Dunedin residents say a new type of container ship sounds like "a V8 running in your driveway".
A petition on behalf of residents concerned about the disruptive vibration and noise from larger ships berthed at Port Chalmers was presented to the Dunedin City Council environment committee meeting on Tuesday.
Port Otago chief executive Kevin Winders acknowledged the concerns, which came from both sides of Otago Harbour, and as far as the suburb of Waverley in Dunedin.
"Personally I pray for a big southerly each week," Winders said.
That wind direction would blow the noise away from residents, but was not a solution to residents experiencing sleepless nights.
Winders saidcomplaints started in November, when the Rio class of container ships began arriving at Port Otago.
The port company, which is owned by the Otago Regional Council, was "excited" by the arrival of the ship, which was shorter, wider, and sat higher in the water than previous container ships.
The 10-year-old Rio-class vessels, of which there were six worldwide, could hold a capacity of 5300 containers.
They were often around 80 per cent full when they arrived in Dunedin, following port calls in Tauranga, Napier and Lyttleton.
There were also complaints made in other centres, most notably Lyttleton in Christchurch, but not to the same extent as Port Chalmers.
Winders likened the sound to "a V8 running in your driveway".
To mitigate the disruptive noise, the arrival times of the Maersk ships had changed at a significant cost to the shipping giant, which was also down to running one generator, rather than two, Winders said.
"It is not a five-minute fix," he said.
A project team was formed, and was looking at trialling the retro-fitting of a giant silencer to alleviate the low thumping sounds emerging from the generators.
The plan was to retro fit one of the ships, and make sure it worked before trialling another one, Winders told councillors.
The silencer would not change the decibels eminating from the vessels, but the aim was to change the pitch, he said. That would bring the sound to a similar level as the previous line of cargo ships.
That trial could be within the next four months,
The vessels would not be as busy over the winter period, arriving on Monday morning and leaving that night.