Lost New Zealand Survey Vessel's Tanks are Intact, Limiting Pollution

Oct 18, 2024

Published Oct 9, 2024 6:18 PM by The Maritime Executive

The Royal New Zealand Navy received good news Tuesday when salvage divers visited the wreck of the survey vessel HMNZS Manawanui, which ran aground, burned and sank off Samoa last weekend.

Manawanui went down on the slope of a reef, damaging about 5,000 square meters of coral on the way down, and initially there was uncertainty about how far she went down before coming to rest on the bottom. Given the steepness of the bank, the wreck's depth could have been as much as 150 meters, making pollution-response and salvage operations much more difficult.

Instead, the responders found the ship in just 30 meters of water, well within reach for commercial diving methods. Manawanui came to rest on her starboard side on a flat rock shelf, rather than an uneven bed of coral - a further stroke of luck.

"There are salvage techniques which would basically allow an organization to remotely drill into the side of the hull, and it's fairly easy at 30 metres depth to extract the fuel - because the vessels lying on it's side - you don't have to start drilling down through superstructure to get at the fuel tanks which are mostly lying at the bottom of the ship," salvage consultant John Riding told RNZ.

In further good news, divers found that Manawanui's fuel tanks are intact and undamaged, and the ship is only seeping diesel fuel from three pipe locations. Almost all of her 950 tonnes of diesel fuel remain in place. The limited release of pollution has produced a sheen at the surface and a strong smell of diesel on shore, but so far no major spill effects have been observed on the adjacent reef. This will come as a relief to local subsistence fishermen, whose families are reliant on the reef for sustenance and income.

The divers also managed to recover the vessel's voyage data recorder (VDR), so investigators will have much more information to work with to determine the cause of the casualty. The service has launched a board of inquiry process to determine root causes and make recommendations.

Three shipping containers from Manawanui's deck drifted loose and came to a rest on the reef, according to 1News. A visible sheen was also observable.

"We want to get all the hazards out of the water, all the hazards off the beach. We need to interact with the locals, we need to get to villages and understand the situation," dive team leader Lieutenant Christian Lloyd told 1News. "We want to help, we're here to help, and we'll stay as long as it's needed."