Andy's Dad Dennis taught Andy (and oftentimes Mia) everything he knows. Dennis started sailing in his mid-twenties with Andy's mom Gail - their honeymoon was to the Bahamas in the 70's with a captained charterboat. When they were just 28 and 30, they took off on an old Phil Rhodes-designed Chesapeake 32 and spent the winter cruising the Bahamas.
Dennis has sailed many thousands of bluewater miles and stands in for Andy when he can't (like when he got appendicitis offshore!). Dennis is also super-supportive of the whole charade, and Andy & Mia use his basement as temporary storage when they're home. Sadly, Gail died of brain cancer in 2012.