The timing schedule was upset by the tide, which was driven in-shore by a strong north-westerly wind, with water levels running 30 minutes earlier than normal.
With a strong north or north-westerly wind both the rate and duration of the southwest-going ebb are increased, and the southwest-going ebb may begin quarter of an hour earlier.
The ship was seen by the lighthouse keeper at 4:30 p.m. on a north-westerly bearing about 29 km (18 mi) off the coast of the island, heading north-east.