German Submarine Warfare 1914-1918 in the Eyes - British Naval ...

Table 15: Ocean-Going U-boats available Sep. 1916 - Sep. 1917, North
Sea and Atlantic 58
100
90
80
70
60
50
40
30
20
10%
10
1916
Sep
26%
Oct
Ocean-going uboats avail. per day
Percentage used on merchant war
22% 20%
Nov
Dec
24%
1917
Jan
29%
Feb
58 Numbers based on: NA, HW 7/3; Spindler, Handelskrieg; and Bendler, UB- und UC-Boote.
59 Birnbaum, Peace Moves and U-boat Warfare, pp. 201+202.
xxxii
33%
Mar
36%
Apr
33%
May
38%
Jun
35%
Jul
38%
35%
The number of boats in service grew from fifty-eight in October, 1916 to
ninety-two in September, 1917. On an average daily basis, around fifteen U-boats
operated in the restricted period and thirty boats were in the unrestricted war. No
boats were held in reserve to support the High Seas Fleet in 1917 when the
unrestricted campaign commenced. In 1916, around 25% of the available boats
were on cruise, in 1917 used boats jumped to more than 35%.
Aug
Why restricted submarine war in October 1916?
High Seas Fleet commanders opposed restricted submarine measures in the
summer of 1916. By early autumn, Captain Karl Bartenbach, chief of the Flanders
based submarine flotillas, pressed for its resumption. From the middle of
September the Flanders and High Seas Fleet submarine force resumed the
commercial war in accordance with the rules of cruiser warfare. 59 This worked well
for the next four and a half months. There were no new, distracting diplomatic
problems and the tempo of merchant vessel sinkings around the British Isles was
high. This was proof that restricted submarine warfare was tactically and
strategically successful.
Sep
50%
45%
40%
35%
30%
25%
20%
15%
10%
5%
0%