German submarine U-60 (1939)
Summary of raiding History

Date
Ship
Nationality
Tonnage (GRT)
Fate
19 December 1939
City of Kobe
United Kingdom
4,373
Sunk (Mine)
13 August 1940
Nils Gorthon
Sweden
1,787
Sunk
31 August 1940
Volendam
Netherlands
15,434
Damaged
3 September 1940
Ulva
United Kingdom
1,401
Sunk

Question: How destructive is U-60?
Answer: U-60 sank three ships for a total of 7,561 GRT and damaged another one of 15,434 GRT.