An ODT photographer saw Pacific Explorer enter Otago Harbour while Taiaroa Head was enveloped in thick fog.
He said the vessel appeared to feel its way through the fog, sounding its fog horn.
Port Otago chief executive Kevin Winders said Pacific Explorer sailed past Timaru because of the weather there and arrived in Port Chalmers about 8.30am.
It was delayed for about an hour as it cleared through the fog sufficiently.
Both vessels were having to make choices based around the weather and adapted to the conditions, he said.
Various ports had different wind limits and constraints about ships coming in and out.
Mr Winders said wind had been forecast around the time each ship was expected to depart, which was being monitored carefully.
"If the wind exceeds limits, safety is always a priority so they won’t leave the port."
