Extra long range torpedoes

The technology-dominated area of naval combat has spawned a couple operational research-centric publications, amongst them Wayne P. Hughes' "Fleet tactics" books. There aren't really the rivalling fleets to make much use of such theory any more, though.

One thing to ponder about is in my opinion the extra long range torpedo. It was published last year that an extended range (export) version of the newest German modular heavyweight torpedo has set a range record of 140 km*.
This was certainly done with a low cruise speed** and even greater ranges would be possible with lower cruise speeds. The role of natural currents was apparently not published.

photo: Atlas Elektronik
Still, such a long range is interesting. It's interesting because self-deploying naval mines could apparently be developed to match this performance, and this basically means you could infest almost all notable sea gates (straits) with mines without the need for a naval or aerial delivery platform.

Second, there's the question of ambush tactics with actual homing torpedoes in such sea gates. You could tell your ammunition to self-deploy, and then let it attack the approaching targets as a wolfpack.
The obvious challenge would be the means of communication, since such munitions (torpedoes) will rather not keep a cable (copper wire or glass fibre) intact over such a long distance and they are also unlikely to have  LF radio receiver as do submarines. The munition would need a different, suitable message receiver and decryption.
The end result could resemble the (not very successful) ambush lines of submarines as used during WWI (North Sea) and WW2 (Pacific).

Third, torpedoes can be deployed easily. A container ship with torpedo launchers in outwardly innocuous long ISO containers could deploy hundreds of torpedoes or self-deploying mines during a night and it wouldn't even look conspicuously on a radar screen. There is very little defence against such a platform in the opening stages of a naval war, or when foreigners insist on business as usual in a naval war zone (as in the Persian Gulf during the 1980's). This may indicate that coping with the munition rather than with the launch platform may be the better approach (as is happening in tank defence, air defence, C-RAM and has happened in regard to naval missile defence for quite some time).

Munitions getting more and more capable up to a point where theory needs to adapt and invent some new approaches is rare, but it happens. It happened with the invention of the torpedo, it happened when artillery shell fuses became smart (proximity fuses), when cruise missiles appeared, when cruise missiles became accurate, when air/ground missiles became accurate et cetera. The more sophisticated the munition becomes, the more tactical variations become practical and the more focus has to be on defeating the munition. The defeat of the platform becomes almost secondary, if not irrelevant after launch (as with coastal defence missile launchers).
Luckily, there are historical and technical analogies which help navigate the uncharted waters of military theory.


*: ~75 nautical miles. It's strange to see "km" in such a context
**: Maybe at a no-cavitation speed at which the torpedo would be quite silent, too.


  1. "The obvious challenge would be the means of communication, since such munitions (torpedoes) will rather not keep a cable (copper wire or glass fibre) intact over such a long distance and they are also unlikely to have LF radio receiver as do submarines. The munition would need a different, suitable message receiver and decryption."
    The communication is the difficult part. You could sink containers to the bottom of the sea and link them with fibre optics to a command center. But I have no idea how to conduct a suitable underwater communication of fast moving small objects over long distances. Long wavelengths get absorbed after a short distance under water and suitable short wavelengths would be X-ray. The communication is best conducted over shortest distance under water, requiring air or space assets for coordination. Is this still a torpedo or a robotic kamikaze submarine?

    1. VLF radio with a bandwidth of about 300 bit/s can be used to transmit to the torpedo if it's not too deep, but the torpedo couldn't transmit VLF radio itself.

  2. What about a staged torpedo , like a multistage rocket .
    You could have a very long range torpedo that is made up of 2 , 3 or 4 stages that are dropped as it travels , each stage could have its own com link with a small antenna floating on the surface like a Sonobuoy , and under the surface the comlink is still connected to the next stage of the torpedo through a cable .
    The torpedo travels to a target area at a cruise speed ,When the torpedo gets to the target area it separates the attack stage at the front from the last stage , maybe 15 - 20 km out , this way the attack torpedo would still be under control through the cable connected to the dropped comlink in the last stage , it would also allow the attack torpedo to be lighter , faster and more maneuverable than a standard long range heavy torpedo .
    The advantages could be that each cable in each section would not be too long so the risk of breaking the cable would be less . each stage that is dropped would also drop the empty fuel tank ( if its has a liquid fuel like hydrogen fuel sell ) or empty heavy batteries so torpedo doesn't have to carry a lot of dead weight . therefore its cruise speed could be alot higher .
    it wound travel at a deeper depth than a torpedo that needs to be near the surface to radio link , and it would have a real 2 way communication

    1. Rockets fight gravity, while torpedoes have about the same density as water.

      A shorter Torpedo would experience a greater hydrodynamic drag, so there is no real benefit to a multi-stage torpedo.

      One could think of a torpedo-like unmanned vehicle laying mines on autopilot, though.

    2. does not asroc, end the debate, over torpedoes?

    3. http://defense-and-freedom.blogspot.de/2009/06/sub-vs-asw-ship-range-mystery.html