O’Callaghan blasted officials and claimed they had “driven out” the High-Performance Director, Morten Espersen.
Espersen (65) resigned in January - five months after guiding Ireland to a first Olympic medal in rowing.
Paul and Gary O’Donovan won silver in the lightweight double and the women’s lightweight double of Claire Lamb and Sinead Lynch also reached an A Final in Rio de Janeiro.
O’Callaghan likened the circumstances behind the Dane’s controversial exit to the stand-off between the Irish Amateur Boxing Association and their HP Director Billy Walsh in 2015
And speaking yesterday, O’Callaghan’s anger had still to dissipate. “I am disappointed, like a lot of people, that Morten has resigned.
“I would know him fairly well and what he has achieved for Irish rowing was incredible.
“All the plans were in place for the next four-year cycle in terms of coaches and programmes and now that he has gone I’m worried about what the future holds,” Callaghan admitted.
O’Callaghan had two stints as national team manager (1999-2002 and 2005 to 2007) overseeing 13 world championships success in his terms.
He claimed that cracks had developed between Rowing Ireland’s hierarchy and Espersen over the past two years.
“Morten came back from the Olympics, and in the public view, they all came back as heroes. In his subsequent meeting with the board, you would have expected him to be offered a four-year contract. But my understanding is that he was offered a one-year contract, less pay, and a change of title and he was going to have to work with a sub-committee. That left him in a very difficult position and he did not have much of an option but to quit.
“I get annoyed talking about it. This is history repeating itself. We had the same scenario with Harald Jahrling about 10 years ago.”
He continued: “At the agm on Sunday I compared the situation to what happened with boxing and how Billy Walsh was treated there before being forced to leave for a job in America.
“I don’t want rowing to go down that route. I have a strong opinion, I am not a shrinking violet and I voiced those opinions at the agm.”
Rowing Ireland’s outgoing president Con Cronin rejected the allegations made by Mr O’Callaghan at the Garda Boat Club in Islandbridge.
And O’Callaghan conceded there was little support from the floor following his address.
“No there wasn’t (backing from delegates). Morten was at the meeting also and at no stage was he asked to say a word. He was never invited to speak at the meeting which I found very strange given all that he achieved in his time here.
“Hopefully the upheaval created from all of this wouldn’t damage Irish rowing’s prospects at an international level. But one thing I can say for certain is that we wouldn’t get as good a high performance director as Morten again.
“Prior to him arriving the only thing we in Irish rowing were short was an Olympic medal - he promised to deliver one and achieved that in his first Olympic cycle with the team.
“He has left a brilliant legacy. We have five world-class athletes, some great development people coming through and some top class Irish coaches. But the frustrating thing is, as before, every time we have success in Irish rowing, we have disruption.”