This is september '39 just after the outbreak of the war. This region of the Irish/Celtic sea seems to make the trip worth while. Plenty of small freighters for the deck gun, but also with patience enough large merchants. Also plenty of time submerged at 2kts/silent using your hydrophone makes a big difference I find, if you don't do so already.
[Log Entry 0]
Type=0
EntryText=Patrol 1|U-Straylight, 2nd Flotilla|Left at: September 1, 1939, 13:57|From: Wilhelmshaven|Mission Orders: Patrol grid BE31
Date=19390901
Time=1357
Categ=0
[Log Entry 1]
Type=0
EntryText=Ship sunk!|Grid BF 26|Large Merchant, 11539 tons
EntryTitle=September 5, 1939, 07:08
Date=19390905
Time=708
Categ=0
[Log Entry 2]
Type=0
EntryText=Ship sunk!|Grid BF 26|Passenger/Cargo, 2045 tons
EntryTitle=September 6, 1939, 01:17
Date=19390906
Time=117
Categ=0
[Log Entry 3]
Type=0
EntryText=Ship sunk!|Grid BF 26|Large Merchant, 11535 tons
EntryTitle=September 6, 1939, 20:17
Date=19390906
Time=2017
Categ=0
[Log Entry 4]
Type=0
EntryText=Ship sunk!|Grid BF 13|Small Merchant, 1818 tons
EntryTitle=September 9, 1939, 05:41
Date=19390909
Time=541
Categ=0
[Log Entry 5]
Type=0
EntryText=Ship sunk!|Grid BF 13|Whale Factory Ship, 10756 tons
EntryTitle=September 9, 1939, 19:35
Date=19390909
Time=1935
Categ=0
[Log Entry 6]
Type=0
EntryText=Ship sunk!|Grid BF 13|Small Freighter, 2212 tons
EntryTitle=September 9, 1939, 22:27
Date=19390909
Time=2227
Categ=0
[Log Entry 7]
Type=0
EntryText=Ship sunk!|Grid BF 14|Medium Cargo, 5134 tons
EntryTitle=September 11, 1939, 03:52
Date=19390911
Time=352
Categ=0
[Log Entry 8]
Type=0
EntryText=Ship sunk!|Grid BE 31|Medium Cargo, 5177 tons
EntryTitle=September 12, 1939, 14:33
Date=19390912
Time=1433
Categ=0
[Log Entry 9]
Type=0
EntryText=Ship sunk!|Grid BF 12|Modern Medium Tanker, 10159 tons
EntryTitle=September 14, 1939, 02:32
Date=19390914
Time=232
Categ=0
[Log Entry 10]
Type=0
EntryText=Ship sunk!|Grid BF 12|Small Merchant, 2420 tons
EntryTitle=September 14, 1939, 02:39
Date=19390914
Time=239
Categ=0
[Log Entry 11]
Type=0
EntryText=Aircraft destroyed!|Grid BF 24|Hurricane Mk IIC
EntryTitle=September 14, 1939, 16:59
Date=19390914
Time=1659
Categ=0
[Log Entry 12]
Type=0
EntryText=Aircraft destroyed!|Grid BF 24|Hurricane Mk IIC
EntryTitle=September 14, 1939, 18:02
Date=19390914
Time=1802
Categ=0
[Log Entry 13]
Type=0
EntryText=Ship sunk!|Grid BF 24|Small Freighter, 1667 tons
EntryTitle=September 14, 1939, 18:20
Date=19390914
Time=1820
Categ=0
[Log Entry 14]
Type=0
EntryText=Ship sunk!|Grid BF 24|Small Freighter, 1668 tons
EntryTitle=September 14, 1939, 18:40
Date=19390914
Time=1840
Categ=0
[Log Entry 15]
Type=0
EntryText=Ship sunk!|Grid BF 35|Large Merchant, 11461 tons
EntryTitle=September 16, 1939, 04:10
Date=19390916
Time=410
Categ=0
Further to this I am currently in BF 15 on my second tour facing the largest convoy I have ever seen in GWX, large modern tankers/large merchants/whale tankers/ etc. Nice, but there are hurricane winds and sea state so surface attack is impossible, can't use the deck gun either of course. Submerged attack the only option. However being in a VIIB with limited torpedos and only one yes 1! black swan escort to face, the frustration is incredible. Oh for a IXb.............