Awakened by splashing, we rushed on deck to watch a light show ensue. “Dolphins!” cried our captain, Dan. The cetaceans had chased sardines into an anchorage called Ladys Harbor on Santa Cruz Island, where we had pulled in for the night; they now careened around our boat's hull, blowing breath from their air holes and kicking up streaks of neon blue bioluminescence as they feasted. It was just one of the many magic tricks I have witnessed nature pull off while sailing California's Channel Islands. A landlocked East Coaster by birth, I married into a family of seaworthy Californians. Beyond Reason, the 38-foot sloop they keep at Ventura Harbor, is my home now for a week each summer. My wife, Jeanne, various members of her family, and I pack the galley with food and stow dive gear in the head. We secure paddleboards and a kayak to the lifelines, close the portals, and shove off.…