Sue Neill-Fraser has spent a decade in jail for her partner's yacht murder. She may be innocent.

It was January 26, 2009 and Susan Neill-Fraser and her partner Bob Chappell were spending the day working on their brand new yacht.

Neill-Fraser, who owned a horse riding school in Tasmania and Chappell, who was a chief radiation physicist, had plans to sail the ship named the Four Winds around Australia.

But after the fateful night that followed, their plan was well and truly over.

After a long day of work on the brand new $200,000 vessel, Chappell decided to stay on board overnight to continue repairs on the yacht as Neill-Fraser returned home.

It was the last time Chappell would be seen alive.

The next morning, the Four Winds was found half sunk in the waters at Sandy Bay.

A line had been cut to leak water into the boat and the cabin was found splattered with blood.

Chappell's body wasn't found and neither was the murder weapon but police were convinced – Chappell had been murdered and his killer had attempted to hide the evidence.

Before long, Chappell's partner Neill-Fraser became the prime suspect in the 65-year-old's death.

Despite the absence of a murder weapon, a number of clues pointed to Neill-Fraser.

First, police found a red jacket that belonged to Chappell's partner on the Sandy Bay waterfront.

Neill-Fraser initially denied it was hers, before later admitting that it was her own.

It was just the first in a series of lies that Neill-Fraser would tell police that would ultimately become her greatest downfall.

Susan Neill-Fraser's conviction.

In 2010, Neill-Fraser was convicted of bludgeoning Chappell to death, winching his body from the boat’s cabin to the deck and dumping it in the River Derwent. She was sentenced to a maximum of 26 years in prison with a non-parole of 18 years. Both were later reduced by three years. 

Following her conviction, Neill-Fraser and her daughters have tirelessly maintained her innocence.

"There is no doubt in my mind that mum is innocent. She did not commit this crime," Neill-Fraser’s daughter, Sarah Bowles said.

"I’m very confident that we are going to win this and mum should be acquitted at the end of it. We have very strong and compelling evidence that is going to be presented and I think as this plays out, we’re going to witness once of Australia’s biggest miscarriages of justice cases since the Lindy Chamberlain saga."

A decade later the murder case will be before the court in an appeal, after Supreme Court Justice Michael Brett described the case against Neill-Fraser as "entirely circumstantial".

A 2015 law allows appeals in cases where there is "fresh and compelling evidence," and in 2019 Neill-Fraser's legal team was able to convince Justice Brett of that fact, in the form of witness Meghan Vass. 

Speaking to 60 Minutes two years ago, Meaghan Vass, who was 15 and homeless at the time, changed her story.

Previously in the trial, she said she'd never set foot on the Four Winds. Now she says that she had.

"In particular, Ms Vass states that she was present on the yacht then with two identified male companions," wrote Justice Brett, as reported by the ABC.

"She witnessed at least one of the males assault Mr Chappell. She recalls seeing a lot of blood."

The appeal, which starts on March 1, will be heard before the full bench of the Supreme Court. 

It could either lead to a re-trial, her conviction could be quashed, or her appeal will fail. 

Neill-Fraser is eligible for parole in August 2022. 

This post was originally written in March 2019 and has been since updated with new information. 

Feature image: 60 Minutes.