HMNZS Manawanui sinking: More sea water sampling after testing finds high hydrocarbon levels

More sampling will be carried out around the site of HMNZS Manawanui wreckage after testing found elevated levels of hydrocarbons.

The Royal New Zealand Navy ship, a specialist survey and dive support vessel, struck a reef on the evening of Saturday, October 5. It began to list and Commander Yvonne Gray gave the order to abandon ship.

A fire broke out in the engine room and the $100 million vessel sank the next day off the south coast of the Samoan island of Upolu.

The Defence Force said almost 1000 tonnes of diesel were on board the Manawanui before it sank.

HMNZS Manawanui off the southern coast of Upolu, Samoa. Photo / NZDF

Analysis of the seawater conducted shortly after the sinking by the Science and Research Organisation of Samoa (SROS) found elevated levels of hydrocarbons, which prompted the Samoan Government to implement a precautionary zone.

Hydrocarbons are the primary components of fuel products like petrol, fuel oil, and diesel fuel.

“SROS has requested New Zealand Defence Force (NZDF) assistance in conducting updated sea water sampling beginning this week within the precautionary area,” NZDF said.

“NZDF will be providing boat transport to take an SROS technician to sites designated by them where they will take samples which will then be analysed in the SROS laboratory.”

The NZDF senior national representative for operation resolution, Commodore Andrew Brown, said helping Samoan authorities conduct seawater testing was a worthwhile use of resources.

“The NZDF appreciate the importance of the marine and coastal environments to the people of Samoa,” he said.

SROS will give the results from seawater monitoring to the Samoan Marine Pollution Advisory Committee, which will decide on the extent of the precautionary area.

Prime Minister Christopher Luxon has previously promised to do “everything it takes” to try to minimise the environmental damage from the sinking.

In October, Luxon said he had spoken with Samoa’s Acting Prime Minister, Tuala Tevaga Iosefo Ponifasio.

“Our focus now moves to making sure we can mitigate and minimise any environmental impacts,” Luxon said.

“They welcomed any and all support we can offer, and that’s what we plan to do. We’re going to do everything it takes to make sure we do the best we can to minimise the environmental impacts.”

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