Hello Jan-Olof,

According to Polish sources on 20.VI.1940 at 0:25 [after midnight hence it was already 20.VI not 19.VI nor 21.VI!!] in position 56°50’ N / 03°37’ E, lt Romanowski spotted strange object in the water [around 300 m]. He decided to ram it. In the colision, Wilk was heavily damaged. There are several possibilities of the results of the ramming:
(1) Wilk rammed Dutch submarine O-13, which is doubtfull since it is belived that O-13 sunk on mines on 13.VI.1940 in position 56º55' N / 03º40' E
(2) Wilk rammed German submarine U-122 which went missing in North Sea around this period
(3) Wilk hit a mine which is a bit strange, since I never heard of any sub heaving damaged only stern, afer running on a mine
(4) Wilk run on rocks at the Dogger Bank shallow [Great Fisher?!]

Personally I do think that Wilk hit the rock, since on that patrol ship was commanded by unexperienced officers [Karnicki, Romanowski, Koziolkowski - it was their first independent patrol] any due to faulty navigation, ship run on rocks. I belive that Romanowski version was only cover-up for his incompetence.

You can read more in article written by my Greek friend Militades Varvounis, at my webpage:
[www.polishnavy.pl]

Best wishes,
abz