Wilk's mines draw a submarine hunt months after its departure

A mine laid by Wilk sank a German fishing vessel on 7 December 1939, after the submarine had reached Britain and resumed other operations. The loss provoked a large German search for a Polish submarine that was no longer there. A minefield leaves its opponent uncertain about when the weapons were laid and whether the submarine remains nearby. That uncertainty can consume search resources long after the boat has departed. A proposed modern extension is for submarines to lay systems that release torpedoes, preserving a threat without remaining in the area.