As the sun set and the moon rose over a balmy Stinson Beach last Tuesday, Logan Walker, captain of the Chandalar, hung from the mast of the 33-foot beached vessel, dressed in scuba gear as he tied lines to the spreader. He and his newfound crew—a mix of locals and inspired visitors from over the hill—were planning a grand escape at high tide at 11 p.m. 

Louis Tenwinkle, a mariner from Richardson Bay who…