Did U boats change tactics after Q ships were introduced?

[Simon Cains]

Is there any evidence that the German navy knew about Q ships ?  If so, that would be a very reasonable excuse to go to a "sink on sight" policy.  It seemed barbarous to the allies, but Q-ships "punished" the more civilised U-boat captains who would stop a ship and allow the crew to take to lifeboats.  However I can't see any evidence that things actually happened that way.  The germans did not seem to say that they went to unrestricted warfare due to Q-ships.  Wikipedia claims that "The use of Q-ships contributed to the abandonment of cruiser rules restricting attacks on unarmed merchant ships and to the shift to unrestricted submarine warfare in the 20th century.[1]" but only points to a broken link, which doesn't say that at all. http://navymuseum.co.nz/q-ships/    Thanks very much.

[KizmeRD]

Q-Ships enjoyed some early successes after they were first introduced in the summer of 1915, but by the end of 1917 they were largely ineffectual. Therefore one might reasonably conclude that U-boat commanders had indeed developed tactics to counter them, either by determining not to attack lone merchantmen displaying uncharacteristic patterns of behaviour, or simply by torpedoing them whilst still submerged. Certainly after the notorious Baralong incident in August 1915, this became pretty much standard practice. The Q-Ship relied on deception to be effective, and once the cat was out of the bag, U-boat commanders were no longer easily fooled.

MB

Edited 12 August , 2023 by KizmeRD

[Felix C]

Submarine commander memoirs mention how suspicious vessels were approached or avoided. Approached as in surfacing with the sun in the eyes of any hidden gunners on the target and other submarine favorable situations. Or approaching from astern and shelling from a distance until the vessel was well down. Descriptions of Qships encountered and survived were circulated. 

Edited 12 August , 2023 by Felix C

[KizmeRD]

As Felix has stated, there are plenty of mentions in former U-boat commanders memoirs relating to how they viewed Q-ships, and how they responded to them, but the basic statistics are telling…

In 1915 (part year only) 7 U-boats were sunk by Q-ships (without loss)

In 1916 only 3 U-boats were sunk by Q-ships, and 5 Q-ships were lost.

In 1917 there were 4 U-boats sunk by Q-ships, and 24 Q-ships were lost.

And in 1918 no U-boats were lost (indisputably lost) due to Q-ships, but 7 Q-ships got sunk.

MB

Edited 12 August , 2023 by KizmeRD

[Simon Cains]

3 hours ago, KizmeRD said:

As Felix has stated, there are plenty of mentions in former U-boat commanders memoirs relating to how they viewed Q-ships, and how they responded to them, but the basic statistics are telling…

In 1916 (part year only) 7 U-boats were sunk by Q-ships (without loss)

In 1916 only 3 U-boats were sunk by Q-ships, and 5 Q-ships were lost.

In 1917 there were 4 U-boats sunk by Q-ships, and 24 Q-ships were lost.

And in 1918 no U-boats were lost (indisputably lost) due to Q-ships, but 7 Q-ships got sunk.

MB

Thanks, I couldn't find anything definite from Dr Google like that.  Is there a good online place to find that kind of detail ?  ( Apart from the GWF of course ...). 

I wasn't sure how many U-boats survived an encounter with a Q-ship, or if the Q ships took prisoners who let the secret out.

[Michael Lowrey]

The latest numbers on U-boat losses to Q-ship:

1915: Four (U 36, UB 4, U 27, U 41) plus, if you want to include it, two to trawler plus submarine combinations (U 40 and U 23)

1916: Two (U 68, UB 19)

1917: Four (UB 37, U 83, UC 18, UC 29)

Note that the nature of the sinkings changes. The 1915 sinkings are very clean, with the Q-ships not taking any damage. Though four U-boats were sunk by Q-ships in 1917, in all cases, the Q-ship also took substantial damage. The Q-ships that sank U 83 (Farnborough) and UC 29 (Pargust) both took torpedo hits. The Flanders-based UB 37 (Penshurst and UC 18 (Lady Olive) both inflicted significant gun hits on their their Q-ship targets before the decoys would return fire. Indeed, Lady Olive also sank as a result of the damage it received from UC 18.

[Borden Battery]

Michael Lowery's website, along with Gudmundur Helgason, is the definitive website on this topic.  Borden Battery

*** U-Boat - U-boat War in World War One

This primary website contains detailed information on the German U-Boat from both the Great War and the Second World War.  The site also contains a discussion forum and a good source of referenced material and articles including some new maps.  While the site is primarily Second World War, there is a growing commitment to the Great War.  Statistics indicate apparently in WWI a total of 375 U boats sank 6,596 merchant ships, a total of 12,800,000 tons.  The site is operated from Iceland by Gudmundur Helgason with a detailed database being developed by Michael Lowrey. [CEF Study Group – Sept 2022]

http://www.uboat.net/wwi/

[KizmeRD]

4 hours ago, Michael Lowrey said:

The latest numbers on U-boat losses to Q-ship:

1915: Four (U 36, UB 4, U 27, U 41) plus, if you want to include it, two to trawler plus submarine combinations (U 40 and U 23)

1916: Two (U 68, UB 19)

1917: Four (UB 37, U 83, UC 18, UC 29)

Thank you for the update Michael.
The problem is that there were always more U-boats claimed to have been sunk than actually were sunk. Much depends on when and where you draw your data from. 

MB