1939 attack diagrams.
Attack diagrams do not show the number of ships sunk in 1939, they give the information on the number of attacks performed by U-boats in different patrol areas. For example, according to the Convoy attacks diagram in 1939 U-Boats engaged 18 convoys, either of which could cause sinking of several ships.
The diagrams give us information on the shipping traffic intensity in different patrol areas. The information is not 100% accurate and I'll check it when I'll have time. nevertheless, it provides an overview of the U-boats patrols statistic in 1939.
On the basis of the abovementioned diagrams the following conclusions can be made:
1. High intensity of single ship traffic (90 vs 18 convoys) characterize the 1939 year.
2. The best areas have been south of Ireland (27,8%) and North Atlantic (to the west of Ireland - 33,3%).
3. The high percentage of traffic in the North Sea is due to the fact that the North Sea was the main operational area of type II U-boats, and type VII, IX U-boats had to pass the North Sea on the way to their Patrol areas.
4. The Bay of Biscay also turned out to be rich hunting "grounds", U-boats had met there 13,3% of single ships and 16,7% of convoys.
In the next post I'll publish the statistic for the 1940 year and we shall compare the results.