The inclusion of Paul Miller and Daniel Johnson early in the second half gave Pirates the resurgence they needed to overcome a determined Harbour side at Watson Park.
In what was an ill-disciplined encounter at times, both sides became guilty of handling errors and defensive lapses down the flanks.
The first half resulted in a stalemate between a side at the top of the table allowing itself to be dragged down by a team languishing near the bottom.
Harbour had its share of scoring opportunities but was guilty of turning many of its opportunities into solo attempts, which were shut down by the efficient Pirates loose forward trio of Dan Crichton, Josh Clark and Solomon T-Pole.
Shaun McCarroll was another to stand out in both the tight and loose, while Glenn Dickson's kicking game was efficient.
For Harbour, Craig Sneddon was efficient at fullback, while Brad Griffith and Dalton Ellie gave momentum to the forward pack.
- Pirates 29 (Kenton Leiataua, Paul Miller, Daniel Te Au tries; Glenn Dickson con 4 pen), Harbour 16 (Johnny Legg try; Lance Taylor con 3 pen). Halftime: 13-10 Pirates. Referee: Dave Kennedy.