Last year his frustration reached tipping point and Mrs Derecourt said there was a lot of abuse flying down by the river that day.
Mr Hughes and Mr Ashton left the scene and returned when they believed Wilson would have left but he was there waiting for them.
He first approached with a knife but that was dislodged in the struggle, Mrs Derecourt said.
But it was not the end of the attack.
Wilson jumped into his car and pursued Mr Hughes, who fled towards the boat ramp.
Mrs Derecourt said the car caught his leg and knocked him over and Wilson continued to pin him against the side of the boat ramp.
"His leg was just hanging by skin and there was blood everywhere," she said.
To compound Mr Hughes' issues, the ambulance could not go down to the river before the police armed offenders squad had determined the area was safe.
Eventually he was flown to Middlemore Hospital with life-threatening injuries.
Mr Hughes' mother said she was told the "best-case scenario" would be that he lost his leg.
But a plastic surgeon spent hours on the mangled limb and was able to save it.
Mr Hughes was in hospital for more than three months and has been on crutches since, unable to put weight on the heel of the injured leg.
"He might never be able to," his mum said.
Wilson will be sentenced in May and the Crown will drop charges of assault with a knife and possession of a firearm at that hearing.
"It's crazy. All this over a whitebaiting stand," said Mrs Derecourt.