Living in Lyttelton – Rules of the Harbour
Power doesn't always give way to sail. Cargo ships don't give way to anyone.
The rules of Whakaraupō/Lyttelton Harbour are the same as for most bodies of water in New Zealand. Power gives way to sail, unless that power is:
A jetski manned by an idiot, or
A huge cargo ship being maneuvered into port by tugs.
Even the Diamond Harbour ferry, which runs to a schedule, can be held up by these cargo ships once in a while.