Winger Ezra Togia opened their account but his team were under a bit of pressure from the Vipers until centre Bernard Gregorus cut loose.
His 80m run from a scrum feed set up winger Paul Ulberg scoring, then a great pass by goalkicking halfback Rubin McCormick found Gregorus at pace to dart over.
Gregorus' tall centre partner Nemani Waka crossed shortly after the resumption and then prop Robbie McKenzie threw the dummy to pivot and muscle his way over underneath the black dot.
From 26-0 down, the Vipers could not turn the tide as basic pop passes were grassed inside the Orcas' half, Koro sadly no exception.
Wellington second rower Jon Masaga got across from dummy half, then speedy fullback Anthony Utanga finished off a long breakout from the Orcas own half as standoff Edward Albright took over the conversion duties.
Waka went on another long rampage and from the next tackle Togia had his second try going blindside from dummy half.
The Vipers were still game for one last throw of the dice as a Davis break saw his Orca opposite Dominik Bartels sinbinned for a foul with just over a minute left.
Working forward, the ball was spread to Barlow who forced the ball down through two tacklers right on the siren.
In the curtain raiser game, the Vipers Under 17s gave the Cooks Gardens fans cause for optimism for the future when they put down the Orcas Under 17s 42-28.
Leading 18-10 at halftime, the Vipers U17 were comfortably in front for the duration of the match.
The other game between Wanganui College Girls and Taranaki College Girls was cancelled after Taranaki withdrew the night before, citing injuries to squad members.