Son tells court dad had a lot to live for

Susan Blyth Neill-Fraser, 56, of West Hobart, has pleaded not guilty to murdering Mr Chappell, her partner of 18 years, who was last seen on board the couple's yacht Four Winds on Australia Day last year.

Bob Chappell's son, Timothy, yesterday told the court his father had just commissioned a major piece of cancer treatment equipment for the Royal Hobart Hospital.

He said that his father felt he was the only person with the knowledge to write the manuals for the equipment and that he had wanted to complete the project before retiring.

"(It was) the last big thing of his career; he wanted to finish it," Mr Chappell said.

He said that Bob Chappell and Ms Neill-Fraser had different plans concerning Four Winds, which they had bought in late 2008 in Queensland.

Mr Chappell said that this difference was causing tension in their relationship.

He said that Ms Neill-Fraser had wanted to go sailing while his father was happy "to sit on it and drink some nice wine".

Mr Chappell described two visits he made to Four Winds with other family members, during which time he said the tension was apparent.

"I felt a bit uncomfortable on the boat because of the tension between them," he said, describing "a few snipey-type words".

Mr Chappell said that he was surprised to learn on the morning of January 27 that his father had spent the night on Four Winds without the dinghy - which Ms Neill-Fraser said she had rowed to shore on January 26 with plans to return the following day to collect her partner.

Mr Chappell said that his father and Ms Neill-Fraser were both "extremely safety conscious" and that his father's initial thought would be that he would need the dinghy in case something went wrong and he needed to get off the vessel.

He described Bob Chappell as an introverted sort of person who "could get grumpy and prickly quite often" but was never aggressive.

Under cross-examination, Mr Chappell told the jury Ms Neill-Fraser had always been instrumental in making sure Bob Chappell kept in touch with his three children, and that she often invited them for meals.

Bob Chappell's body has not been found.

The trial before Justice Alan Blow continues.