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.