Monday, March 17, 2014

SW/ASW Lessons

Submarines have historically had a huge impact on naval and merchant shipping and operations that goes beyond just tonnage sunk.  Naval operations, in particular, have been greatly affected by the mere threat of submarines despite a relatively lesser impact, in terms of tonnage of naval vessels sunk.  Historically, the submarine threat to naval vessels has been serious but manageable.

Today, though, modern submarines with long range, devastatingly powerful, high speed torpedoes have been accorded an almost invincible reputation by many.  On the other hand, some, a minority, to be sure, argue that modern anti-submarine platforms and weapons will make short work of submarines who can’t cope with fleets of helos and fixed wing sub hunters in addition to ships packed with sonar, towed arrays, signal processing computing power, and smart anti-submarine torpedoes  all backed by myriad types of airborne and satellite surveillance plus SOSUS type sensor deployments.

What is the reality of modern submarine warfare (SW) and anti-submarine warfare (ASW)?  Where does the truth lie?  Well, the SW and ASW fields are probably the least open in terms of authoritative public statements of capability.  Thus, anyone who hasn’t served in SW/ASW probably has little basis for any credible claims regarding SW/ASW performance.  Those who have served and have some knowledge rarely discuss it publicly and then only in general terms.

Having just stated that very few people have the background and credibility to authoritatively discuss SW/ASW, ComNavOps is now going to do just that?!  Actually …   No. 

Instead, we’re going to examine the history of modern SW/ASW for actual lessons and see what we can learn.  Unfortunately, few documented instances of modern SW/ASW exist.  Still, we’ll work with what’s available.

Probably the best example is the Falklands War.  As described in Harper’s report (1), the following submarines took part in operations for their respective sides.

British SW forces consisted of,

(2) Swiftsure class nuclear submarines (Spartan, Splendid)
(3) Valiant class nuclear submarine (Conqueror, Valiant, Courageous)
(1) Oberron class diesel submarine (Onyx)

British ASW forces included 12 ships, 6 submarines, and over two dozen helos.

Argentine SW consisted of,

(1) Type 209 class diesel submarine (San Luis)

Argentine ASW did not really exist in any meaningful way.

Let’s look at specifics of SW operations.  The San Luis claimed to have conducted three torpedo attacks. 

1 May – Attacked medium sized warships using sonar identification and targeting only. The ships were the H.M.S. Brilliant and the H.M.S. Yarmouth. The attack failed and the sub was, in turn, attacked for 20 hours with depth charges and at least one torpedo.

8 May – Attacked a submarine. The attack failed although an explosion was heard.  Presumably, the torpedo exploded against the seabed.

10 May – Attack on two destroyers, the H.M.S. Arrow and H.M.S. Alacrty. One torpedo was launched.  The attack was unsuccessful, however, an explosion was heard on the correct bearing 6 minutes after firing the torpedo.  Arrow later found her towed countermeasure was damaged which was taken as evidence that the San Luis’ torpedo had been successfully decoyed.  The second ship was not attacked because it had moved out of range in the intervening time.

British submarines, in turn, sank a WWII era cruiser.

The conclusions are fairly obvious. 

(1) Submarine SW operations were remarkably ineffective. 

The San Luis attempted three attacks, largely unhindered by ASW efforts, and achieved zero success.  The British sank the Argentine cruiser but achieved nothing further despite having six subs in theatre.  To be objective, the cruiser appeared to have no meaningful ASW assets protecting it and was more of a live fire exercise than an example of modern SW.  Also, to be fair, the British rules of engagement probably limited their submarines from accomplishing more.  The ROE’s were intended to prevent friendly fire incidents but that simply points up the difficulty in target identification during SW.

(2) ASW operations were remarkably ineffective and achieved what limited success they had only in passive ways. 

It is doubtful that the British ever held contact on the San Luis despite a multitude of ASW assets actively searching and the submarine approaching to within torpedo range on three occasions.  The only ASW success the British achieved was with passive torpedo decoys and even then the success was only realized in a delayed fashion when the decoys were recovered and found to be damaged.  In short, an entire fleet of ASW assets was unable to locate a single submarine despite the sub conducting three attacks and thus being in near proximity.

(3) Submarines exerted an influence far beyond their actual impact. 

The Argentines completely ceded the surface naval contest due to the mere threat of submarines after the sinking of the cruiser.  The British expended an enormous amount of effort attempting to counter the submarine threat and their movements and operations were greatly influenced by the ongoing submarine threat.

Let’s move on to the example of the Chinese submarine that surfaced in an American carrier group.  As the story is reported, a Song class diesel-electric submarine surfaced inside the USS Kitty Hawk group within 5 miles of the carrier on Oct 26, 2006.  US escorting forces and aviation assets failed to detect it until it surfaced.  To be fair, the carrier was undoubtedly not conducting wartime levels of ASW.  Still, operating near China, the carrier group should have been maintaining a vigilant level of awareness and yet failed to detect the sub – a sub that is of an inherently quiet type but not generally thought to be world class.

These are the only relevant real world SW/ASW examples that I’m aware of.  Not much of a database to draw lessons from, admittedly.  That said, modern SW may be less effective than is generally assumed.  Friendly fire concerns will be a major concern and impediment to SW.  Conversely, modern ASW appears to be only marginally effective, at best.

Please note that this post is not an opinion piece.  It’s simply an observation of the very limited real world operational experience that has been made public.  Whether the conclusions would hold across other navies, platforms, and scenarios is highly debatable.  At the very least, though, the data needs to be considered and factored in to SW/ASW discussions.  To blindly claim that modern submarines are invincible or, conversely, that modern ASW is lethally effective is to ignore the available evidence.  The wise student of SW/ASW would do well to exercise a healthy degree of self-doubt about their position, whatever that might be.

(1) Naval War College, Submarine Operations During the Falklands War, LCdr. Steven R. Harper, USN, 17-Jun-1994


  1. I was a lookout on a Knox class frigate in the China Sea in 1990, all sonar and cic gear was going, didn't recognize it at first, but it was a camo sub riding the surface like he was playing with us, none of that asw gear picked him up.

  2. CNO,


    1) The key unclassified “take aways” from the Falkland’s war: “San Luis was free to patrol and this caused the British task force to be on the defensive at all times. The British expended most of their ordnance on suspected contacts, most of which were false contacts caused by the ocean's many anomalies.”

    2) Notable public examples of submarines penetrating the protective screen of warships:
    - 2006 USS Dallas versus HMS Illustrious during a naval exercise in the Gulf of Oman.
    - 2006 Chinese Song-class versus USS Kitty Hawkin the Sea of Japan
    - 1984 Soviet Victor-class submarine versus USS Kitty Hawk in the Korean Peninsula (the carrier actually collided with the sub).
    - 2007 Canadian HMCS Corner Brook versus HMS Illustrious in the Atlantic.
    -1974 unidentified Soviet SSN photographing the “USS Nimitz” (the photo was of a real USN carrier, but the Nimitz was in the yards at the time).

    3) The best way to conduct an ASW campaign is to first sink as many in port as possible, then to destroy or mine the harbors that support the submarines, then to destroy the repair and logistics ships (even SSNs have to replenish torpedoes, and take on food and spare parts), and lastly to hunt down individual submarines.


    1. GAB, I intentionally ignored reports of subs penetrating defenses during training exercises. While a sub penetrating a carrier's screen in an exercise gets attention, what we don't know is how many times they failed. Absent total records of training results, I can't draw any valid conclusions. In addition, training is often set up to try out various tactics and the scenarios are frequently set up to artificially favor one side or the other. Likewise, with the example of the Soviet sub photo of the carrier, how many Soviet sub attempts failed? I considered the Chinese example only because the Chinese sub is considered so inferior that it should have been an "easy" detection and thus tells us something about Navy ASW.

      I'm not familiar with the Victor/Kitty Hawk incident. I'll have to look into that one. Thanks!

      Your third point about conducting an ASW campaign is spot on. One can't help but wonder why we aren't devoting more effort to mining of enemy ports. For example, the AF is not going to be able to mine Chinese ports across a thousand mile A2/AD zone. We need a clandestine mining capability (submarine?).

  3. "The British sank the Argentine cruiser but achieved nothing further despite having six subs in theatre."



    Once again, the author puts forth an extremely shallow analysis which completely misses the main point: the Royal Navy submarine service essentially defeated the Argentine Navy when it sunk the ARA Belgrano.

    After the Belgrano was sunk on May 2nd, all of the Argentinean Navy's major surface combatants ran back to port. They didn't venture more than 12 nm from the mainland for the rest of the war.

    This included its sole aircraft carrier - which fielded almost as many fixed-wing aircraft as the entire South Atlantic Task Force. It also included several modern Exocet armed destroyers -- which could have made things very difficult for Admiral Woodward and company.

    So yes, those six British submarines achieved very little tactically in terms of ship sinkings after 5/2/82... because there weren't any targets left!!!

    But in strategic sense they broke the enemy's will and confidence. and negated his striking power. All with a spread of WW2 era torpedoes.


    1. (Sorry - last part of my comment got cut off...)

      Labeling what the British submarine force did during the Falklands War as "influence" grossly underestimates what they did. The RN submarines had operational and strategic impacts.

      Consider what would have happened if there were no RN submarines and the ARA Belgrano hadn't been sunk:

      The RN would have to fight through the Argie main fleet while 1,000s of miles from bases. The Skyhawks on the Veinticinco de Mayo and Exocet armed destroyers could have been a real problem, since even a damaged ship was a liability for the Brits.

      One might even argue that had the Argentinean Fleet had simply lurked in the background as a "fleet in being" - rather than running back to port - it could've had big impacts since it would've forced the Brits to previous divert ships from AAW screen.

      The Argentinean Navy responded the way they did after 5/2/82 because they knew they were overmatched. This illustrates how devastating even handful of modern SSNs can be against a Navy with little/no ASW capability.

      I would say similar parallel exists between China and US. We've got them grossly overmatched with our 50+ modern SSNs, while their ASW technology and training is decades behind.



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