Row, row, row your boat

Photos by John Blanding/Globe Staff

In boats of all sizes, and even on boards, participants in this year’s Blackburn Challenge took from two to six hours to complete part or all of the 20-plus-mile course on July 20. The challenge is an annual open-water circumnavigation of Cape Ann. As participants row or paddle in the open ocean, conditions can vary dramatically. At right, Caroline Gould pedals her way along the course.