TAIC has revealed the boat had leaked petrol into the air pocket, which likely reduced the chances of survival for those inside it.
“All of the deceased showed symptoms of petrol exposure consistent with inhalation.”
Being exposed to petrol in a confined space reduces survivability as petrol attacks the cardiac and central nervous systems.
“In low concentration levels, people can experience the smell and irritation of the eyes and upper respiratory tract. High levels of exposure can rapidly lead to confusion, loss of consciousness and sudden death,” the report read.
When the boat capsized, two people were ejected from the vessel and eight were initially in the air pocket.
The skipper and two others swam out immediately, but one other person surfaced under the hull and tried to tell the others under it to swim out. They noticed the air “did not feel good” and swam out from under the boat.
The police dive squad, who entered the air pocket later noticed a “very strong” smell of petrol.
Chief investigator of accidents Naveen Kozhuppakalam said the petrol had almost certainly leaked from flaws in the fuel system.
“A pipe connected to the secondary fuel tank vent hose had a hole that was the main source of leaked fuel. It presented a hazard that risked fire or explosion if the fuel leaked when filling the tank, or risked fumes in the air pocket if the boat overturned.”
As well as this, the secondary vent hose did not vent outside, but into a sealed metal tube fitted to the rear of a boat.
There was also a second leak from the primary fuel tank vent hose where it joined the fuel tank - and this should have been sealed with a hose clamp.
TAIC is now calling on Maritime New Zealand to urgently address this problem, saying hundreds of boats just like i-Catcher are in the commercial fleet, and tens of thousands more are in the recreational fleet.
They say Maritime NZ does not adequately assess the integrity and safety of fuel systems on boats because the rules don’t require the entire fuel system to be inspected.
Chief Commissioner Jane Meares said the issue goes further than just the i-Catcher.
“It’s nation- and system-wide. Everyone on board a boat deserves to be safe.”
Kozhuppakalam said the vessel had been inspected by five marine surveyors and not one report showed an inspection of the fuel system below the deck plate.
“Surveyors are more likely to discover deficiencies if they are required to inspect the whole fuel system as a critical item - not just the parts that are easy to get to.”
Vita Molyneux is a Wellington-based journalist who covers breaking news and stories from the capital. She has been a journalist since 2018 and joined the Herald in 2021.