That evening "Harder" sighted two enemy destroyers patrolling the narrowest part of the passage, just a few miles from Tawi-Tawi. After submerging, she made an undetected approach and at fired four torpedoes at the overlapping targets. The second and third torpedoes blasted "Tanikaze"; she sank almost immediately, her boilers erupting with a terrific explosion. The fourth shot hit the second ship, which exploded with a blinding flash. Within minutes "Harder" surfaced to survey the results, but both ships had disappeared. Soon afterward, she underwent the inevitable depth charge attack by enemy planes, then she set course for a point south of Tawi-Tawi to reconnoiter.