Monarch Cruises owner Neil Harraway said the boat was on its way to Wellers Rock on the Otago Peninsula, to pick up passengers for a 1.30pm cruise.
However, as it neared the Ravensdown wharf in Ravensbourne, it had to make way for the Maea, an LPG vessel, which was headed for the LPG terminal in Dunedin.
Maritime rules say the channel must be clear of all other vessels when a fuel boat is in the harbour.
"They [the Monarch’s skipper] pulled out of the channel to let the tanker go past and they just drifted with the wind into a shallower spot where there is soft mud," Mr Harraway said.
The boat would remain grounded near a man-made dolphin — a structure used to secure ships at the Ravensdown wharf — until the tide had risen high enough for it to be refloated.
"There’s no damage to the boat. It’s just sitting there on the soft mud."
He said the Monarch only missed the 1.30pm tour, and its passengers were rescheduled to travel on another tour.
