Mr Strachan was also taken to Dunedin Hospital for a "routine check" following the incident and he was "fine".
When asked if his confidence had been affected, he said: "Yes it has, naturally, whether I'm 21 or 91."
He was more concerned for the junior rowers who were in the boat.
He had spoken to many of those involved and they had given their support, he said. He was yet to speak to the most seriously injured boy, a 12-year-old.
The boy was transferred to Christchurch Hospital for specialist care yesterday.
A Canterbury District Health Board spokeswoman said he was in a comfortable condition in a children's ward at the hospital.
The boy, who has represented Otago at age-grade level in other sports, will require specialist surgery, which could include bone grafts.
Otago Boys' High School rector Clive Rennie said no-one involved in the incident was attributing blame and there was a lot of support for Mr Strachan.
"They [the boys] are really supportive and so are the parents," he said.
"There's an acceptance that this was an accident."
The school had offered in-school and out-of-school support to the year 9 pupils involved and to senior pupils who had come to their aid.
"We had a meeting today with all the boys," Mr Rennie said.
"They are pretty good. It will take the boys a day or two to work through it, particularly those who were close to it, but I'm satisfied at the moment that we have got everything in check."
A Maritime New Zealand spokeswoman said an investigation into the incident was at the inquiry stage, and it was too early to speculate when it would be completed.
"We need to find out what's happened first," she said.
Another boy remained in Dunedin Hospital yesterday for observation, while the third was discharged on Sunday.
Mr Strachan has been involved in rowing for seven decades, and 70 of his rowers have represented New Zealand, among them 2012 Olympic gold medallist Hamish Bond.
He said he hoped to return to coaching but it was in the hands of the school.
"I intend to, if the school still wants me, but there's always a cause and effect," he said.
He could not comment on the specifics of the incident as an investigation was ongoing and he would have to wait and see if "it's considered my fault or a freak accident".
The incident comes as Maritime New Zealand marks the inaugural Safer Boating Week, from October 17-24, to raise awareness of safe behaviour on the water.