Susan Blyth Neill-Fraser, 56, has pleaded not guilty to murdering Bob Chappell, a medical scientist who went missing from the couple's yacht Four Winds in January 2009.

Mr Chappell's daughter, Kate Chappell, told the court that in about 2004 Ms Neill-Fraser initiated a conversation about Mr Chappell's will.

"(It was) out of the blue, really," she said.

"She (Ms Neill-Fraser) said that my father had remade his will and that it was all quite fair."

Ms Chappell said Ms Neill-Fraser also told her Mr Chappell had "a lot of" superannuation and that she expected his three children would each inherit between $100,000 and $200,000.

Ms Chappell said her father and Ms Neill-Fraser had different plans for Four Winds, which they had bought in Queensland in late 2008.

Ms Neill-Fraser and two professional yachtsmen sailed the boat from Brisbane to Hobart in December 2008, but Mr Chappell flew to Hobart because he was hospitalised during the beginning of the journey.

"She (Ms Neill-Fraser) was very excited about the trip she'd had down ... (she was) quite enlivened by it and quite excited about it," Ms Chappell said.

She said this caused her some concern as her father had wanted to sail the boat locally.

"I just felt that Sue wanted to keep on sailing ... I couldn't imagine her settling in to do little trips," she said.

The court heard police seized a computer from Ms Neill-Fraser's home that showed internet searches for the Galapagos Islands, Panama Canal and numerous international yacht buying websites.

Mr Chappell's sister, Caroline Sanchez, visited Hobart in January 2009 from Sydney, where she then lived.

She said she accompanied her brother and his partner on a trip to Bruny Island on board Four Winds on January 25, which she described as "a happy day" with no arguments.

The court heard a brief exchange about 7am the following day was the last time she saw her brother.

Mrs Sanchez said she extended her stay and remained in Hobart for about a week after her brother's disappearance, which she learned of on January 27.

She said that when she returned to Sydney she was in frequent contact with Ms Neill-Fraser by telephone.

She said during one of these conversations in early March, Ms Neill-Fraser told her some comments made by a friend of Mr Chappell's youngest daughter had disturbed her on the night of January 26 and that she had driven to Marieville Esplanade where Four Winds was moored.

Mrs Sanchez said Ms Neill-Fraser told her she saw the boat was in darkness so she drove home again.

Mrs Sanchez said Ms Neill-Fraser told her on the morning of March 23 that she had left her car at Marieville Esplanade and walked home that night.

"I was surprised that she would walk back from Sandy Bay all that way at night around 12 or 1 o'clock,"

Mrs Sanchez said she was visited by Tasmania Police detectives that afternoon.