A well-respected teacher found guilty of abusing vulnerable boys betrayed their trust, a court was told.
Graham Stride was found guilty of 15 charges of indecent assault involving six boys and two of attempted indecent assault involving a seventh boy.
The offences took place between 1982 and February 2004.
Stride, 50, of Elson, Gosport, Hants, who had denied all of the charges, was found not guilty of two charges of indecent assault of an eighth boy.
On Thursday, it took a jury of five men and six women seven hours to find Stride guilty.
Earlier, Janice Brennan QC, prosecuting, had told the court Stride concocted excuses to be alone with the young boys so he could abuse them.
She added that a school had been told of his behaviour around 1986 but did not inform the police.
Miss Brennan said: "Instead of the incidents being reported to the police, it appears the education authority preferred there to be no scene, no trouble at
all."
An earlier prosecution in 1993 against him was also dropped because the parents of the alleged victim decided against their son giving evidence in court.
Sister Mary Jo Martin, director of schools for the Catholic Diocese of Portsmouth, which took Stride on as a member of staff two years ago, said it had not been made aware of any allegation against him until his arrest this year.
John Wakeling, head of education for Hampshire County Council, said that it would review its procedures in light of Stride's conviction, adding stringent measures were in place to screen new members of staff.
Stride was ordered to sign on the sex offenders' register and released on conditional bail until his sentencing at Portsmouth Crown Court on 14 January.