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Lessons from Sweden’s Sub Hunt


The Swedish navy was pushed into its largest anti-submarine effort since the close of the Cold war last week.

For six days, it hunted for an unknown foreign submersible, likely from Russia, spotted several times off the coast close to the capital of Stockholm.

The Swedes called off the search on Friday without finding the mystery craft, but reportedly collected a trove of intelligence information for further analysis.

The search for a mystery submersible says much about the state of the Swedish navy in particular, and European fleets in general. It should also prompt a new effort to address the need for high-end warfighting capabilities across European navies.

The Hunt

Swedish sailors hunt for mystery submarine last week. Photo via ABC News

Swedish sailors hunt for mystery submarine last week. Photo via ABC News

Called an intelligence gathering operation—the effort off the coast of Stockholm lasted for nearly a week and included surface combatants, helicopters, ground troops (to sweep the islands in the Stockholm archipelago)—and more than likely one or more of Sweden’s air independent propulsion (AIP) attack submarines.

The mystery deepened when Sweden’s largest daily, Svenska Dagbladet, reported that the Swedish signals intelligence agency had intercepted emergency communications between a transmitter off the coast of Sweden and Kaliningrad—the home of Russia’s Baltic fleet—which suggested that the intruding submarine might be in distress.

A Russian merchant vessel, the NS Concord, circled just outside Swedish territorial waters throughout the operation, leading many to think that it was serving as a mother ship, and that the Swedish navy was tracking the scent of a Russian mini-submarine far inside Swedish waters.

There are several theories to what this mini-submarine could be doing so far into Swedish territorial waters, including that it was an exercise under real operational conditions for Russia’s naval special forces, or that the mini-submarine was deploying or replacing sensors in order for the Russian Baltic fleet to be able to monitor the movements of the Swedish navy in and out of their bases.

The most likely explanation seems to be that the mini-submarine was there to observe the multinational naval exercise Northern Archer, in which Swedish, Dutch, Danish and Polish naval units met up for training, including anti-submarine warfare (ASW).

The operation was called off after six days of intense efforts, with no visible results—although the Swedish armed forces say they have collected a trove of intelligence that now needs to be further analyzed. Regardless of the final outcome, the ASW operation says much about the Swedish and European navies, and the emerging maritime environment in and around Europe.

ASW in the Baltic Sea Then and Now


This was far from Sweden’s first ASW operation. During the 1980s the Royal Swedish Navy conducted a number of prolonged and intense operations against suspected Soviet submarines in and around coastal areas in the vicinity of naval bases and defense installations.

Some operations even included the use of live weapons against subsurface contacts. The most well known incident during this period is the so-called Whiskey on the Rocks grounding, when a Soviet Whiskey-class submarine ran aground only a few nautical miles from the inlet to the Swedish naval base in Karlskrona.

The Soviet sub was eventually towed into international waters by the Swedes, after a tense stand-off between the Swedish military and the Soviet Baltic fleet. The incident is now remembered in Sweden as perhaps the most important moment in the country’s Cold War history.

ASW helped define the Swedish navy during this period, and over roughly two decades the Swedes built up a muscular ASW force that could detect, target and attack submarines from above, on and below the surface. That generation of Swedish naval officers was essentially forged during the grueling ASW patrols off Sweden’s east coast.

Subsurface sensors and mine lines were strung across likely passages in and out of Stockholm, vital ports, and naval bases. That the Swedes attained so few tangible results says less about their ASW proficiency than about the forbidding conditions in the Baltic Sea, where the shallow depths (with an average of less than 200 feet), brackish water, and large archipelagos combined to make sub-hunting a tricky and frustrating proposition.

The Swedish submarine force used the same conditions to great effect. The skills, tactics, and technology honed in that environment made the submarine HMS Gotland a tough adversary for the U.S. Navy between 2005 and 2007, when the Swedish submarine was homeported in San Diego with its crew, to serve as an opponent during U.S. Navy ASW exercises.

However, the operation last week served as a stark reminder that the Swedish navy has changed considerably over the past two decades.

The Swedish ASW force that left port to hunt for the suspected submarine was in some ways more capable (including the stealth corvette HMS Visby), but considerably smaller than the force Sweden put to sea in the 1980s.

Since the Cold War, Sweden’s surface fleet has shrunk from 34 combatants to only nine and from 12 attack submarines to only five. To boot, Sweden scrapped its ASW helicopters a few years ago, and the replacement platform is not due to enter service until 2018 at the earliest.

While Swedish warships and submarines are all high quality, the navy has now reached a point where quite arguably quantity has become a quality in its own right, and the small numbers hamper the navy’s ability sustain operations for any longer period of time, or the ability to surge presence in a given area.

Furthermore, the Swedish navy has spent hardly any time on developing and exercising ASW tactics over the past decade. Instead, it has focused on expeditionary operations in concert with NATO, the European Union and the United Nations. Swedish units have participated in the naval embargo off Lebanon in 2006, and have also sustained a long commitment to the counterpiracy operation off the Horn of Africa. Much of the training and exercising in the past decade has been focused on supporting these types of maritime security operations.

European Navies and High-End Naval Warfighting

This development makes the Royal Swedish Navy in no way unique among European navies. There has been a general trend of a declining number of hulls in European navies, along with a focus on maritime security operations and supporting operations ashore. Along with the aforementioned operations, European navies have also contributed to operations Active Endeavor and Unified Protector in the Mediterranean and the removal of Syrian chemical weapons via the sea.

While all were important efforts they were focused on either the lower end of the maritime threat spectrum, or in support of operations ashore. And some have even gone further than the Swedes in optimizing their militaries for expeditionary operations and “small wars.” Denmark, for example, scrapped its entire submarine force in the early 2000s, in order to husband the resources needed to craft a more expeditionary navy, which has admittedly acquitted itself quite well in, for example, counterpiracy efforts off the Horn of Africa.

Broadly speaking, European navies believed there was little need for ASW and other types of high-intensity operations in age where the United States was unchallenged, Russia was weak, and the major threat against Western security resided in caves in the Hindu Kush. This analysis of the threat environment is not necessarily incorrect, but perhaps only partially true.

European navies and coast guards do indeed deal with very immediate maritime security concerns in the Mediterranean and the Arctic on a daily basis, ranging from large flows of seaborne illegal immigrants to the possibility of oil spills in the fragile Arctic.

A More Competitive Maritime Environment

Swedish sub Gotland at Naval Station San Diego, Calif. with USS Ronald Reagan (CVN-76) in the background. US Navy Photo

Swedish sub Gotland at Naval Station San Diego, Calif. with USS Ronald Reagan (CVN-76) in the background. US Navy Photo

But the recent events in Sweden’s waters strongly suggests that with an ever more assertive Russia, high-end capabilities will be as relevant in the future as they were during the Cold War, and must be developed and maintained alongside the maritime security missions taken on since the 1990s.

Even without worries about Russia, European naval leaders are well aware of China’s emerging sea power, and that the global maritime environment is set to become more congested and competitive than perhaps ever before.
Beyond the Baltic Sea, Russia is also increasingly active in both the Black Sea and the High North.

To respond, NATO (and the United States) should consider doing an ASW exercise together with its Swedish partner in the near future to show an alliance naval presence in the Baltic Sea, and that the transatlantic community is responding to the changing maritime security environment. Thankfully, NATO already seems to be making some efforts in this regard, as the recent naval exercise Noble Justification did indeed include elements of high-intensity combat training.

The hunt for the mystery submarine should also serve as a wake-up call across the European and U.S. naval communities to not assume a benign maritime environment in and around Europe in the coming decades.

  • SolidBro

    The country started to go downhill when they disbanded the Swedish Bikini Team.

  • James Bowen

    I think it is interesting that we read so much about the decline of European fleets, when the decline of the U.S. Navy has been at least as dramatic.

    • matimal

      Says who?

      • James Bowen

        Look at what our fleet size was in 1989 and compare it to now. Then we had 600 ships, now we have 289 (and whether some of those should be counted as contributing to combat strength is questionable–see below about the Perry Class frigates for example). We now have just over half the number of SSN’s and maybe a third the number of SSBN’s as we did then. The surface fleet has seen similar declines. And those numbers don’t even tell the whole story. We have retired all of our best aircraft (the F-14, A-6, and S-3) and “replaced” them with the jack of all trades master of none F-18, which was originally an Air Force reject (not that it’s a bad plane, but it’s certainly not the equal of the F-14 in fleet air defense). While our shipboard air defense systems are pretty good (so far as we can tell in peacetime), our anti-ship weapon systems are a joke. The Harpoon, at Mach 0.8 with a 500 pound warhead, hardly compares to an SS-N-19 at Mach 3 and with a 2000 pound warhead (plus nuclear variants). Additionally, for the last decade the Perry-Class frigates have gone to sea without missiles, their launchers having all been deactivated around 2005. Our Mark 48 ADCAPs are good weapons, but we don’t have enough of them.

        • Dan J

          Wow, that is really interesting James. Can you recommend any further reading on that? Thanks for sharing!

          • James Bowen

            You are welcome. The information can be found in a lot of places. Perhaps the most simple way to look it up would be to look at the most recent issue of the U.S. Naval Institute’s Guide to Ships and Aircraft of the U.S. Fleet and compare it to a edition from the early 90’s. Comparing current issues of Jane’s Fighting Ships to previous issues from that period would show this as well.

          • Dan J

            Hi again James! Thank you for this further information. I have heard some about this (little bits and pieces here and there). I know that when I was in the Air Force they were doing a big cutback on troops at that time (the technical term was “force reduction”). A lot to ponder here. Thanks again!

          • James Bowen

            You bet!

        • allbuss84

          Not to mention that the DD 1000’s guns can outrange a harpoon missile… The US ships may be sunk by enemy missiles before they can even shoot back.

          • James Bowen

            Absolutely. The range of many air-launched anti-ship missiles exceed that of the F-18, so our carriers are vulnerable to potential enemy air forces from standoff range.

        • m007368

          Its not as negative as you convey. There are rough spots but there will always be rough spots.
          **FF(G?)s will all be decommed this year. We could have done this better but we didnt. They will be gone.
          **DDG1000 will come online with firepower to rival BBs and will greatly exceed BBs firepower once railguns are deployed in the next decade.
          **DDG51s continue to be upgraded with massive ASW improvements (AV-15, MH-60R, Multi-modal sonar bouy systems in tandem w/ P-8s)
          ***PCs – massive weapons upgrade and used to replace DDG requirements in Arabian Gulf. 10 on station under CTF 55. Bad day for FAC/FIAC especially when supported by USAF, USN, and USA close air support.
          **CVNs – Are being turned into massive ASW machines with the inclusion of LAMPS high end datalinks, complete Zulu (Xray module) remanning/redesign, AW/STG increases, and a ton of MH-60Rs (w/ senior pilots – the whole squadron deploys
          instead of a OIC)
          **FORD CLASS CVN – Expensive, incremental advancements over Nimitz. My favorite part PAWDS (using plasma to incerate trash and recyclables).
          **UCLASS- CVN Drones. Reduced crew rest issues, higher endurance, larger payloads, and significant improvements in boarding rates/combat sorties.
          **BAMS- Global Hawk meets Navy. Continous realtime sensor package with anything from high rez camera, signal exploitation gear, AIS receivers, etc. Its awesome.
          **VLS Capable Hypersonic ASCMs – In development. See
          “Offensive Anti-Surface Warfare (OASuW) Weapon Dev program” or LRASM programs. DARPA and USN (OPNAV N96) are not ignoring the problem.
          **Weaponized Lasers (LAWS on AFSB-I PONCE)- Speed of Light “round” (solves CIWS issues), “infinte ammo”, cheap ammo, and will continue to improve in power/responsiveness with material science developments.
          ***E-2 upgrades. E-2 more comms, better radar.
          ***P-8s. Definetly different than the P-3 and we lost some capability due to speed/altitude issues. But the thing is a ASW/MARPAT monster.
          **UAVs- Number of other UAVs are currently active and deployed across the fleet but havent added a huge amount of SA or operational capability. We are getting there but it takes time.
          **Railgun – This thing will completely revolutionize coastal presion strike but the material science challenges are still causing issues.
          **F35- Not sure yet how well these guys will play.
          **LCS-Still no OIC modules but it will serve as an expensive but capable ASW, MCM, or counter FAC/FIAC SUW (eventually it may have fully capable ASuW ASCMs).
          **No real tangible plan for MCMs yet. If LCSs Module works, then we are good to go.
          **Need more subs.
          **Need replacement for SSGN. May be the Virgina class modules but nothing really even equivalent yet.
          Thats probably enough examples. I am a surface guy by trade so feel free to throw stones especially if I am missing a program of record or a recent change. Apologize for no significant examples of our efforts in cyber/EM spectrum, both areas are becoming as important than the traditional warfare areas.

          • James Bowen

            The lasers are definitely an interesting development, but that is where the good news ends. The rail guns have a lot of potential, but they have not even been built yet, let alone tested. Nothing else here really changes much. There does not appear to be much of a sense of urgency to develop that new anti-ship missile (the stated goal is 2024–the need was there years ago, let alone now). Also, I thought the DDG-1000’s (of which there will be only three) had firepower of 2 155 mm guns and some 80 missiles, roughly comparable to the DDG-51’s. Is there something I missed? Most importantly, none of this addresses the problems of too few ships and the disappearance without replacement of our best airframes.

  • David Brinton

    So, let me see if I have this right. They found nothing, but have decided that means they need to upgrade their naval capability so the next time nothing is there they will be more certain nothing is there, or will they then demand more upgrades? How much does one need to upgrade in order to find nothing?

    • Claes Henrikson

      You got it wrong, there. We didn´t “find nothing”. We found “something”. We just couldn´t force “something” to break surface. That´s why the need to upgrade.

      • David Brinton

        LOL, no, you thought you heard something and assumed what it was, but when you turned on the lights it wasn’t there anymore. My 5 year old has the same issue with his monsters.

        • Claes Henrikson

          Oh. He has pictures of them, has he? We do.

          • David Brinton

            You mean those grainy pictures of something in the distance that could just as well be the Loch Ness monster? LOL, pictures, yeah right.

          • Claes Henrikson

            It wasn´t Nessie.
            And I seem to recall that the USN had a hard time locating HMS Gotland when they trained together. A very hard time.

          • David Brinton

            > It wasn’t Nessie.

            How can you be sure? I saw the picture. It looked just like the ones of Nessie. It wasn’t a sub. They looked for a week and found nothing. Only Nessie is that adept at evading searchers.

          • Claes Henrikson

            Photo interpreter, too? Wow.
            It was a sub. They hunted it for a week, but couldn´t get it to Surface. Not only Nessie is adept.
            May I ask, Sir, what is Your reason for denying the presens of foreign vessels in Swedish waters?

          • David Brinton

            > It was a sub.

            Its was a kid paddling around on a styrofoam surf board. They didn’t find a sub because there wasn’t one there.

            > reason for denying

            Because I know the truth. This is all a scam to grow the NATO budget and prevent the U.S. military industrial complex budget cuts from taking full effect.

            You fools keep falling for these scams and paying whatever the military wants to grow ever bigger, as if Russia would attack Sweden. How absurd.

          • Jim B.

            So David what it gets down is you are a Conspiracy Theorist. Istead of the “US Military Industrial Complex and NATO” getting all the money where would you see it go? To more failed wefare programs that are completely broken, or a completely broken (from the start I may add) Obama Care?

  • zencowboy61

    Total BS…And if it was true and they couldn’t find them shows you how well they are trained and capable as a navy…total fail…

  • Jerry Casaday

    You have to wonder if that Russian merchant ship was testing an operating system for remote control of a drone submersible. Such a platform could be extremely stealthy, because with no crew to sustain, it could be powered down on the bottom for as long as needed to shake the searchers, then be reactivated to drive the Swedes nuts. I’d be interested to know if the Swedes were picking up any unexplained emissions from that surface ship at the time.