RUR-5 ASROC and RUM-139 VL-ASROC (VLA)

[NMaude]

A few days ago I stumbled across this ASROC training video from Periscope Films and I was surprised when I checked the board that no specific thread for the ASROC has been posted so hear goes:

Now for some stats from the RUR-5 ASROC wikipedia page:

The RUR-5 ASROC (for "Anti-Submarine Rocket") is an all-weather, all sea-conditions anti-submarine missile system. Developed by the United States Navy in the 1950s, it was deployed in the 1960s, updated in the 1990s, and eventually installed on over 200 USN surface ships, specifically cruisers, destroyers, and frigates. The ASROC has been deployed on scores of warships of many other navies, including Canada, Germany, Italy, Japan, the Republic of China, Greece, Pakistan and others.[4]

Specifications
Mass	1,073 pounds (487 kg)[2]
Length	14.75 ft (4.50 m)[2]
Diameter	16.6 inches (420 mm)
Wingspan	26+7⁄8 inches (680 mm)
Warhead	Mark 46 torpedo, 96.8 pounds (43.9 kg)[2] of PBXN-103 high explosive; 10 kt (42 TJ) W44 nuclear warhead (retired)
Detonation mechanism	Payload specific

Detonation of W44 warhead launched by an ASROC in the 1962 Dominic Swordfish shot.

A dummy ASROC

The ASROC carried several different payloads - W44 equipped nuclear depth-charge, Mk-44 12.75" electric-torpedo or Mk-46 12.75" OTTO II mono fuel fuelled torpedo.

This weapon was further developed into the RUM-139 VL-ASROC missile.

Edited to add information from the RUM-139 wikipedia page.

The RUM-139 Vertical Launch Anti-Submarine Rocket (VL-ASROC or VLA) is an anti-submarine missile in the ASROC family, currently built by Lockheed Martin for the U.S. Navy.[1]

RUM-139 midflight
Type	Anti-submarine missile
Place of origin	United States
In service	1993 – present
Used by	United States Navy, Japan Maritime Self-Defense Force and others
Designer	Goodyear Aerospace
Designed	1983 – 1993
Manufacturer	Lockheed Martin
Produced	1993 – present
Mass	1,409 lb (639 kg)
Length	16 ft 1 in (4.89 m)
Diameter	1 ft 2 in (358 mm)
Wingspan	2 ft 3.4 in (696 mm)
Warhead	RUM-139A: Mark 46 Mod 5 torpedo RUM-139B: Mark 46 Mod 5A(SW) torpedo RUM-139C: Mark 54 torpedo[1]
Engine	Two-stage solid-fuel rocket
Operational range	12 nmi (22 km)[2]
Maximum speed	Mach 1 (309 m/s; 1013 ft/s)
Guidance system	Inertial guidance and Mk 210 Mod 0 Digital Autopilot Control subsystem
Launch platform	Mk 41 VLS
References	Janes[3]

 

[NMaude]

Here's a 1962 film about the live test of an ASROC with a nuclear depth-charge (W44 warhead) during the US's last atmospheric test-series, Operation Dominic I:

US Navy documented film from the 1962 Operation Swordfish ASROC Nuclear depth charge tests in the Pacific. Firing vehicle USS Agerholm DD826, USS Richard B Anderson DD786, and USS Bausell DD845 are shown during the test. Effects of the test and results on submarine Razorback 2.5 miles away are discussed. This is the only known test of the ASROC Nuclear Depth bomb. This video brought to you by the Friends of the USS Joseph P. Kennedy Jr DD850 .

 

[Scott Kenny]

As a submariner, nuclear ASROC et sim are the scary weapons to face. No noise of a helicopter thundering overhead. No tonals from MPA. Just a splash overhead followed by a very large boom. A boom large enough that you can't outrun it.

Conventional ASROC et sim are not as bad because you can hear the torpedo start up after the splash overhead and may even be able to outrun it (more technically, exhaust it).

 

[NMaude]

As a submariner, nuclear ASROC et sim are the scary weapons to face.

I imagine that the blast radius for even a small nuclear warhead would be fairly big.

On another note since you were in the submarine service were you ever involved with the SUBROC?

 

[Scott Kenny]

I imagine that the blast radius for even a small nuclear warhead would be fairly big.

On another note since you were in the submarine service were you ever involved with the SUBROC?

No, SUBROCs were retired by the time I was in. IIRC they got retired in the early 1990s.

 

[NMaude]

No, SUBROCs were retired by the time I was in. IIRC they got retired in the early 1990s.

Did you meet any submariners who'd been around when SUBROC was operational? did they have any interesting anecdotes about it? According to Chuck Hansen's article on its' W55 warhead in his "Swords of Armageddon" CD-ROM, the SUBROC was a "Hot" weapon.

 

[Cordy]

At SNA Jan 2019 the FFG(X) capabilities briefing slide under ASW mentions a future Mk41 VLA for all wx stand off ASW weapon, presuming replacement of the 1960's ASROC, nothing appears to have come of it.

 

[Ronny]

As a submariner, nuclear ASROC et sim are the scary weapons to face. No noise of a helicopter thundering overhead. No tonals from MPA. Just a splash overhead followed by a very large boom. A boom large enough that you can't outrun it.

Conventional ASROC et sim are not as bad because you can hear the torpedo start up after the splash overhead and may even be able to outrun it (more technically, exhaust it).

I vaguely remember reading somewhere about the effective radius of nuclear depth charge, it is surprisingly short against modern submarine due to their hull designed to sustain high pressure. I can’t recall the exact number now but I remember it something less than 1 km

 

[TomS]

At SNA Jan 2019 the FFG(X) capabilities briefing slide under ASW mentions a future Mk41 VLA for all wx stand off ASW weapon, presuming replacement of the 1960's ASROC, nothing appears to have come of it.

Vertical Launch ASROC (VLA) has been fielded since the early 1990s (since 2004 with the Mk 54 torpedo). It certainly fits the bill for an all-weather (wx) ASW standoff weapon. We haven't heard about it being added to FFG(X) but I'll be surprised if they don't slip it in quite early. Deferring it initially was probably just a budget issue.

 

[NMaude]

I've edited the thread's title so it also includes the RUM-139 ASROC-VL.

Does anyone know anything about the RUM-139's launch-booster, the Mk-114? The only thing I've been able to find out is its diameter (14.1"), burn time (5s) and thrust (11,000Lb).

 

[Moose]

At SNA Jan 2019 the FFG(X) capabilities briefing slide under ASW mentions a future Mk41 VLA for all wx stand off ASW weapon, presuming replacement of the 1960's ASROC, nothing appears to have come of it.

Extended-range VL ASROC is an unfunded priority. Has been for a bit now.

 

[NMaude]

Extended-range VL ASROC is an unfunded priority. Has been for a bit now.

Would the VL ASROC ER use a modified Mk-114 booster or would use, say, a Mk-72 booster?

 

[Moose]

Would the VL ASROC ER use a modified Mk-114 booster or would use, say, a Mk-72 booster?

Navy (and Army now) wouldn't be keen on the production line going to ASROC rather than Standard, and the cost change would be...noticable. The VLA-ER concept as usually described adds a wing kit to a mostly stock RUM-139, adds range without a ton of cost.

 

[TomS]

Navy (and Army now) wouldn't be keen on the production line going to ASROC rather than Standard, and the cost change would be...noticable. The VLA-ER concept as usually described adds a wing kit to a mostly stock RUM-139, adds range without a ton of cost.

Basically converging VLA and HAAWC. Sensible idea. Never happen.

 

[Scott Kenny]

Basically converging VLA and HAAWC. Sensible idea. Never happen.

Hey, sometimes you can get away with strangling the Good Idea Fairy and actually get a simple system that does the job NOW into service.

Don't laugh, it's happened a few times!

 

[Scott Kenny]

Did you meet any submariners who'd been around when SUBROC was operational? did they have any interesting anecdotes about it? According to Chuck Hansen's article on its' W55 warhead in his "Swords of Armageddon" CD-ROM, the SUBROC was a "Hot" weapon.

There were a few, mostly senior E6s and above, the only other SUBROC story I remember was talking about how there was a "hot run" procedure for them.

A "Hot run" is when the torpedo engine starts inside the tube without the stop-bolt releasing the weapon.

"But Scott," you say, "isn't SUBROC, well, a rocket?"

Yes, it is. The exhaust was calculated to blowtorch a hole through the ship in about 2.2 seconds. Through the breech door, through anything between the torpedo tube and any walls between the torpedo room and the engineroom watertight bulkhead, through the reactor, through the reactor compartment, and out the far side of the engineroom. (USN torpedoes are not exactly in the bow, they're set back behind the sonar dome in all boats since Thresher, and at a ~10deg angle outboard to the centerline to clear the sonar dome.)

You'd barely even finish saying "EMERGENCY REPORT, EMERGENCY REPORT, HOT RUN IN THE TORPEDO ROOM!" before the ship was holed through.

But Bureau of Ordnance says there must be a procedure in case you have a hot run, so there is.

More of a lesson in the bureaucrazy of the USN than anything else.

 

[zjz]

Reminds me of Sea Lance .....

UUM-125 Sea Lance - Wikipedia

en.wikipedia.org

 

[zjz]

https://www.usni.org/magazines/proceedings/2020/august/tactical-nuclear-weapons-sea

 

[zjz]

Would the VL ASROC ER use a modified Mk-114 booster or would use, say, a Mk-72 booster?

Lockheed Martin RUM-139 VL-Asroc

 

[NMaude]

Lockheed Martin RUM-139 VL-Asroc

I was talking about a possible ER version of the VL ASROC not the current one in production.

On another note does anyone know anything else about the RUM-139's guidance system (Inertial guidance and Mk 210 Mod 0 Digital Autopilot Control subsystem) aside from what's already mentioned in the wikipedia article?

 

[zjz]

https://apps.dtic.mil/sti/tr/pdf/AD1066772.pdf

 

[NMaude]

https://apps.dtic.mil/sti/tr/pdf/AD1066772.pdf

Thanks, however you should have the name of the report for the URL along with a brief description about what the document is:

ASROC ROCKET MOTOR MARK 37 MOD 0 OVERVIEW

From the report:

This report provides a description of the ASROC rocket motor Mark 37 Mod 0 and a general overview of its surveillance general history, safety and disposal options.

Edit: Do you have any links to such similar reports on the RUM-139 VL ASROC's Mk-114 launch booster, please?

 

[TomS]

The designation systems article notes that the TVC and digital autopilot allows VLA to fly a depressed trajectory to limit the impact of high-altitude winds.

 

[zjz]

Look for this conference paper :

VLA Missile Development and High Angle of Attack Behavior​

https://www.researchgate.net/publication/304253096_VLA_Missile_Development_and_High_Angle_of_Attack_Behavior

I could not find any soft copy, and I have only seen it in hard copy, talks about development of the VL and TVC for ASROC .....

 

[NMaude]

The designation systems article notes that the TVC and digital autopilot allows VLA to fly a depressed trajectory to limit the impact of high-altitude winds.

That makes sense also having a depressed trajectory should decrease flight time too.

VLA Missile Development and High Angle of Attack Behavior​

https://www.researchgate.net/public...Development_and_High_Angle_of_Attack_Behavior

Doesn't seem to have a readily downloadable file but the title is promising.

 

[Cordy]

India has successfully tested its Supersonic Missile-Assisted Release of Torpedo (SMART) with its LWT payload, the test objectives included missile flight up to the range and altitude, separation of the nose cone, release of torpedo and deployment of Velocity Reduction Mechanism, VRM, said to be met perfectly. China has developed Yu-8 anti-submarine missile which works on the same hybrid principle of SMART weapons system but has a range of only 40 km whereas SMART ~ 350 nm.

Targeting would be a problem at these ranges, speculating Indians have installed an eqivalent of SOSUS, but as a passive sonar system do wonder how effective in an era of very quiet subs.

 

[NMaude]

India has successfully tested its Supersonic Missile-Assisted Release of Torpedo (SMART) with its LWT payload, the test objectives included missile flight up to the range and altitude, separation of the nose cone, release of torpedo and deployment of Velocity Reduction Mechanism, VRM, said to be met perfectly.

Don't the Japanese have something similar?

 

[TomS]

Don't the Japanese have something similar?

Just an improved equivalent to VLA:

Type 07 vertical-launch anti-submarine rocket - Wikipedia

en.m.wikipedia.org

 

[NMaude]

Just an improved equivalent to VLA:

Type 07 vertical-launch anti-submarine rocket - Wikipedia

en.m.wikipedia.org

That makes sense.

 

[Scott Kenny]

India has successfully tested its Supersonic Missile-Assisted Release of Torpedo (SMART) with its LWT payload, the test objectives included missile flight up to the range and altitude, separation of the nose cone, release of torpedo and deployment of Velocity Reduction Mechanism, VRM, said to be met perfectly. China has developed Yu-8 anti-submarine missile which works on the same hybrid principle of SMART weapons system but has a range of only 40 km whereas SMART ~ 350 nm.

Targeting would be a problem at these ranges, speculating Indians have installed an eqivalent of SOSUS, but as a passive sonar system do wonder how effective in an era of very quiet subs.

Given how far away the USN SOSUS system is admitted as tracking things, I'm not sure it's an issue.

 

[NMaude]

Here's interesting document I stumbled across yesterday concerning the gear for handling the RUR-5:

Guide for Anti-Submarine Rocket (ASROC) Missile Gauge and Handling Equipment Certification Procedure

And a PDF copy:

 

[zjz]

That makes sense also having a depressed trajectory should decrease flight time too.



Doesn't seem to have a readily downloadable file but the title is promising.

The book is found here :

NEAR, Inc.: Book For Sale

Nielsen Engineering & Research (NEAR) provides aerodynamics analysis and design expertise through consulting services and software licenses. Geographic information systems and geographic data mining services and software are available. NEAR's speci

www.nearinc.com

Found it on Scribd, but I will not post link here, as I am unsure if there is violation of copyrights issue .....

 

[NMaude]

Found it on Scribd, but I will not post link here is I am unsure about how this site may frown on copyrights issue .....

If you would PM me the scribe link, please, it would be appreciated.

 

[zjz]

The trick is to Google using the Conference name, not the paper title

 

[sferrin]

Don't the Japanese have something similar?

Maybe you're thinking of South Korea? (Red Shark)

 

[zjz]

Would be interesting to compare the US, Japanese and S.Korean versions of ther VL-ASROC.

 

[TomS]

Maybe you're thinking of South Korea? (Red Shark)

Red Shark is very much in the same class as VLA and the Type 07 -- range somewhere between 20 and 40 km, depending on source. The Chinese Yu-8 also seems to be in the same ballpark, maybe 50 km but still nowhere close to the range of the Indian SMART. All of these missiles, aside from SMART, can be targeted from onboard sensors, at least in theory (50 km is pushing it, especially since Yu-8 has a much shorter ranged payload than the Western designs.)

I sincerely cannot figure out the use case for SMART, but I'm sure it makes sense to the Indians.

 

[Scott Kenny]

I sincerely cannot figure out the use case for SMART, but I'm sure it makes sense to the Indians.

I suspect that the Indians have a SOSUS-equivalent in the Indian Ocean and are planning on using it for targeting.

 

[NMaude]

I suspect that the Indians have a SOSUS-equivalent in the Indian Ocean and are planning on using it for targeting.

I suppose the targets the Indian navy has in mind are PLA:N SSNs and SSBNs.

 

[Scott Kenny]

I suppose the targets the Indian navy has in mind are PLA:N SSNs and SSBNs.

Primarily. Though I'm sure ruining the day of the Pakistani Navy is also on their to-do list.