"The law makes the rules mandatory and says breaching them is presumed to cause unnecessary danger or risk.
"This case shows how the rules can work together. The right charts, keeping proper lookout and safe speed help give the skipper 'situational awareness' of what is happening around them and of possible risks to their vessel.
"Without that situational awareness Wilson did not see the danger to City Cat and grounded at 10.45am on a fine, calm day.
"It was a matter of luck that no one was badly hurt and, fortunately, no fuel was spilled into the harbour. City Cat was out of service being repaired for two weeks."
Wilson admitted he operated City Cat at least seven times in various parts of the harbour at speeds over the 5 knot limit within 200 metres of shore, he said.
On the Sunday of the grounding, City Cat was on a regular run between Wellington city and the suburb of Seatoun.
On board were 16 passengers, a deckhand and Wilson.
Although the City Cat ferry carried the general navigational chart of Wellington Harbour it did not have the detailed chart required by the Maritime Rules.
"The detailed chart shows a sudden shallowing of the water, and weed in the area 70 metres from shore. Weed indicates the presence of rocks.
"The weed is ordinarily visible to vessels travelling in that area at the correct speed of 5 knots."