The third merchant vessel that U-37 sank on her tenth patrol was the British ship Brandenburg , on 10 February .
The next day , U-37 sank two British ships , Courland and Estrellano .
The third merchant vessel that U-37 sank on U-37 's tenth patrol was British British ship Brandenburg , on 10 February .
The next day , U-37 sank two British ships , Courland and Estrellano .