Around the southern coast of Banks Peninsula, Holmbank's course was calculated to pass within 2 miles of the Akaroa light.
The light was obscured in fog, and a current brought the vessel very close to the shore, unknown to the crew.
By the time the Akaroa light would have been in range, it was obscured by high ground, the ship being so close to the shore.
At 8.22pm on the night of 19 September, Holmbank ran aground at full speed, striking Whale Rock, 200 m from the cliffs at the northern entrance to Piraki Bay.
It is considered a dangerous dive site due to strong tidal set and heavy swell.