A former rowing coach now behind bars for rape was considered a family friend of the victim.
The 60-year-old, whose identity can't be revealed, attacked a woman in her tent at a school regatta at Lake Barrington in March last year, while children including her teenage son slept nearby.
A Supreme Court jury last month returned a unanimous guilty verdict on rape and indecent assault charges.
He was gaoled on Wednesday for four years but could be paroled in two.
He'll go on the sex offenders register for three years on release.