He said he hoped to hold Haward there until police arrived.
But a jury didn't believe the man's story that he didn't intend to injure Haward and was only trying to detain him. He was found guilty of the charge following a trial in the Wellington District Court last year.
Sensible Sentencing Trust child abuse spokesman Scott Guthrie initially joined forces with the man to help him appeal his conviction, but today told the Herald it became clear that the man did not have a defence.
"It became apparent later that it wasn't just a self-defence thing, it was actually quite a violent attack on the offender," Guthrie said.
"You've got a stepfather that's defending a girl that's just been raped, and then you've got the aspect of how far do you go?
"We still stand by that everybody's got the right to defend their family and their property, but within the limits of the law."
Guthrie said the case was "a bit of a tragic story".
The stepfather took his case to the Court of Appeal saying the Evidence Act had been breached during the trial.
The relevant section of the act states the "fact-finder" should not be invited to infer guilt from a defendant's silence before trial, meaning that if a defendant does not disclose a defence before trial this doesn't mean they are guilty.
The man's lawyer said this breach came about because the prosecutor attacked his credibility by pointing out inconsistencies between his defence at trial, and what he'd told the arresting officer at the time.
The case for the Crown was very strong.
He told the officer he assaulted Haward because of the rape, and made no mention of trying to detain him. He later said during the trial he was just "being smart to the cops" because he was angry at their inaction.
The Court of Appeal found the prosecutor did not breach the act, saying in its report "she did no more than challenge [the man's] credibility".
"The challenge ... was presented in a measured and dispassionate manner and did not involve an invitation to the jury to infer [the man] was guilty because he had not previously disclosed that his intention was simply to restrain Mr Haward until the police arrived."
The Court of Appeal did find the judge breached the act by failing to direct the jury not to draw an inference of guilt based on the man's silence before trial, but the breach was not enough to cause a miscarriage of justice.
"The case for the Crown was very strong ... the evidence against [the man] was consistent and weighed heavily against his case."
The court dismissed the man's appeal.