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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(1)https://news.yahoo.com/germanys-supercavitating-torpedoes-super-weapon-150000497.html

(2)https://en.wikipedia.org/wiki/VA-111_Shkval

(3)http://www.navweaps.com/Weapons/WTBR_PostWWII.php