WW2 German U-Boat Clock

A World War II German U-Boat 8 Day Clock. Good time keeper, with 2 Keys. The clock is housed in a metal box, for fixing to a bulkhead. With German Eagle above an M and numbered 15069. No makers name visible. My father was in the Navy and he was given it at the end of the war when the U-boats were decomissioned when it was moored in a Northern Ireland dock. It has been in my family since the end of WW2.