At 0400, with the approach of dawn and improving visibility, the general shape of the ships became clear, but it was still not possible to see enough detail to determine exactly whose ships they were. At 0412, Murphy ordered the signalman to use the signal light to send an ID signal. When the response was unintelligible, the sub crash-dived. When there was no attack, the sub was brought to periscope depth, where damage to the cruiser s bow was easily visible.