Booth family spokesman Chris Innes said all three crew members were highly-experienced and professional, and were working on a modern, well-maintained vessel.
"There's no good reason why this could have happened," he said.
"That's what everybody that I have spoken to is struggling with - how could this happen?"
A police investigation into the sinking is ongoing. The Transport Accident Investigation Commission (TAIC) also has investigators working with search authorities and Ocean Fisheries on an investigation plan.
The Booth family appreciates that the inquiries will take some time to complete, but are hoping for some "preliminary answers" once the boat is found.
The "main priority" is getting the men home, Mr Innes said.
"Obviously everybody is frustrated that the recovery is taking a bit longer than it should, but they understand there are safety considerations and so forth," he said.
Mr Booth has been at sea for the best part of 40 years.
"It's his life basically. His first job was fishing and he always had a knack for it, and while he did a few other things here and there, he always came back to it," Mr Innes said of his mate.
He described him as a "very experienced, very confident, straight up person" who would not be afraid to raise issues as he saw them.
Mr Booth's wife, Michelle and the couple's young daughter - who they do not want to be named in the media - are "well surrounded by solid friends" while they wait for him to come home.
The families of the missing crew are being supported by police, Victim Support, the crew's Lyttelton-based employer, and their respective friends and family, Inspector Craig McKay said yesterday.
"It's a difficult time for both the company, and obviously, more so for the families," Andrew Stark, chief executive of Ocean Fisheries and Stark Bros said on Sunday.
The three men on board were familiar with the Jubilee, Mr Stark said.
"They're all experienced with the boat."