Eleven days later she closed two freighters under escort of two destroyers off the western coast of Yap Island and let go five torpedoes at the largest merchantman. The first hit stopped the target dead in the water and a second torpedo tore off the port quarter capsized the 5873-ton cargo ship "Atlantic Maru". Two destroyers came down the torpedo tracks to hover over "Picuda" and she was shaken by 26 exploding depth charges before she escaped. With only one torpedo worth firing she returned to Midway Island on 5 April. Upon completion of her refit, she took aboard student officers and men for indoctrination training exercises off Midway, from 28 to 30 April. Three days later she formed a wolf-pack with submarines and .