The ships sighted by "Tambor" were the four cruisers and two destroyers Yamamoto had sent to bomb Midway. At 02:55 these ships received Yamamoto's order to pull back and changed course. At about the same time as the course change, "Tambor" was sighted, and to avoid a submarine attack and hit into each other, causing serious damage to "Mogami"s bow. The less severely damaged "Mikuma" slowed to . This was the most damage any of the 18 submarines deployed for the battle achieved. Only at 04:12 did the sky brighten enough for Murphy to be certain the ships were Japanese, by which time staying surfaced was hazardous, and he dived to approach for an attack. The attack was unsuccessful, and at around 06:00 he finally reported two westbound "Mogami"-class cruisers.