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Silencers to cut the unwelcome noise from Rio-class ships berthed at Port Otago are on their way.
Port Otago chief executive Kevin Winders said an "at-source'' solution to the Rio class ship noise had been developed by Maersk engineers and put into action.
"I'm very, very pleased that they have taken this action,'' Mr Winders said.
Maersk Fleet group manager Clyde Peres said the solution involved fitting a large silencer on to one of the auxiliary engines on each Rio ship.
"Six of these silencers - one each for the six Rio-class ships in the rotation - have been manufactured in Lithuania and are being shipped to Singapore right now,'' Mr Peres said.
"They are expected at the Port of Tanjung Pelepas [in Malaysia] by the end of November and are planned to be retrofitted to the engines, as each Rio transits the port.''
Mr Winders said it was great that the world's largest shipping line had "listened, values the importance of our social licence and is now making a significant investment to solve the problem''.
The giant silencers will be fitted to all six Rio-class ships of the Southern Star service, which visit Tauranga, Napier, Lyttelton, and Dunedin to load goods for transit to Malaysia.
The first ship to receive a 5m by 1.8m muffler would be the Rio De la Plata.
Once the silencer is fitted and tested, work on the other ships will follow, although Mr Winders said he did not know the timeframe.
He did not know the overall cost of manufacturing and installing the silencers but, given that the Rio ships were valued at $100 million each, the investment would be "significant''.
Port Otago has been working with Maersk to address the low frequency "rumble'' emitted by the Rio-class ships since early this year, after complaints from harbour residents.
The noise originates from exhaust gas pulsation of the auxiliary engines running the ships' generators, which power up to 1250 refrigerated containers on board.
Because Port Chalmers is the last port of call before departing New Zealand for Malaysia, the ships are generally carrying a large refrigerated load of local produce such as lamb, apples, cheese and fish and the generators are working hard to keep products at the correct temperature for the duration of their journey.
As an interim step to reduce the impact on the neighbourhood, Port Otago and Maersk moved the ships' arrival and departure times to be in port only one weeknight, rather than two nights over the weekend.
In the meantime, both parties had continued working on an at-source solution.
Mr Winders said Port Chalmers and harbour residents should get their first chance to experience the newly silenced Rio de la Plata when it returned over the Christmas-New Year period.
"Fingers crossed that, come new year, we will see the first of the big red Rios with the retrofit complete and the beginning of the end to the unwelcome noise in our neighbourhood,'' he said.
Mr Winders said the community would be updated when a firm installation date for the first ship had been set.