Midget Submarines at Kalbådagrund

The following chain of thoughts started when a strange place name appeared in a blog post by Swedish defence blogger Jägarchefen. Further research led to a theory, the reasoning behind which is detailed below.

The CIA file

The open archive of CIA FOIA files include a large number of documents dealing with Soviet vessel movements in the Baltic Sea. Most of these are rather unspectacular, doing little but dispelling the idea that intelligence work is anything like a Bond-adventure. There are however exceptions, like file number CIA-RDP80-00810A007600280010-0, dated 13 October 1955.



‘Kalbod Shallows light’ likely refers to Kalbådagrund lighthouse southeast of Helsinki, where a caisson-type lighthouse was erected on a dangerous shoal in 1952. Here, a flotilla of 10 to 12 midget submarines passed by under tow in the evening of 27 May 1955. But where did they come from, and why were they outside of Helsinki in 1955?

The War Trophies

In the closing years of World War II the surface units of the German Navy faced pressure from ever increasing numbers of Allied aircraft and naval ships. The logical answer was to start using the submarine force also for missions closer to shore. This called for smaller vessels, capable of manoeuvring in the more confined waters of the Atlantic coastline.

Probably the most successful of the host of different craft created was the Typ XXVII B, better known as Seehund. The 12 meter (~40 feet) long submarine had a crew of just two man, and as opposed to most midget submarines it wasn’t fitted for operations with limpet mines or divers, but was armed with two G7e torpedoes, the standard weapon of the German submarine force. As the submarine was so small, these were strapped on externally. They were sighted through a fixed periscope, located in the forward part of the tower.

Source: Uwe Ernst/Wikimedia Commons

The Soviet captured a number of these vessels, though exactly how many remains unclear. Some sources claim that only a very limited number was in use[1], but most list a significantly larger force. The British Royal Navy’s Director of Naval Intelligence in 1952 commented that the Soviet Navy “acquired some 50-70 ex-German, Italian and Japanese midget submarines after the war, but it seems likely that they have produced their own post-war version, which, from reports, seems to incorporate parts from the design of all above. There are also reports which indicate training in midget S/Ms in the Soviet Navy at the present time.”[2] The CIA is also looking at a similar number, stating that the Soviet Navy had “at least 70 midget submarines” in service in November 1953, of which around 20 are ex-German Seehund vessels, the rest being an “improvement on the previous type and made use of German SEEHUND plans”. These Soviet improved Seehunds were built after 1947. Notable is also that CIA has no information “regarding specific bases for these submarines”, but they also concede that they can be operated from “any existing base”, or from a properly equipped support ship.[3]

Other sources support this picture. The Swedish intelligence service was also on the trail, with the so called T-office reporting in 1946 that “On pier in Kronstadt harbour lies some midget submarines, probably ex-German”. Russian naval historian Vladimir Shcherbakov notes that the Seehunds “were used rather intensively”. Swedish historians von Braun and Gyllenhaal puts the confirmed number of complete Seehunds captured as “at least two”.[4]

But how did the Soviets manage to build up a sizeable force from war trophies and modified designs?

The Shipyard

The majority of the Seehunds were built at Schichau-Werke in what was then Elbing in East Prussia (today the Polish city of Elbląg). The yard escaped relatively unscathed during the war and the immediate post-war, and in 1947 it was one of few factories listed as being in service, having just delivered the first new built vessels postwar (these being torpedoboats).[5] In the same year, it was reported that Soviet (and Polish) companies tried to recruit former “technicians, employees, and workmen” of the yard in East Germany. Most refused, but “a certain number” accepted and left for East Prussia, presumably to work at the former Schichau subsidary at Contienen, which had produced parts for submarines and minesweepers during the war. The Contienen yard as well was reported to have seen relatively little damage during the war, and escaped dismantling after the Soviet forces occupied it.[6]

In 1949, the operations at Schichau-Werke in Elbing was reported to have risen back to 80 percent of its wartime capacity. Around 120 German prisoners of war were still employed as “skilled workers”, pointing to the fact that the earlier attempts to recruit workers hadn’t produced enough volunteers. The yard featured a modern welding current distribution system, and an expansion program of the yard was planned, the aim being to double the capacity by spring 1951. Interestingly, the CIA file reporting this includes a comment that the recent information “essentially confirms” other information on the shipyard, and that “it appears likely that no vessels other than small submarines are now being constructed there”.[7]

To remember is that during the last six months the yard was in operation during the war, the number of Seehunds produced in Elbing seems to have been over 100. If the CIA report was correct, even at 80 percent production the yard would have built 50 new vessels in a matter of months. But where did they go?

The Peninsula

When the Continuation War ended, amongst the Soviet demands was one which prime minister Paasikivi described as “horrendous”. The Porkkala peninsula was to be leased to the Soviet Union for 50 years, i.e. until 1994.

Detail of the map from the armistice agreement showing the area to be leased to the Soviet Union. Note Helsinki in the upper right corner. Via Wikimedia Commons


This replaced the earlier deal under which the Soviets had leased the Hanko peninsula further west after the end of the Winter War, and included a very favourable transit agreement. Under this, the Finnish customs authorities had no right to inspect the cargo holds of trucks or trains transiting  between the naval base and the Soviet mainland. Soon it became apparent that foul play was involved, as sometimes the trucks could make the trip in four hours, while sometimes the time on the road stretched to up to ten hours. A SIGINT station for listening to Finnish radio communications was created at the Majvik mansion, today a meetings and convention hotel, and suitably located on top of a large hill close to the shore. In the early 1950’s the station was manned by 24 NCOs and four officers, working in three shifts to maintain a constant surveillance of the Finnish radio networks. The station was not part of the naval base’s chain of command, but instead reported directly to the intelligence section of the Leningrad Military District in all matters.[8]

In addition to being a naval base, the most well-known vessel of which was the monitor Vyborg (former Finnish coastal defence ship Väinämöinen), the base also played a significant role as an intelligence hub. A number of arrests were made and dead drops uncovered in connection to the transit traffic mentioned above, including that of air force captain Martti Salo of the aerial photography unit in Tikkakoski. It appears that the main responsibility for intelligence gathering in Finland was placed upon GRU, likely in part due to the heavy use of the military trucks travelling to and from Porkkala.[9]

Amongst the most important units of the bases was its intelligence unit. In a report covering the third quarter of 1945, the unit had not only counted and identified the nationality of all vessels sailing  past the base (1 371 vessels in total), they had also, as a collaborative effort between the “officers of the base’s staff and units situated in Finland”, gathered information and systematically categorised this into a file covering multiple aspects of Finland, including:

  1. Much information on the Pansio naval base
  2. Information on the Army and Coastal Artillery units located in the Turku region
  3. A description of the oil depot being built in Naantali
  4. A description of Finland’s coastal defences
  5. Information regarding the Finnish coast guard and all its bases

The information gathered also went down to the individual level, covering 96 Finnish officers, including their service records and personal evaluations.[10]

The continuous building of trenches and bunkers as well as the naval activity came to an abrupt halt in 1955. In September, Khrushchev suddenly informed Finland that the base would be returned. This doomed the heavily fortified base, and all defensive works were demolished, including the almost-finished command bunker Los which stretched over 100 meters through the mountainside. The personnel, numbering over 15,000, was transferred away, as was the tens of naval vessels and small crafts that were stationed there.

But did the intelligence gathering extend to other methods as well?

The Theory

My theory is that the convoy sighted on an easterly heading south Helsinki in May 1955 indeed did consist of Seehund-type submarines (either ex-German or modified new-builds). I further believe that they were in transit from Porkkala naval base to Kronstadt, either due to a unit transfer (possibly due to having received early notice of the upcoming closure) or after a finished exercise/mission.

In other words: in addition to the surface and land-based units known to have been stationed there, Porkkala played host to a unit of midget submarines in the first half of the fifties.

These have been either exercising or permanently stationed there. Considering the unique nature of the Finnish archipelago, it isn’t far-fetched to conclude that any exercises held there were made with an eye towards either the Finnish or Swedish coast. Furthermore, considering the extensive intelligence work done by the GRU out of Porkkala, it is likely that the submarines would have participated in covert intelligence gathering against Finnish targets. Especially as the intelligence work is known to have in part been directed against naval and other coastal sites

Are there alternative explanations? Certainly. The submarines might have been misidentified barges, or they might have come from Tallinn and turned north to get around heavy weather. However, the most likely explanation in my opinion is that the vessels were transiting from Porkkala to Kronstadt:

The sketch captures the general outline of the Seehund well, including the approximate location and general shape of the conning tower and the location of the fixed periscope. Riding high would be explained by the lack of torpedoes, which are unlikely to have been carried during transit.

It is assumed that the Soviet Navy operated a number of Seehund-type submarines, including of an improved design. The Soviets did capture one of the main production sites of the Seehund, and this resumed operation relatively soon after the war, with part of the workforce being German. The ability to produce the improved design appears to have been there.

The Seehunds were sighted in Kronstadt, as well as in other parts of the Baltic Sea during the time frame in question.

Porkkala held an important dual role as a naval base and intelligence gathering hub. The later was led by GRU, with some units being directly subordinated to the Leningrad Military District. Amongst the targets for the intelligence gathering operation were Finnish Navy, Coast Guard, and harbour locations. Using midget submarines for covert intelligence gathering would fit that pattern.

The location in the northern half of the Gulf of Finland also seems more likely for a unit coming from a Finnish port than from a location on the southern shore of the Gulf.


A special ‘Thank you’ to Jägarchefen and Lars Gyllenhaal!

[1] http://www.hisutton.com/Secret%20History%20-%20the%20Soviet%20submarine%20gap.html

[2] Register No. P.D. 054/52

[3] CIA file CIA-RDP80-00810A002800340004-3

[4] All quotes in paragraph from: J. von Braun and L. Gyllenhaal, Ryska elitförband och specialvapen, 2nd edn., Stockholm, Fischer & Co, 2016

[5] CIA file CIA-RDP82-00457R001100020007-4

[6] CIA file CIA-RDP82-00457R000800070004-6

[7] CIA file CIA-RDP82-00457R003300540006-7

[8] J. Leskinen, ‘Porkkalan tukikohta 1944-1956’, in J. Nieminen (ed.), Porkkala – Tapahtumien keskellä, Maanpuolustuskorkeakoulun Sotahistorian laitos, 2009

[9] K. Rentola, ‘Porkkala ja tiedustelu’, in J. Nieminen (ed.), Porkkala – Tapahtumien keskellä, Maanpuolustuskorkeakoulun Sotahistorian laitos, 2009

[10] L. Amirhanov, ‘Neuvostoliiton Porkkala-uddin laivastotukikohta kylmässä sodassa 1945-1956’, in J. Nieminen (ed.), Porkkala – Tapahtumien keskellä, Maanpuolustuskorkeakoulun Sotahistorian laitos, 2009

Spy Ships and Naval Intelligence

During the height of the Cold War, the ’Soviet Trawler’ was an expression in naval circles. Solitary Soviet flagged trawlers had a tendency of appearing on the scene of almost every major NATO naval exercise, and then idly throttling around in the general area until the end of the exercise.

Soviet trawler Gidrofon and the USS Abnaki ‘ATF 96’ in 1967. Picture apparently taken from the carrier USS Ranger ‘CVA-61’. Source: USN/Wikimedia Commons.

The reality was that these were thinly veiled intelligence gathering vessels, or spy ships as they are generally known. While the Soviet Union could, and did, use regular naval vessels, such as destroyers, to perform the intelligence gathering mission, the converted deep-sea trawler offered several notable benefits. The basic designs were created for extended stays at sea, offering the small crews at least a minimum level of comfort for their sometimes long missions. The vessels also featured large enough hulls to be fitted with the necessary intelligence gathering equipment. Chasing away ‘civilian’ vessels always held a risk of creating bad publicity if something went wrong, and being unarmed they had a far greater choice of ports when it came to bunkering. They were also far cheaper to operate compared to major surface combatants.

Considering all factors, it is no surprise that the trawlers became the instrument of choice for various kinds of operations. Their methods of intelligence gathering included both visual, i.e. guys with cameras and binoculars documenting what the NATO ships were doing, as well as electronic and signal intelligence, i.e. antennas recording radio communications and signals sent out by radars and other systems onboard the ships.

Now, with the highly political joint Finnish-Swedish-US air exercise to be conducted outside of the Finnish coast, suddenly a Panama-flagged, Russian-owned, seismic research ship has arrived in the exercise area.

What then, you might ask, is a seismic research ship?

Seismic research is conducted when ships try to figure out what is under the seabed. Normally, they do this to look for oil and gas deposits, which is the reason why there are quite a number of these highly specialized ships operating around the world. In practice, the ships tow a number of streamers in an orderly pattern behind the boat. These can be up to 10-20 km long, and are equipped with either emitters or receivers. The emitters send out a signal, the echo of which is received by the receivers. Based on the received signal, a computer then processes the data and draws a picture of what is underneath the bottom of the ocean, a bit like the use of sonography by medical professionals.

The principle of seismic mapping by ship. Source: U.S. Geological Survey

Why on the earth the vessel suddenly has appeared in these decidedly oil-less waters is a matter of speculation, but noteworthy is the fact that mapping of the seafloor in Finnish waters requires a permit. It is also unclear if the seismic measuring equipment is onboard, or if something else occupies the area normally reserved for 100+ km of seismic streamers.

Let’s just say, coincidences does happen, but I wouldn’t count on this being one of them.

Update on the Red October-incident

Yesterday I published a brief text pointing out that not all submarines in the Baltic Sea are Russian, and that not all underwater activity is submarines. This will be a brief update on what has happened since.

The major news was when Swedish newspaper Svenska Dagbladet reported that a signal emerging from the archipelago outside of Stockholm had been sent on a Russian Navy distress channel. When the search operation got underway, there was renewed traffic, which was encrypted, and a transmitter located in Russian Kaliningrad answered. This was the first evidence that decidedly pointed towards Russia as the country of origin. This could also explain the, in my opinion, rather strong and decisive response by the Swedish Navy when the first visual sightings occurred.

Representatives of the Swedish Defence Forces have denied that they have received knowledge about a distress signal, although the exact wording leaves the possibility open that A) the info has been distributed on a strict need-to-know basis, and as such is not available to the officers involved in the operation, or B) the interpretation that a signal on a known foreign military channel used for distress signals does not equal a known distress signal. They have also clearly stated that they do not know the country of origin or exact nature of the underwater activity, and as such they will continue to refer to it simply as “foreign underwater activity”. Most importantly, it has been confirmed that three visual sightings have taken place, and that the operation will continue for a number of days. Imagery from one of the sightings has also been released. The picture is grainy, but could be interpreted to show some kind of a midget submarine, e.g. the Russian Triton NN.

One of the pictures released by the Swedish Defence Forces, showing a man made object traveling on the surface, before vanishing under it. Source: http://www.forsvarsmakten.se

The question of where the mother ship is located has been focused on the Russian-owned Liberian-flagged crude carrier NS Concord. The ship has been anchored outside of St Petersburg since the beginning of May, acting as a floating storage. Last week, it set sail and sailed to a position right outside the border of Swedish territorial waters, where it has since loitered. To begin with its AIS-data gave the destination as Danish Straits, but today this was changed to Primorsk. When the tanker suddenly found itself in the limelight, the Russian research/sea survey vessel Professor Logachev suddenly headed out to sea, destined for Las Palmas(?). It remains to be seen if this vessel will make a stop outside of Stockholm, but the timing seems somewhat suspicious. The Logachev also happened(?) to be traveling in the middle of the three-ship Dutch naval flotilla heading home from Tallinn, with the Walrus-class submarine HNLMS Bruinvis probably not far away either.

In Finland Charly Salonius-Pasternak, Sr. Research Fellow at FIIA, noted that Finland’s stance on the issue will be noted in Sweden, and called for our politicians to make a clear statement in support of Sweden. Otherwise it will affect the possible deepening of Swedish-Finnish military co-operation.

This in turn made Carl Haglund (SFP/RKP), Minister of Defence, answer that we will wait and see, and that if the allegations are true, this is “very serious”. On a direction question he said that we are currently not planning any assistance to the Swedish Navy, but if an official call for help comes, he would personally view it favorably. With regards to what kind of help we could send, he stated that options remains open, and would depend on what kind of assistance the Swedish authorities would be asking for. Salonius-Pasternak in turn noted that one can offer help even before someone asks for it, but this remark went unanswered.

As a further note, the hashtag #redoctober has become widely used with regards to the incident.