Monday, August 31, 2020

Torpedo Development

The US Navy’s torpedo, in its current form, has been around since at least the early 1900s.  In fact, aside from improved guidance, the basic torpedo is almost unchanged.  Over the ensuing 100+ years, huge strides have been made in all kinds of weapons but, for some reason, the torpedo has languished.  Yes, there have been improvements in engine efficiency and sensors/guidance but the fundamental torpedo has not changed.  That seems odd, doesn’t it?  As with so many vital combat systems (ASW, naval gun support, armor, etc.), the Navy has shown little interest in the torpedo and made little effort to develop it. 

Well, it’s a torpedo, you say.  What else can be done with it?  It is what it is.  If that seems like a reasonable summation to you then congratulations, you’re a prime candidate for admiral in the US Navy.  For the rest of us, let’s take a look at what developments might be possible for the torpedo.

The Navy’s current heavyweight torpedo is the Mk48.  Here’s a few features and points of interest:
  • Mk48 has been operational since 1972.
  • Mk48 Mod 5 ADCAP (Advanced Capability) IOC 1987
  • Mk48 Mod 7 CBASS (Common Broadband Advanced Sonar System) IOC 2006


Mk48 Torpedo Features
Size
19 ft long, 21 in diameter
Warhead
650 lb, high explosive
Cost
$3.8M for current version
Range
31 miles at 40 kts



So, what’s wrong with that?  It seems like a good torpedo, right?  Wrong!  Let’s see what other countries have in the way of torpedoes.

Russia leads the way in torpedo advances and development, dating back to the Cold War efforts of the Soviet Union.  The Soviet Union/Russia has always relied on their submarine fleet to compensate for their lack of surface navy capabilities compared to the West/US so it is not surprising that they lead the world in torpedo development.

Germany and China also have some noteworthy torpedoes.

The UK’s Spearfish torpedo, while fairly pedestrian, is reported by NavWeaps as having an 80kt max speed version which would be impressive for a conventionally powered (non-supercavitating) torpedo.(3)

The table below lists some of the features and examples of torpedo developments that the US lacks.


Foreign Torpedoes
Supercavitation
German firm in early 2000’s developed a 250 mph torpedo (1);  Russian VA-111 Shkval 230 mph (2);  SKorea has a supercavitating torpedo (see, “Korean Supercavitating Torpedo”)
High explosive weight
Russian 650 mm 65-76 with 992 lb warhead;  Russian 65-76 DST92 with 1225 lb warhead;
Very long range / very high speed
Russian 650 mm 65-76a with 62 mile max range and 50 kts max speed;  UK Spearfish with 80 kt max speed (3)
Wake homing
Russian 650 mm 65-76;  Chinese 533 mm Yu-6



The table demonstrates that existing technology is significantly beyond that of the US Mk48 torpedo.  Given our dependence on submarines to carry a lot of the naval combat responsibilities during war, this is disappointing.  As with mine countermeasures, ASW, naval gun support, ship armor, and so many other areas of naval combat, the Navy steadfastly refuses to recognize and support the development of key areas and torpedoes are yet another example.  Because torpedoes don’t garner giant sums of money in the budget, the Navy has little interest in torpedo development.  You would think the US Navy would have forever learned an institutional lesson about torpedoes from its WWII fiasco … but obviously not.

Clearly, the prize for the best torpedo in the world goes to the Russian 65-76 DST92, wake homing, 1225 lb warhead, 62 mile range, and up to 50 kt speed.  The US Navy Mk48 isn’t even in the running!

Before we move on from current, state of the art foreign torpedoes, let’s recall a torpedo from the past – the Japanese Type 93 Long Lance.  The Long Lance was a 24 inch diameter torpedo with a 1080 lb warhead and a range of 12 miles at 49 kts (22 miles at 36 kts).  This was a ship killer!  For more on WWII torpedoes, see “Torpedoes –Then and Now”.

Moving beyond the current state of the art – and the past! - , what future torpedo developments should we be looking at?  Here’s some possibilities:

Stealth – just as aircraft stealth took a giant leap forward with proper shaping and coatings, so too, might torpedoes benefit from shaping and coatings designed to reduce the acoustic signature and reflectivity of sonar sound waves;  torpedo noise reduction (propulsion, mainly) is certainly possible though possibly at the expense of speed

Supercavitation – the concept has already been demonstrated and just needs to be refined to allow more effective steering and target sensing

Multiple Warheads - a torpedo that can separate into multiple warheads like a MIRV or cluster bomb might prove useful in evading torpedo defenses and maximizing damage

Tagging – torpedoes that ‘tag’ a target rather then explode might prove useful in tracking ship movements and finding larger task forces;  magnetic or chemically attaching ‘warheads’ would seem possible

New Explosives – Significant advances have been made in air/land explosives and that leads one to speculate that similar advances ought to be possible for torpedoes;  for example, the equivalent to fuel-air explosives, using chemical-water reactions are theoretically possible given the existence of elements that react violently with water

Wake Homing – again, this technology exists and just needs to be adapted to US torpedoes and, possibly, enhanced

Chemical Trace Homing – small quantities of chemicals given off by the target ship are ‘sniffed’ in the water and tracked; this technology has been demonstrated in laboratories and rumor suggests is being tested in Russian submarines;  the challenge is to miniaturize it and adapt it to torpedoes

Terminal Evasive Maneuvers – enemy countries are working on active anti-torpedo interceptors so, just like anti-ship cruise missiles are capable of performing terminal evasive maneuvers, there is no reason why a torpedo shouldn’t be able to do the same

Littoral – the Navy found out that the neither the Mk48 nor the Mk54 lightweight torpedo were effective in shallow water ASW scenarios;  we need to develop a shallow water torpedo

Networking – cruise missiles are capable of networking, in flight, and performing self-designation of targets;  similarly, a torpedo salvo ought to be able to network and self-determine target allocation

Containerized Storage and Launching – just as VLS missiles are now containerized to reduce maintenance and protect the missiles from the environment, so too, should torpedoes be containerized for storage and launch



There you have some examples of the kinds of torpedo developments the Navy should be looking at.  I’m sure there are many other possibilities, as well.  If we’re going to depend on our submarines to carry the load in future naval combat then we simply must provide our subs with the very best torpedoes in the world.  At the moment, we are not doing that and, in fact, we are running a distant second to Russia.  The Navy’s failure to aggressively develop new torpedo capabilities hamstrings our submarine’s combat performance.  This has to change.  We cannot afford a repeat of the WWII torpedo fiasco.  We need to do the hard work and develop new torpedoes … now.



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34 comments:


  1. "As with so many vital combat systems (ASW, naval gun support, armor, etc.), the Navy has shown little interest in the torpedo and made little effort to develop it."

    But ASW, torpedos, NGFS, mine warfare, and armor are uncool. We've got lots of cool stuff like LCSs that go really fast; and Ford aircraft carriers that have computerized catapults, arresting gear, and weapons lifts; and Zumwalt destroyers with these really neat guns that nobody makes bullets for; and LHAs and LHDs that can haul around a lot of Marines and their equipment, but can't get the equipment ashore. They aren't demonstrated any appreciable combat effectiveness, but boy are they cool.

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  2. A simple advance would tweak ASROC to hit ships.
    https://en.wikipedia.org/wiki/RUR-5_ASROC

    Also, slow long-range harbor torpedoes.
    http://g2mil.com/harbor-torpedo.ht

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    1. "harbor torpedoes."

      That's exactly the kind of idea and development I'm talking about. Excellent!

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    2. Link got trimmed.
      http://g2mil.com/harbor-torpedo.htm

      Delete
    3. No problem. The link fooled me initially but it was obvious what it needed to be. Good article. I've enjoyed your writings. Keep it up!

      Let me know if you'd ever like to author a guest post!

      Delete
  3. Supercavitation torpedoes are generally short range weapons. Wiki lists the range of the Shkval 2 at 6.8 to 9.3 miles. And, something moving at 200+ mph in deep water will have a difficult time of maneuvering.

    Also, wouldn't a containerized torpedo take up more volume which would limit the number of torpedoes a submarine could carry?

    Your idea of a fuel-air equivalent explosive for a torpedo is interesting. I wonder if the increased pressure at depth would limit the spread of such an explosive. Then again, maybe that might work to its advantage. Though, there is the safety issue if such a warhead leaked inside a submarine.

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    1. Don't get caught up in the exact details of the proposed possible developments. Some would certainly work and some of them might well not prove to be practical. The point is that the Navy is not putting any effort into developing torpedoes, in general. We need to be researching and developing instead of ignoring torpedoes.

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    2. The most likely version would use a base charge to disperse finely powdered pure sodium into water, where the high pressure would actually probably increase the speed of the reaction by keeping plenty of water in contact with the sodium. This would produce a massive amount of hydrogen and heat which tends to produce a secondary explosion on contact with the oxygen in the air.

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    3. Just did a search for Sodium torpedo. The Chinese apparently have this type of warhead for their Yu-9 torpedo.

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    4. Water reaction warheads carry their own risk, sodium warheads sounds great....... when they hit the enemy. Spring a leak on one of them and they will make the Kursk look like sparkle.

      Also don't get too caught up on what the Chinese said, they might have tested the concept but insofar we don't have proof that they have actively used such a weapon.

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  4. I would also add depth to the list of advancements. Many torpedoes are limited to fairly shallow depth and many submarines can also only fire from fairly shallow depth. A submarine able to fire torpedoes up from the deep would be almost invulnerable to current weapons.

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    1. With 'swim out' torpedoes, I'm not certain that launch depth is an issue any more. I just don't know. Maybe someone can chime in?

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  5. Great post and ideas!! I admit im a bit shocked at the pricetag on our current arsenal though. Didnt realize they were as spendy as Tomahawks!!
    I like the outside the box thinking!! Hopefully torpedoes get some attention again, as long as the changes arent another transformational nightmare!!

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    1. I agree we need to push the art on the high end capabilities of the torpedoes. But we also need cheaper, good enough, torpedoes. Not all targets require something fancy. A large amount of very important ships are auxiliaries. All those needed and mostly defenseless supply and support ships. Good enough torpedoes allow you to save your expensive, low density munitions for higher end targets. The cheaper torpedoes are also better as the mainstay of your training shots.

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  6. Also we should be looking at improvements to torpedo Tubes. Currently they basically are the same as we used in WW2 except for data provisions (wire guidance and preprogramming links). One thing I've always thought would be useful would be VLT (Verticle Launched Torpedo) tubes, especially for surface attack. I really want to know what kind of performance you could get out of a torpedo the size of a Trident II.

    Randall Rapp

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  7. The RUM-139 VL-ASROC is an anti-submarine missile, currently built by Lockheed Martin for the U.S. Navy.This uses the Mk 54 light weight torpedo (Wikipedia) .
    So this torpedo system would not work in a littoral environment. Looks like the navy needs to fund research for surface ASW and get a effective system.


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  8. OT, but Kudos to these folks here, Skipper:
    https://www.washingtonexaminer.com/news/crew-survives-navy-surveillance-aircraft-crash-in-virginia

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  9. It has always interested me why the flare and the MIRV concept has never been reproduced anywhere apart from their respective branches.

    For surface ships, we could always fire up a cloud of metal or other suitable materials to misguide missiles or even serve to destroy them. For submarine, i would love to see a torpedo that launches multiple decoy other torpedoes to obfuscated enemy ships or even served as targets for anti-torpedoes systems.

    The MIRV concept to be truth has been reproduced by multiple systems like missiles and cluster bombs but there are other opportunities like the Russian cluster depth charges or cluster artillery shells that we somehow hadn't even looked at.

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  10. Water's density is much higher than air and sea water is electrically conductive, therefore, do not think missiles while develop torpedo. Effectively, there are fewer nations are actively developing torpedo than missiles.

    Because water density thus resistance is high, don't expect a torpedo can travel a very long distance except Russia's under developing nuclear powered torpedo carrying nuclear warhead.

    An interesting new technology from China's new Yu-10 (or Fish-10) torpedo is acoustic imaging. This torpedo can produce an image from acoustic wave than swim toward this ship (or submarine). It can even select location of the ship to hit. It was first shown in service in 2019.

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  11. ipnam, BAE Starstreak SAM, has 3x laser guided darts in one missile. A SSM version would be an interesting way to dilute terminal defenses.

    https://en.wikipedia.org/wiki/Starstreak

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    1. Thanks for the link! I have read into the system but it's quite limited in scope to what I am proposing. They are by all means only three smaller missiles and they have the disadvantages of having to actually hit the projectile. My proposal is for a cloud (of explosives might have more merit than metals) that is created by proximity fuses mini-missiles fired from presumably VLS system. It is in fact a step in the right direction and I would love to see the LMM system that Britain is developing. Do you know of any data regarding the Seastreak system? The limited amount of information available didn't strike me as a capable system.

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  12. "Multiple Warheads - a torpedo that can separate into multiple warheads like a MIRV or cluster bomb might prove useful in evading torpedo defenses and maximizing damage."

    A torpedo with multiple warheads would work provided each had their own propulsion system sufficient to reach the target. A cluster bomb dropped from an aircraft has the advantage of gravity doing most of the work, so it can be unpowered.

    At the same time, what is the advantage of 2 or 3 smaller warheads as opposed to one larger one? Even if all of the multiple warheads hit, there would be less energy delivered and it would not be as concentrated compared to one larger warhead.

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  13. The Navy should just by a torpedo from a country that has shallow water torpedo like Germany or Poland maybe Sweden, and focus the development on "blue" water combat.

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    1. What shallow water torpedo do you suggest?

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    2. Maybe the German DM2 A-4 or Swedish Torped 621. They should be designed for operations in the Baltic with shallow water.

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  14. A torpedo travels in water which is much more dense than air. Also, in sea water, radars don't work. Ships detect incoming torpedo by sonar. Making a torpedo stealthy usually means it is quiet. There is a conflict --- while a torpedo propels fast, it is noisy. MK48 torpedo usually give two ranges - high speed (noisy and shorter range) and low speed (less noisy and longer range).

    Recently, Russia has developed a torpedo interceptor, only one in the world. Usually, ships make noises to cheat a torpedo's sonar (only work for short range) or make sharp turn to escape an incoming torpedo.

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  15. There have been many groups in the Navy that have tried to improve the effectiveness of these weapons, unfortunately all their efforts have been repeatedly torpedoed by the Navy brass! :(

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  16. This is a great example of where incremental changes could(??) keep systems relevant. It seems that basically the Mk48 is out there packed with 90s tech(??). How much room could be created by shrinking the electronics/propulsion to modern standards? Maybe that extra space could accomodate additional explosive(??) Just a thought. Still wouldnt make it comparable to other countries weapons, but honestly 650lbs is surely a sub-killer, and still quite devastating to todays surface ships. 1200lbs sounds better of course, but is it necessary??

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    1. "but is it necessary??"

      Depends on the target. To sink an Iranian 3-man patrol boat, it's more than enough. To sink a modern, large tanker, it would require several, at least. To sink a Chinese aircraft carrier or Type 055, again, several.

      The Mk48, in the past, was not considered a sure kill against a Soviet double hulled, titanium submarine.

      So, it depends on the target but there are certainly reasonable and likely scenarios that cry out for much greater explosive effects than the Mk48 provides.

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  17. How much better off would we be if the billions wasted on the Zumwalts and LCSs would have been spent instead on torpedoes, ASW, and mine countermeasures?

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    1. Right?? We might have had a proper Tico replacement, the Spruances would just be phasing out, and the FltIII Burke could instead be a new ship with proper margins...!! Certainly most weapons could be modern and more capable!!
      Soooo many possibilities if only....

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    2. Alternately, how much better off would we be if we actually developed a surface launch Mk. 48 that could go on a small, fast and relatively expendable ship like the LCS with ASuW or ASW module in...

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  18. Are we spending way too much on platforms, and not enough on the weapons they carry? Sure seems that way.

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    Replies
    1. I agree. The Russians, in particular, seem to be doing the opposite.

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