In the second half, the team played with speed, accuracy and supreme confidence running in five long-range tries, adding one more from close in and never really having their own line threatened.
Captain Kaipo Brown, who leads the team from the blindside flank, puts the performance in this match, and the big wins which have come over recent weeks, down to the preparation and the planning.
"All of us in this team have been prepping for maybe a year now. We have created a real bond between us and we can't have it any other way.
"We knew coming into this tournament that we couldn't have any piggy backs. We go out there to die for each other. It's like a big family."
Brown, a product of Rotorua Boys High School, thinks that much of the team's success has to do with their humility.
"Most of us, we came out of school, we didn't make these flash teams that all these other boys made. And that's what gave us this work ethic."
In such a one-sided result as this, identifying individual stars is not easy.
But a powerful scrum and forward effort allowed the midfield and outside backs to run with aplomb.
Harbour had no answer to the scything midfielders Jayjay Suemai and Lalomilo Lalomilo.
Another high-school player rejected by his home province of Auckland, Lalomilo was a revelation. He scored two tries and when he had the ball in hand, Harbour must have wanted to flash the warning lights.
On the outsides, wingers Emoni Nawara and Bartje Wierenga always presented a threat and both were rewarded with a try.
Kaleb Trask scored two tries from fullback and kicked six conversions before being subbed with the match well and truly won midway through the second half.
Coach Mike Rogers, in his fourth year with the under-19s, has through a combination of classy recruiting and high-quality mentoring taken the team from 13th to at least second in the Jock Hobbs Tournament inside four years.
He admitted to some worries when the gap had closed to two points, but was delighted that the side regained their composure.
"We put a lot of emphasis on the 10 minutes before and after half time, and we scored a couple of tries just before half time and a couple afterwards. So they asserted their dominance and it was good to see they were capable of learning," Rogers says.
"We have to remember these guys are 18- and 19-year-old rugby players. They don't have 10 years of experience at senior club level. But it was great to see they were capable of making that change and getting back to playing the way they want to play."
Canterbury won their semifinal match against Wellington 39-22 yesterday , which means a Bay of Plenty and Canterbury final on Saturday, the first time this province has had the chance of taking the national title.
On form, they'll start as serious favourites to win, but their captain, who exudes considerable mana even at such a young age, is not taking anything for granted.
"We've put in the mahi. That's all that matters."
U19 scores
Bay of Plenty 68
(Tries: Lalomilo Lalomilo 2, Kaleb Trask 2, Kohan Herbert, Leroy Carter, Bartje Wierenga, Dennon Robinson, Dylan Williams, Emoni Nawara.
Conversions: Kaleb Trask 6, Cole Forbes 3)
North Harbour 12
(Tries: David Meki, Thomas Barham.
Conversion: Jack Heighton.)
