"My daughter Grace is always going on about what a great swimmer she is and she does not believe that I actually used to be able to swim," he said.
"So I said I will beat her in the 1km. I then had to sneakily go to the pool and swim 1km to make sure I could actually do it, which I can, so that's where it all came from.
"Actually the chances of me beating her are pretty slim but I am going to hold her down if I have to."
Grace is a well-performed swimmer at the Greerton Swim club with medals to show, so knocking over the 1km distance will not present too many problems for her.
This will be her and sister Ella's fourth time taking on the Sand to Surf after starting off in the kids beginner races and they are also actively involved in surf lifesaving.
"It's colder in the ocean and there are sharks and waves to worry about but I am looking forward to it and hopefully I will beat dad."
Jo is again taking on the 'I'm Going Long 2.6km swim and says she is better prepared than she has been in the past.
"This year I have been training with the Tauranga Swimming Club women's squad," she said.
"A few years ago I thought 'I am not going to run a marathon' but you know, mid-life crisis, I could actually do this. I am not as nervous this time because I did it last year, and I did the round Mount Maunganui swim in January, which is a bit further.
"But when I did those the sea was pretty flat so if it is a big sea then it could be a bit different.
"But for me I am in the back third of the race so it is all about doing it and personal achievement."