Because everything’s better by boat, Boating constantly engages the world by water. We’ve fished, skiied, tubed, boarded and surfed. We’ve raced, run whitewater, rescued, and embarked on adventures to Communist countries. We’ve gone to rock concerts and pro sports games by boat, and we’ve rafted up in party coves But this time, we’re here for the beer. More precisely, the microbeer: the crafty, flavorful alternative to the massproduced product proffered by the international brewing industry. In the last 20 years, microbreweries seem to have popped up on every street corner in America. I can walk to three of them from my home office. But brew-hopping, we figured, would be better in a boat. An opportunity materialized on the new Afina 3950, moored in Jacksonville, Florida, on the St. Johns River…