A coroner has found the circumstances around the death of a man who drowned in a wastewater tank on a fishing vessel in 2012 still cannot be established.
Mark Sweeny was the second engineer on board the Antarctic Chieftain, travelling from Nelson to Mauritius.
The 53-year-old from Richmond drowned after inhaling harmful gases in the ship's forepeak tank, used for holding ballast and offal.
He was working alone pumping ballast water from the tank, which required him to open its hatch but not to get into it.
In her report, Carla na Nagara says she was not able find how Mr Sweeny came to be in the tank.
She recommended the fishing industry consider making changes so tank hatches don't need to be opened when wastewater is being pumped, and says an observer should be present if they are opened.