A coroner has recommended the introduction of mandatory carbon monoxide alarms in all boats and vehicles with sealable cabins after a "talented and experienced" sailor died after succumbing to fumes from a gas stove he had been using for warmth.
Naval architect Nicholas Banfield, 23, had picked up his girlfriend at Glebe and sailed to Middle Harbour for a romantic meal moored off Balmoral Beach on July 1, 2016.
After a feed of nachos and one alcoholic drink, the couple retired into the cabin of his 8.4-metre timber vessel Aquarius.
And with a winter chill in the air, Mr Banfield and NL, who can not be identified, sealed the hatches and turned on the LPG stove to keep the cabin warm.
The decision would cost Mr Banfield his life, and nearly claim that of NL.
The woman awoke two days later and made a confused call to her mother before police and Mr Banfield's employer, the well-known sailor Sean Langman who owns Noakes Boat and Shipyard, began to search for Aquarius.
They quickly found it still moored off Balmoral Beach after midday on July 3, only to discover Mr Banfield dead and NL in need of immediate medical treatment.
An autopsy found Mr Banfield had died from a lethal dose of carbon monoxide poisoning and it was "very difficult to know how NL survived", Deputy State Coroner Harriet Grahame said in her findings on Monday.
Ms Grahame said it was generally believed there was an under-reporting of carbon monoxide deaths across Australia.
"While it is difficult to be certain of the number of annual deaths caused by accidental exposure to carbon monoxide, it is clear that there is a large potential risk in the leisure industry," Ms Grahame said.
"Gas appliances are commonly installed in recreational vehicles, boats and caravans.
"Gas is often used to fuel cooking appliances, water heaters and refrigerator units. Risk exists whenever the appliances are not installed properly, or are faulty or if they are used without proper ventilation.
"Given the confined space of leisure vehicles and craft, the risk appears higher than when such appliances are used in a house or open area.
"The problem is exacerbated as carbon monoxide is invisible, odourless and tasteless.
"It is known to cause significant health problems at very low atmospheric concentrations and can cause death within minutes if levels rise quickly."
Fire and Rescue NSW experts performed tests aboard the Aquarius and found a "moderate" level of carbon monoxide was present after 98 minutes.
Ms Grahame said Mr Banfield, who had grown up in Tasmania, was an intelligent, talented and experienced sailor who had been on the water since he was aged seven and had a "good understanding of current safety standards within the boating industry".
The inquest heard the shock of the death of his employee had prompted Mr Langman to advise boat owners to install gas detectors.
But despite his company seeing about 3500 boats a year, only two owners had installed the potentially life-saving equipment since Mr Banfield's death.
"Nicholas Banfield was an intelligent and careful sailor with many years of experience," Ms Grahame said.
"That such a tragedy can befall him, in itself calls for a re-thinking of the regulation of this environment.
Ms Grahame formally recommended the introduction of legislation for mandatory carbon monoxide alarms in "all recreational and leisure craft and vehicle with sealable cabins, including sailing and motor vessels, caravans and motor homes".
She also recommended more safety initiatives to educate the public on the dangers of carbon monoxide poisoning.