Residents of Port Chalmers and surrounding areas have welcomed moves by Port Otago to mitigate the noise from visiting container ships, but are hoping for more.
Emotions ran high at a gathering of affected residents in Port Chalmers last week, people describing being kept awake at night during the Rio class ships’ weekly visits by a low-frequency sound akin to a V8 car idling in their driveway.
In March alone, the Dunedin City Council received 24 noise complaints from residents in Port Chalmers, Roseneath, St Leonards, Carey’s Bay, and across Otago Harbour at Portobello, Broad Bay and even Harington Point.
Meeting organiser Raewynne Pedofski, who works from home in Roseneath and has regularly been disturbed at night by the noise, said it was a public health and wellness issue.
Port Chalmers resident Karen Elliot, who chaired the meeting, was less personally affected by the noise, but was struck by the emotional response of some people.
“The aim of the meeting was to give people a chance to talk, and to discuss ways forward,” she said.
“However, it was very clear that people were feeling exhausted by it and very upset.”
A resident of Port Chalmers for 27 years, Ms Elliot said people understood that they were living near a working port and major local employer, but it was important to find a way forward that would work for everyone.
Ms Pedofski is in regular contact with Port Otago chief executive Kevin Winders and was pleased by moves to mitigate the impact of the vessels.
These have included changing the berth window of the ships last week to reduce their visits to one night, moving them to the multi-purpose wharf, and having the ships run one of the noisy generators instead of two.
Speaking to The Star this week, Mr Winders said acoustic consultants Marshall Day took noise readings at the ship Rio De La Plata and at points around the harbour on Monday night.
This will be fed back to Maersk engineers in Hamburg who are working on ways to dampen the sound at source.
Mr Winders said Port Otago was the last port of call in New Zealand for the Southern Star service – operated by the six Rio class ships, which visited Tauranga, Napier and Lyttelton before Dunedin.
“By the time they reach us, they are carrying a lot of refrigerated goods, and here we load on lamb, cheese, beef, fish, apples and so on for Otago-Southland exporters,” he said.
From Dunedin, the ships made a quick transit to Malaysia.
“These ships have the capacity for 1250 refrigerated containers, which is great for our exporters, so the noise problem is very disappointing.”
By taking mitigating actions, Port Otago has been able to reduce the noise level by about 3 decibels, but at least another 10 decibels needed to be cut, he said.
“We have done just about everything we can to mitigate it, so now we are working with Maersk engineers to reduce the noise at source.
“And otherwise, we need to keep talking to people and letting them know what is happening – we want to be a good neighbour.”
West Harbour community board chairman Steve Walker and fellow board members were in regular discussions with the community and Port Otago on the issue.
“It is important to keep communication channels open with all people involved towards mitigating and ultimately finding a solution to a community problem,” he said.
Residents of Port Chalmers, Roseneath, St Leonards, Carey’s Bay, and Portobello have complained of the low frequency, throbbing noise emitted by the Maersk Rio class ships visiting Port Otago weekly.
The 63Hz, up to 120 decibel noise prompted 24 complaints to the DCC in March alone.
The noise comes from the massive generators required to power 1250 refrigerated containers – these cannot be switched off.
The Rio class ships started arriving over Christmas and were berthed for 30 hours, from 3pm on Sunday to Tuesday morning every week – keeping residents awake for two nights.
Dunedin’s warm, still summer nights allowed the noise to travel long distances.
Port Otago has moved the ships from the main container berth to the new multi-purpose berth, which has led to some improvement.
Last week, the window for the ships was changed to arrival at 6am on Monday and leaving by Tuesday evening, cutting visits down to one night only.
The ships are running one generator, instead of two, while at Port Otago to cut down on noise.
An acoustic consultant has taken readings on the ships and at St Leonards, Sawyers Bay, Roseneath and Portobello to feed back to Maersk.
Port Otago is working closely with Maersk engineers in Hamburg on ways to dampen the noise of the generators at source.