Miltiades Varvounis and Saiva Ziogaite
24 July 2001
This report deals with the incident in the North Sea during the night of 20/21 June 1940,(the data used by authors Edmund Kosiarz and Czeslaw Rudzki was from 20/21 June.The data used by Mariusz Borowiak was from 19-20 June) when the Polish Submarine Wilk collided with something.
Several books have been published, variously suggesting that Wilk hit a submarine, or a mine, or even a surface wreck.
The fact that there are two different official versions of Wilk's collision with an object, makes the matter more difficult to resolve.
It is worth mentioning that foreign writers invariably state the theory that Wilk hit the Dutch submarine O-13. Polish authors contend that Wilk hit the German U-122.
In my opinion, no-one has given a convincing reason for believing that Wilk hit one submarine or the other.
The lack of unanimity aroused my curiosity, and I determined to investigate this intriguing mystery as best I could, to establish whether it might be possible to reach a conclusion on the basis of all the available information I could unearth.
I have been researching this interesting theme since August 1997, and have found many interesting facts about this case. This first part deals with the story of Boleslaw Romanowski, First Officer of Wilk who was on watch in the conning tower when the collision happened. Romanowski wrote a book and articles about his memoirs during war, so we have a basic source for his version....
"I had the night watch until 04.00hrs. The night was dark and the sea very peaceful[...]
We were only doing 3 knots, so as not to leave a trace behind us. I was at my usual position on the left side of the conning tower, with powerful Barr and Stroud binoculars. The signalman was watching from the right side of the conning tower, and another officer was looking out beyond our stern. It was very quiet[...] Suddenly the signalman shouted loudly:
-10 degrees, a ship!!
I immediately saw the prow of a small ship. The distance was about 300 metres - too close to fire torpedoes.
"Collide" I decided quickly.
- Hard left! I shouted. - Full speed ahead! I said without taking my eyes off the observed thing.
The diesels suddenly roared loudly. Wilk was slowly picking up speed.
- It`s a U-boat! shouted the signalman.
At the same time, I saw the characteristic silhouette of a submarine.
Increase speed quickly! I shouted, - It is diving!!
Wilk was increasing speed and we could see the enemy boat desperately diving to avoid the imminent collision.
After reaching a speed of only 9 knots, the collision occurred. Our bow hit the U-boat in front of her deck gun, just as her deck had disapppeared under water and her conning tower was about to submerge. The impact was very powerful. Under my legs I felt a violent shudder, and heard a loud noise and also another strange noise too.
Looking behind I saw that the U-boat had disappeared from the surface, and only a lot of white foam could be seen, but it is difficult to say if the foam was coming from the rammed deck of the U-boat or from her quick diving.
- What happened? Shouted the captain, (Boris Karnicki), who had rushed to the conning tower.
- We ran down a U-boat sir!!![...]
The U-boat was more visible to us than we were to them, as we could see all of her silhouette, but they could see only our bow.
The German saw us at the last moment and made the tragic mistake of diving, instead of remaining on the surface and avoiding the collision by turning left. If we hit her deck, she was probably sunk. Who knows, maybe we turned her upside down and finished her off with our propellers.
But our propellers probably hit the U-boat's conning tower.
All night, and for weeks afterwards, the crew discussed the incident and wondered if the U-boat had been sunk, or was safe somewhere on the sea."
According to Romanowski's version, it is more likely that Wilk hit a U-boat rather than a Dutch submarine.
Let us examine the facts:
The important factors are the diving time and the deck gun.
First I would like to start with the diving time.
It is known that German U-boats had a big advantage in that they could dive very quickly - in less than 30-35 seconds - unlike Allied submarines which took 50 seconds or more to dive.
U-122 was a new type IXB U-boat, commisioned on 30 March 1940.
O-13, which was commisioned in the Royal Dutch Navy on 31 October 1931, took much longer to dive.
If we consider Romanowski's statement that Wilk was 300 metres away from the unknown submarine, and that the enemy`s captain saw the Wilk at the last moment and decided to dive, it is obvious that the submarine which was spotted must have had an ability to dive very quickly.
It is worth remembering that Wilk collided with the other submarine while Wilk's speed was still only 9 knots - a detail that proves how close Wilk and the other submarine were. 300 metres is a not a great distance. Wilk probably reached the other submarine in less than one minute - if not less than 40-50 seconds. (In fact, at 9 knots, it would have taken 65 seconds to cover 300 metres, but as Wilk was accelerating from only 3 knots, it would have taken her a bit longer than this to cover the 300 metres)
If lt. cmdr. E. H. Vorster, the Dutch commander of O-13, had seen Wilk at the last moment, he would have realised that it would be impossible for him to dive in time to avoid a collision, but with his quicker diving time, a German U-boat commander could make that risky decision, which was to prove fatal.
The Dutch submarine O-13 would not have had a chance to dive, and even if her captain did decide to dive, Wilk would have hit O-13 while she was still on the surface, and not disappearing quickly under the water, as Romanowski described.
Romanowski and the others on Wilk's conning tower stated that they saw a deck gun on the submarine they rammed. O-13 did not have a deck gun!!! (But U-122 did!)
O-13 had two 40mm anti-aircraft guns on the front of the conning tower.
A photograph of O-13 may be seen in Dutch naval historian Bram Otto's website at www.DutchSubmarines.com.
Another more interesting photo of O-13, courtesy of the Naval Historical Section, Royal Netherlands Navy, is published in Anthony J. Watts' book "Allied Submarines".
A caption above the photo says:
"Note the lack of a deck gun, and hatches protecting retractable 40mm mounts in fore and aft extensions of the conning tower."
In fact in this photograph, O-13's small guns are hidden, and no gun is visible in the conning tower, unlike the photograph in the internet site.
Some might say that Romanowski may have misidentified these anti-aircraft guns on her conning tower as a deck gun, but he was an experienced submariner, and is unlikely to make such a mistake. He was closely watching the unknown submarine all the time through binoculars, and could see her full silhouette from a distance of 300 metres. His view of the other submarine must also have improved as the Wilk closed to ram.
On the other hand O-13 could have hidden her 2X40mm guns. No one said that when a submarine surfaces, and at nights mainly, she must have her guns out of the hatches.
All Dutch submarines, with the single exception of O-13, had pennant numbers painted on the conning tower when the Royal Dutch Navy was operating from Great Britain.
The number O-13 is clearly visible on the conning tower in the photograph in Watts' book, but may later have been painted out.
(For some reason which is not clear to me at the moment, O-13 had her pennant number changed to N-13, and this is the number she was displaying when she left Dundee for her last patrol.]
We know that some U-boats had numbers and/or emblems painted on the conning tower, while others did not. (Pre-war photographs of U-boats, and those taken early in the war, show pennant numbers painted on the conning tower, but at some time during the war, the Germans must have made a decision to stop painting the numbers on the tower, as later photographs do not show numbers.
Neither Romanowski nor anyone else mentioned seeing a pennant number, or any other identifying symbol on the conning tower. If there had been such markings, surely Romanowski would have mentioned it. The fact that he did not, suggests that nothing was painted on the conning tower of the unidentified submarine.
These were the important and basic details of how Wilk hit - very likely 99% certainly - a U-boat, and not a Dutch submarine.
But things are not so simple. We have also another version of the collision that we will discuss in the second part... And also we will consider the possible positions of the both submarines (U-122 and O-13) since nothing is clear about U-122's route...
According to Bram Otto:
1) 12 June 1940:
O-13 left Dundee for a patrol near the entrance of the Skagerrak, around 57°N 05°E. She was lost with all hands were lost during this patrol.There are three possible explanations for the loss of O-13, the first option might be the most likely:
2) 13 June 1940:
O-13 struck a German mine near the Great Fisher Bank. German minefield 16B was located near 56°55N 03°00E.
3) 16 June 1940:
O-13 was bombed by two Arado aircraft from the German battleship Scharnhorst. The aircraft reported a position 400m north of 0-13's patrol area. It is more likely these aircraft attacked the British submarine Porpoise.
4) 20 June 1940, 00:25 hrs:
O-13 was accidentally rammed by the Polish submarine O.R.P. Wilk, whose location was reported to be 56°50N 03°37E, only 16miles from the estimated position of O-13. According to details described by Wilk's XO Cdr. Romanowski in his memoirs, it is unlikely the Polish submarine rammed the O-13.
Let us now look at the other official version of Wilk's collision. This report differs from Romanowski's story. According to [ADM 234/380] Wilk was in 5650N 0337E at 0025hrs on 20 June 1940 when she sustained a severe shock which lifted her stern right out of the water. At first this was thought to have been caused by the explosion of a mine, but it was later considered to have been caused by striking a submerged submarine. No flash or upheaval of water was seen, and members of her crew reported hearing a wire scraping along her hull immediately beforehand, so it is at least possible that she had a narrow escape from a German mine.
(On the other hand, perhaps this was the sound of a submarine's jumper wire scraping Wilk's keel).
After the collision, Wilk could only make 3 knots, and was thought to be badly damaged. She was 300nm away from Rosyth, and reached there on 25 June, four days later.
On being informed about this incident, British warships were sent to sink the damaged submarine and capture the crew, but Wilk never met these warships on her route home.
When Wilk reached Rosyth, she was welcomed by the British, and praised for sinking a U-boat.
That night a special reception dinner was held for Wilk's crew to celebrate their success.
Later the Wilk's crew were amazed to find that their submarine was not as severely damaged as they had thought. Both propellers were damaged; half of the blades were missing from the starboard propeller, and only one blade remained on the port propeller. The damage to her bow was not serious, but provided evidence that Wilk had certainly hit something. The collision damage was repaired quickly in Dundee, and Wilk left shortly afterwards for another patrol on 10 July.
A new British officer was aboard for this patrol, and Boguslaw Krawczyk had been replaced by lt. cmdr. Borys Karnicki as Commander of Wilk. The crew were wary of their new Commander.
The reports of the Polish submarines were written by British officers, as the Poles' command of English was generally not sufficiently good to enable them to write their own reports fluently in English.
Why do we have two different versions, and which one is correct?
This is difficult to say. The British officer who wrote the report of the collision may have misunderstood the description given to him verbally by the Poles, and written something rather different from what the Poles were actually trying to say. Maybe what happened was perfectly understood, and perhaps it was explained to the Poles that under British regulations, a collision was not a recommended method, and that the Captain or other officers could be Court Martialled, with career-damaging consequences.
There were rumours that the British had "jokes" about collisions.
When she reached Rosyth, the British obviously knew that Wilk had hit a U-boat, but unfortunately we have no details of the radio message that Wilk sent to her base, reporting the collision.
Could a collision have occurred without Wilk's officers knowing what they had hit?
If the answer is yes, then why is Romanowski's story different? Was it a cover-up to conceal inadequate watch-keeping? Had those on watch really seen nothing before the collision, and had Romanowski wanted to make the incident more impressive and acceptable by inventing a hypothetical U-boat to account for the damage that Wilk had sustained during his watch?
But it was not just Romanowski who claimed to have seen the submarine 300 metres away, and deliberately turned to ram it.
We now have new information from the two volume "Mala Flota Bez Mitow" (The truth about Small Fleet) by Mariusz Borowiak also dealing with Wilk Case.
Jan Jaworski the only crewmember of the Wilk still alive that was in that patrol wrote a letter to Borowiak after reading the first volume of Borowiak's book about the Wilk collision. His letter is shown on pages 379-380 of the second volume Jaworski wrote that Wilk hit a rock and when they reached port, a British officer (no name given) with the rank of Lieutenant-Commander examined the submarine and that Romanowski's theory is incorrect.
Borowiak also claims after Jaworksi's letter that a British commission found that Wilk hit a rock and not a submarine.
These of course are new facts and theories, but they are also not clear and somehow confuse the Wilk Case even more. Why did Jaworski wait so many decades (most of them were during the Communist era perhaps he did not want to bring his story to the surface for that reason) to say these things? Jaworski was not on the bridge when the incident happened so why does he think that Romanowski's story is incorrect? That unfortunately can never be proven, and also, Karnicki never questioned Romanowski's theory.
If a commission examined that boat as Borowiak maintains(no sources are given for the information on the commission but perhaps it came from the Polish Institute and Sikorski Museum in London - archives ORP Wilk MAR.A.V.27/6-7) why does the Admiralty still claim today that Wilk probably hit a submerged submarine? The Admiralty must no be taking the commission's findings into consideration.
It is interesting to examine in the first volume, (page 276) the letter Kontradmiral(Rear Admiral) Jerzy Swirski wrote to General Sikorski about that incident (archives of Polish Institute, IMPS, sygn MAR.A.V. 27/6) that states that according to the report of Borys Karnicki and the opinion of Division Command and also the Vice-Admiral (name unknown) that Wilk hit a U-boat and considering the damage to Wilk, the damage to the U-boat should have caused the U-boat to sink. In the last line of the letter Swirski mysteriously states: "I report that this incident is kept by the British Admiralty in secret."
This letter was written on July 5th when repairs were almost finished and Wilk was ready for another patrol and it confuses things even more
Since Jaworski and Borowiak talk about the commission, why did Swirski not write about its finding? Perhaps the commission reported their findings later but again, why were the Admiralty records not changed to mention the commission's findings? Why did the Polish public not find out about it until 1999?
It is also a mystery that Swirski would not know about details but that Jaworski, a simple sailor, would know so much about them... It seems that Jaworski, like Feliks Przadak (a sailor from another Polish submarine, Orzel) is exaggerating his story. Feliks Przadak claimed that a Dutch submarine sank Orzel. These stories written six decades after the fact seem to be derived from rumours rather than first-hand knowledge.
Also Borowiak's book contains correspodence between Jerzy Pertek (famous Polish author) and Hans R. Bachmann (a Swiss author) from 1969 about the Wilk Case. On page 280 of the first volume, Pertek states that "Personally I believe that it is possible that Wilk collided with a submarine [...] English Admirals told the crew of Wilk (after the incident ) that Wilk hit a rock (mud bank?). Very likely Wilk passed through a minefield [...] According to Wilk KTB there was an undersea explosion. These incidents are different from Romanowski's story."
Bachmann replied: [...] there is no mention of a submarine in the Wilk's KTB, but on the other hand Romanowski and a signalman claimed that they saw a submarine [...] but it is very possible that Wilk escaped from a mine with minor damages."
If Wilk had hit a mine, it is hard to imagine how she sustained damage only to her bow and propellers.
One would have thought there would also have been other serious damage to her hull between the bow and stern.
The nature, and the positions of the damage that was evident when she returned to Rosyth do seem to be consistent with her having hit, and ridden over a submerging submarine.
A surfacing submarine, or one running at periscope depth, should prudently be listening for the sound of any vessel on the surface. Apart from the watch presumably also being kept on the conning tower of the other submarine, there should also have been an operator below, keeping a listening watch with the acoustic detection devices, which should have been able to pick up any noise on the surface.
Perhaps at only three knots, Wilk was not making enough noise to be heard above the noise being made by the other submarine itself.
There is, however, one recorded underwater collision between two U-boats. On 8 December 1942, while U-221 and U-254 were both submerged, attacking convoy HX-217 south of Iceland, they collided with each other. Both boats were able to surface, but U-254 was so badly damaged that she could not dive again. Shortly afterwards she was attacked by an aircraft. Some of her crew abandoned the U-boat, but only four were picked up by the U-221. The other 41 members of the crew were lost. An enquiry found that no-one had been at fault.
Here is what the Naval Historical Branch of the Ministry of Defence wrote about the Wilk incident:
"Details of ORP Wilk's patrol of 20-21 June 1940 will be held by the Public Record Office under the Class Mark ADM 199/286. The only reference made to the incident in the Naval Historical Branch's records is in the Admiralty War Diary entry for 27 June. This report states that Wilk collided with a submerged object, probably a submarine, at 0025 on 20 June when midway between Lister and Newcastle. Information had been received that a U-boat made a long signal at 16.30hrs on 20 June, about 22 miles from the position where the collision took place. These details should be corroborated by the patrol report in the Public Record Office."
Which U-boat made that long signal?
Research has identified only two U-boats that could have been in that area of the North Sea at that time in June 1940. One is U-99.
Kenneth Wynn in "U-boat Operations of the Second World War" says about U-99's patrol:
"18.6.40 Left Kiel for operations in the Atlantic. Soon after leaving a crewman reported sick, and U-99 was ordered back to Kiel to disembark him. The boat sailed again, heading for Norwegian waters. A British submarine was sighted en route but Kretschmer avoided it. He had been warned not to enter certain areas because the Scharnhorst was moving southwards along the Norwegian coast. In avoiding the British submarine, U-99 went into prohibited waters and she was spotted and attacked by an Arado floatplane from the Scharnhorst. U-99's periscope was damaged in a near miss by one of the Arado's bombs.
U-99 reached Bergen but Kretschmer decided to go for repairs to Wilhelmshaven. He reached there 25.6.40"
It would therefore have been impossible for U-99 to be 22 miles away from the position of the collision (5650N 0337E) on 20/21 June. At that time, U-99 was somewhere near the Norwegian coast. ( At the time of 19-20 June, U-99 for sure would be near Danish coast or on her way back to Kiel to disembark him) U-boats could only transmit radio messages while surfaced, and Kretschmer, who was a careful commander, would not have risked staying on the surface near a British submarine which was sighted en route, in a prohibited area, to send a "long signal".
Before explaining the significance of the 'long signal', it might be considered that the 'British submarine' seen by U-99 could have been the O-13, which would therefore have still had to be afloat during 18-19 June.
John Eade a webmaster of Royal Navy submarines, told me: "It's worth mentioning that the British minelaying in that area (463 mines) was aimed at restricting the movement of U-boats. It could be assumed that when U-99 saw a British boat, they thought it was laying mines, as Porpoise had been seen and attacked two days earlier, and had taken a known clear channel to escape the area. - [Chronology of the War at Sea, J Rohwer and G. Hummelchen]. "
The identity of the British submarine seen by Kretschmer is not known, but it may have been one of several British submarines which carried out minelaying missions in the Norwegian sector of the North Sea during 9-26 June 1940. Narwhal laid a mine barrage near Utsire on the 11th and 12th. Porpoise laid a barrage off Kristiansand on the 18th. The French submarine Rubis laid two barrages in the area of Bergen on the 9th and 26th. Tetrarch sank the tanker Samland SW of Lister at 58.12N 06.13W, on the 16th, and Clyde attacked and damaged the cruiser Gneisenau off Trondheim on the 20th.
What is a 'long signal'?
According to Peter Padfield, in "War Beneath the Sea", (p 104): ..."[Traffic analysis of German radio signals] had identified certain routine signals: a short signal made by all U-boats at 10°W after departing a French base to notify U-boat Command that they had crossed Biscay safely and were on their way to the patrol area, sighting, shadowing and weather reports, and long end-of-patrol messages indicating a boat was on its way home, could all be recognised".
In general, long signals were avoided, but they normally indicated that a U-boat was sending a message to say that she was returning to her base.
The only other U-boat that might have been in that area of the North Sea at that time, was U-122...
Several different claims have been made to account for her loss...Some claim that she was lost in the North Sea, others that she was lost near the Irish Sea, close to the Inner Hebrides, or in the eastern Atlantic.
Even the date of U-122's loss is uncertain. She was posted missing on 21 June - the same date the Wilk collision took place. (Wilk collided with an unidentified submarine at 00.25hrs on 21 June).
In his book "U-boat Fact File", Peter Sharpe says that U-122 left Kiel on 13 June, and was lost between the North Sea and the Bay of Biscay. She sent her last transmission on 21 June in position 56.03N 07.55W. Possibly sunk 23.06.40 in a depth-charge attack by RN corvette Arabis escorting Convoy OA175, with all 48 hands. (No position is given for that attack).
Sharpe also credits U-122 with sinking the British steamship Empire Conveyor on 20 June.
Lloyds recorded the Empire Conveyor as having been sunk at 56.16N, 08.10W - very close to the position in which U-122 is recorded as having sent her last message.
Kenneth Wynn, in "U-boat Operations of the Second World War" says of U-122:
"13.6.40 Left Kiel to operate in the Atlantic.
On the 20th U-122 probably (my italics) sank the SS Empire Conveyor W of the Tiree Passage, Inner Hebrides. U-122 was not heard from after the 21st and her loss is attributed to an unknown cause."
Author Paul Kemp claims that U-122 was sunk between the Bay of Biscay and the North Sea.
The highly recommended website U-boat Net, operated by Gudmundur Helgason, with whom I have had personal talks, told me that U-122 was lost off the Dutch Coast.
Unfortunately I cannot say what actually happened, or who is correct.
We have an official report which claims that 8 hours before the collision,(or after 16 hours) a U-boat was only 22 miles from the position in which Wilk said the collision occurred, and other accounts that claim U-122 was near the Irish Sea, or the North Sea.
U-122 left Kiel on 13 June, to operate in the Atlantic. It seems very unlikely that she patrolled in the North Sea for 7 days after leaving Kiel, but she might have had to return to base early, during 19-20 June because of some mechanical, or other problem. If that was the case, U-122 returning to her base, might have sent the long signal, and later could have been hit by the Wilk, as their paths crossed.
But it is difficult to determine U-122's exact position, as the several different assumptions concerning her loss attest.
Another interesting bit of information that Borowiak provides in his first volume on page 275 is that one day after the Wilk collision (19-20 or 20-21 June at midnight) at 02:00 a message was received by the Admiralty stating that the whole day British aircraft had been following a U-boat which was obviously travelling from Scotland to Germany and that it was near Wilk's patrol area! This is obviously something new as Romanowski does not say anything about it in his book…
But again the dates are confusing. If we look at the data from 19-20 June we see that one June 20th a long signal was sent by a U-boat at 16:30 near the location of the Wilk collision and on 20-21 June at 02:00 the Admiralty was informed that a U-boat was near Wilk's patrol area. So we could assume that Wilk could have hit a U-boat damaging it seriously and that the U-boat after surfacing sent a long message and was noticed by British aircraft on its way to Germany. It might also have been that the collision took place June 20th and that the U-boat was near Wilk's position then and that after the collision on the 21st the British planes spotted the U-boat and started hunting her.
But which U-boat was it? This is a big mystery. We explained above the U-122's route and its position at the time but with the new information that Borowiak provides (probably his source is S.M Piatkowski,"Kroniki Polskie Marynarki Wojennej 1918-1946" New York 1987) it is clear that this U-boat could not be other than U-122! So that means U-122 was not in Tiree Passage on 19-21 June and that she did not sink a ship there. We will not however, try to analyze U-122's route further.
We also know that naval author Pior P. Wieczorkiewicz in an article in the magazine "Mlody Tecnhik" nr 10,p 40 in 1969 was the first to put forth the theory that U-122 was rammed by Wilk.
How do we know that it was a U-boat which sent the signal on 20 June?
According to Erling Skjold, a Norwegian military communications officer, a signal could easily be identified due to its frequency, kind of transmitter and callsign. It could have been anything that used Telefunken equipment.
I had a theory of my own, that a U-boat might intentionally give a wrong position in her message.
Jerry Proc from HMCS Haida Naval Museum, Toronto commented:
"If a U-boat wanted to send a false position report, it would have to do so in plain text. (Obviously a cipher message would be pointless). In doing that, it would have been immediately obvious that is was a false transmission as no U-boat would ever want its position known to the British authorities. If a false position report was sent, then direction finding would have verified the transmission as false. With DF'ing you can't say you're in the North Sea while transmitting from the Irish Sea."
O-13's last radio message was on 13 June. Again Erling Skjold commented that it is strange for a submarine not to respond to any message during the rest of her patrol.
Different versions of O-13's loss exist.
The Royal Naval Historical Branch said that O-13 was lost in the same minefield that claimed Orzel, on 13 June 1940, around 5700N 0340E. This information is recorded in the Public Records Office under Class Mark ADM 199/1925.
The Dutch authorities say that O-13 was lost in German minefield 16B at about 5655N 03E.
That second version is perhaps more likely to be right, since the other minefield near the area was British, and E.H Vorser should have been aware, before his departure, that a British minefield was there.
In 1962 the British Admiralty admitted that British warships laid mines around 5700N 0340E in late May, and some Allied ships, including Orzel, were not informed about that minefield. Orzel could have been lost to that British minefield on 25 May 1940
O-13 was probably lost to the German minefield, which was at that time unknown to the Allies. It would have been an error of gross negligence on the part of the British to send Vorser to patrol in that area without informing him about the existence of the new British minefield before he sailed on 12 June.
In trying to avoid the British minefield, Vorser may have been unfortunate enough to fall victim to the German minefield, of which he was unaware.
The exact dates on which submarines were lost to mines are not known.
On 25 May, when Orzel was presumably lost in that area, the sound of a big explosion was heard by the British acoustic stations. On 13 June, when O-13 may have been lost, an explosion was also heard. There were other instances in the Mediterranean Sea.
The theory that O-13 was lost in collision with the Wilk, seems to be based simply on the fact that O-13 was known to be in the North Sea, and went missing some time around the date of Wilk's collision with an unknown submarine, coupled with the fact that no other potential candidate has been identified.
It has been supposed that U-122 was elsewhere.
O-13 was due to return to her base on 21 June, and it seems odd that she was still as far as 300 nautical miles from her base on 20/21 June. Of course submarines were sometimes delayed in reaching their bases, but that was a rare event, and usually the submarines informed their bases that they would be delayed due to mechanical problems, etc.
But on 19-20 June, O-13 was 300 nautical miles from the collision. That means O-13 could be near Wilk's patrol area but again Borowiak correctly mentions that allied patrol areas were precise and not near each other. At the end Borowiak in general claims that O-13 was not sunk by Wilk and that what happened that night will remain a mystery.
Can we reach a conclusion?
We have two different versions, and no one knows which is the correct one.
The answer must be found on the seabed, not only in the North Sea, but also in the Irish Sea.
It might be interesting to examine the wreck of the Empire Conveyor, the ship that U-122 probably sank, to see if it was sunk by a torpedo, or a floating mine, or due to another cause, such as an explosion in the engine room etc.
It would be even more interesting to find and examine the wrecks of U-122 and O-13.
There is no overwhelmingly convincing proof that Wilk hit either U-122 or O-13 on 20/21 June.
The possibility remains that Wilk may have hit a mine, but that cannot be proved.
Most authors don't' examine the possibility of Wilk just damaging a submarine intead of sinking it. Borowiak in a monotonic analysis states that no U-boat was lost on 20 June and therefore, Wilk hit something else. But a submarine could have been damaged and still been able to escape.
I shall leave the last words to Dr. P.C van Royen, Director of the Institute for Maritime History in the Netherlands, who based his comments on the Dutch official records in IMH, SDOC, Hr. Ms. 0-13,and also to Jak P. Mallmann Showell of U-boat Archive:
"It is still not clear how Hr.Ms. O-13 was lost. The ship, under the command of Lieutenant Commander E.H Vorser, was reported missing after 21 June 1940. It was claimed that the Polish submarine Wilk had rammed the Dutch ship on 20 June because the Polish commander believed that he was engaging a German U-boat. The Polish commander reported that this submarine was hit near to its cannon, but Hr.Ms O-13 had no such armament. More likely, the Dutch ship has been sunk 13 June 1940 in a German minefield positioned at 56'55N 03E."
"Thank you very much for your letter of 13 July. Regretfully there is no one in the archive who can deal with English language letters and I am only here for a few weeks each year. So please excuse the delay in answering.
The archive cannot afford to employ staff and relies entirely on volunteers and contributions from visitors.
Your most interesting account of the Wilk Case makes fascinating reading. I shall make one copy to take home so that I can study in detail later. Horst Bredow is absent at the moment, but I am sure he will be delighted to add it to the archive's collection. Thank you very much for sending us a copy.
Jak P. Mallmann Showell