A penalty goal by Brenton Kramer was the only tangible evidence of the forward slog as Harbour eked out a win over Pirates in the wind, rain and chill at Hancock Park.
Kramer kicked the penalty midway through the first half after the Harbour forwards had dominated territory in the difficult conditions.
Pirates attacked for most of the second spell but it could not break down the Harbour defence.
It made crucial mistakes with the slippery ball, it was thwarted by resolute tackling and its territorial advantage was not even rewarded by a penalty within kicking distance.
Kramer kicked one out of two for Harbour and James Rosenberg missed his only attempt for Pirates, in the first half.
There was nothing in this game and a draw would perhaps have been a fair result, but Harbour deserved credit for its unflagging defence.
Locks Gareth McComb and Trent Sutton were top value for Harbour in the line-outs and tight and blindside flanker Brad Griffiths was tigerish in the tight-loose.
It was not a day for backs but James White was solid at fullback and Doug Edwards strong in midfield.
Pirates halfback Steve Bruce was a livewire and splintered the Harbour defence with a blistering break early in the second spell.
Warren Kearney was strong from No 8, Josh Clark was effective at lock and props Shane Parata and Daniel Johnson held up well against highly-rated opponents.
Harbour 3 (Brenton Kramer penalty goal), Pirates 0. Half-time: 3-0.
Referee: Ross Barnett.
