Their son, six-year-old Niky, suffers from a rare form of asthma.
It's hoped that the clean air at sea will improve his condition.
The family will cruise in the open sea, calling at ports only to refuel and buy food.
But being at sea doesn't mean that Niky will have the perfect excuse for missing school.
Niky will be linked by webcam and a satellite dish to a classroom computer at a school on one of the islands.
But unlike schoolchildren studying on land, Niky will have sunny skies and a sea breeze to make lessons that bit more enjoyable.