Original Documents from the National Archives, Kew : Analysis

     The number of available and future German submarines was estimated regularly.
     Around 370 German submarines were in service from 1914 - 1918, around 200 of them
     were lost with 5132 men dead and missing.

     The sinking of merchant ships was analyzed in detail. The world merchant tonnage
     in July 1914 had been 48 Mio. BRT; 19 Mio. BRT of it were British : 8,587 steamer and
     657 sailing vessels. More than 2,000 British merchant ships with 6.6 Mio. BRT and
     over 3,000 Allied and Neutral ships with 4.4 Mio BRT were sunk by german submarines
     in World War I. British human losses alone were over 13,000 killed.

     Strategy and tactics to fight the German submarines were discussed on all political
     and military levels : from the War Cabinett to the First Lords of the Admiralty. Finally
     the introduction of the convoy-system in the first half of 1917 overcame the menace.



   ADM 137/3870 - Specifications, administration and personnel of German submarines :

     Jan 1915 : Estimation of available submarines and future preview, 3 pages

     Jul 1915 : Estimation of available submarines and future preview, 1 page

     Dec 1916 : Estimation of available submarines and future preview, 2 pages

     Jun 1917 : Estimation of available submarines and future preview, 4 pages

     Apr 1918 : Estimation of available submarines and future preview, 2 pages



   ADM 137/3866 - Extracts from German secret instructions for war on commerce :

     Submarine results, Feb 1917, signed Bauer, 26 March 1917, 2 pages

     Summary of Submarine successes, Feb - May 1917, signed Michelsen, 21 July 1917, 2 pages



   ADM 137/4137 - Home Waters, Ships attacked 16 - 23 March 1917 :

     Alnwick Castle, 19.03.1917, 8 pages



   ADM 137/3129 - British Vessels lost, Aug 1914 - Jul 1917 :

     British Vessels, 3 pages

   ADM 137/4814 - British Vessels lost, Aug 1917 - Nov 1918 :

     British Vessels, 7 pages

   ADM 137/4817 - Foreign Vessels Sunk or Damaged by the Enemy :

     Allied and Neutral Ships Sunk or Damaged 1914 - 1918, 8 pages



   ADM 116/3421 - Unrestricted Sumarine Warfare [ before the introduction of convoy ], original version :

     Oct / Nov 1916 : no answer to the submarine problem, 6 pages

     The needle in the hay stack : destroyers search submarines, 10 pages

     Feb 1917 : facts of submarine warfare, 5 pages

     Feb 1917 : 540.000 BRT sunk, 1 page

     Mar 1917 : 575.000 BRT sunk. The situation get out of hands - defeat in sight, 3 pages

     Apr 1917 : 420.000 BRT in the first two weeks - "... building up reserves of foodstuffs while the shipping still existed ...", 3 pages