenario) is fine. It exercises the explosive train and one not particularly important acoustic mode. But it is far from a realistic test. The target is not underway, not evading, not using countermeasures, and most particularly, not submerged. The exclusively ASW torpedo Mk 46 can’t be tested realistically against a surface target at all.“

https://archive.navalsubleague.org/1997/the-trouble-with-torpedoes
 
whatismoo said:
Well, the point isn't to replace Mk.48 but supplement it at ~1/10th the cost because there are a lot of things to sink and not so many Mk.48s... I'm just reiterating what comments have been made by CAPT Polk publicly.

https://www.twz.com/sea/navy-wants-a-cheap-heavy-torpedo-that-can-be-stockpiled-fast
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“There’s other platforms that could launch a heavyweight torpedo, if necessary,” he said. “Some things are in development right now. I guess we’re trying not to limit ourselves to just submarine launch applications.”
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The USN had a manned minisub for (suicide?) missions involving heavyweight torpedo attacks against surface ships. Though I suppose that mission would be performed by UUVs today:

http://www.hisutton.com/SDV Mk9.html
The SDV Mk.9 is unique among the US Navy SEALs submersibles because it could be armed with two heavyweight torpedoes. The type’s existence is well known within the Special Forces community (and among some observers), but very little specific information has reached the public.
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dumpster4 said:
The USN had a manned minisub for (suicide?) missions involving heavyweight torpedo attacks against surface ships.
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Why would you think suicide?

High risk, certainly, but it launches from quite a way out.

Now, I doubt they'd recover the SDV, because that's a time intensive evolution. But grabbing the crew and high tailing it seems feasible.
 
Bruno Anthony said:
The target is not underway, not evading, not using countermeasures, and most particularly, not submerged.
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There are WSAT evolutions that test all of these, up to and including weapon triggering (without the boomy bits obviously.)

One of the primary reasons we retrieve the weapon is not only for reuse, but for the purpose of collecting this data.

Bruno Anthony said:
I’m not buying that anyone knows for sure how these would act in combat.
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Well yeah, the general public doesn't. This is intentional.

I work in an adjacent field for the same company and I have to jump through hoops for any weapon information that might be important to our development. You'll find few technologies as well-protected as torpedo guidance and countermeasures.
 
Bruno Anthony said:
Are they tested against a submerged target? Have they been detonated against a submerged target?

“Sinking a stationary surfaced bulk with a noise-emitting source to attract a torpedo (a typical SINKEX scenario) is fine. It exercises the explosive train and one not particularly important acoustic mode. But it is far from a realistic test. The target is not underway, not evading, not using countermeasures, and most particularly, not submerged. The exclusively ASW torpedo Mk 46 can’t be tested realistically against a surface target at all.“

https://archive.navalsubleague.org/1997/the-trouble-with-torpedoes
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Yes, there have been submarine sinkexes. Fewer now that the huge back stock of WW2 diesels have been used up.
 
XRNWEO said:
The Brits carried out a Sinkex to test a warshot Stingray, against a former Porpoise class SSK, moored at depth. I'm not aware of any similar heavyweight trials, though Spearfish has featured in several surface ship sinkex's.
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Yeah, while “Trust me, everything’s been tested” sounds great, I’m from Missouri. I’ve found a link to a company that uses a 100’ ft long metal cylinder that they lower into water being used as a target. That’s about it aside from component testing in various ways.

Considering how we announce things as important as BMD test results, it’s interesting that any submerged torpedo tests would be considered more secret.
 
Bruno Anthony said:
Would that be a searchable list?
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I'm sure there's a list of SINKEXes somewhere online. It's just not something I have bothered to keep track of personally.

You could also look up the big joint exercises like RIMPAC, as those usually have a SINKEX as part of the fun. Not sure what the Atlantic or Indian Ocean equivalent is called, though.
 
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