The Prince of Whales boat with 24 tourists on board was just coming back from its evening run on Friday, when the captain heard a mayday call from another vessel over the radio.
"It had a family on board that suffered an engine fire," said Paulo O'Connor, who runs the company.
"We brought the [rescue] dingy over to our boat and brought the family over," said O'Connor.
O'Connor says the original location given by the distress call was incorrect, but the captain found the boat quickly using GPS and charts.
Staff helped to calm and entertain the young children, who appeared to be about 3 and 5 years old, O'Connor says.
No one was hurt and the fire was completely put out. The family was then picked up by a coast guard hovercraft and taken to Thunderbird Marina.
"We call that part of the day the adventure crossing anyway, so our passengers were up for the challenge," O'Connor quipped.
The whale watching tour continued on to its final destination.
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