Original Documents from the National Archives, Kew : Decyphered W/T messages

     Tracking German Navy units was one of the main efforts of Room 40. A large amount of the W/T
     traffic from, to and between submarines in North Sea and Atlantic was decyphered.



   ADM 137/4152 - U-boat history sheets comp. By Lt.Cdr. Tiarks :

     U 19, 1914-1918, 19 pages

     U 20, 1914-1916, 17 pages
       The U-boat, which sunk the Lusitania on May 7, 1915. Sheet No. 4 shows the exact
       position of U 20 off the Irish South Coast, while the LUSITANIA is arriving from the West.
      

     U 21, 1914-1918, 10 pages
       U-21 arrived the 13th May 1915 after a long voyage from the North Sea in the Austrian
       mediterranean base of Cattaro. On May 19th a german W/T message from Constantinople arrived :
       "Very urgent. Please pass on to U.21 at Cattaro, favorable objective for first attack,
       battleships lying at anchor in square V441."
       U-21 left Cattaro the 20th May and sank the pre-dreadnoughts H.M.S. TRIUMPH and H.M.S. MAJESTIC
       the 25th and 27th May 1916 at the Dardanelles.
      
     U 22, 1914-1918, 17 pages



   ADM 137/3912 - Original History Sheets UA-U40 :

     U 35, Jan 1915 - Dec 1917, 14 pages
       The most "successfull" German U-boat sank 1915 - 1917 over 200 ships
       with more than 500.000 BRT, most of it in the Mediterranean
       under its Commander Arnauld de la Periere.



   ADM 137/4155 - U-boat history sheets comp. By Lt.Cdr. Tiarks :

     U 92, Oct 1917 - Sep 1918, 6 pages
       Cruise Jan 1918 : Atlantic
       Cruise Feb 1918 - Mar 1918 : Atlantic
       Cruise Apr 1918 - May 1918 : Atlantic
       Cruise Jun 1918 - Jul 1918 : Atlantic
       Cruise Sep 1918 : North Sea, sunk

     U 151, 1917 - 1918, 4 pages
       Cruise Sep 1917 - Dec 1917 : West Africa, Cap Verde Is.
       Cruise Apr 1918 - Jul 1918 : U.S. East Coast

     U 152, 1918, 2 pages
       Cruise Dec 1917 - Apr 1918 : Canary Is., Azores

     U 153, 1917 - 1918, 5 pages
       Cruise Feb 1918 - Jun 1918 : Canary Is., Azores

     U 154, 1918, 4 pages
       Cruise Feb 1918 - May 1918 : Liberia, West Africa, Canary Is., Azores, sunk

     U 155, 1917 - 1918, 3 pages
       the former mercantile submarine U-DEUTSCHLAND
       Cruise Jan 1918 - May 1918 : West Africa, Azores

     U 156, 1917 - 1918, 6 pages
       Cruise Oct 1917 : abandoned
       Cruise Nov 1917 - Mar 1918 : Azores, Canary
       Cruise Jun 1918 - Sep 1918 : U.S. East Coast, sunk

     U 157, 1918, 2 pages
       Cruise Dec 1917 - Apr 1918 : Canary Is., Azores
       Cruise Jul 1918 - Nov 1918 : Azores, Madeira