It ain’t sailing off Montauk, but there are surely worse ways to explore Brooklyn. Through September, the Gowanus Dredgers Canoe Club is offering free self-guided canoe tours of the canal, Wednesdays at 6 p.m. and Saturday at 1 p.m., the Park Slope Patch reports today. The boats launch from 2nd Street near Bond; see the Dredgers’ site for more info. Also, the Red Hook Boaters are offering free “walk-up” kayaking on Sundays from 1 to 5, from the end of Coffey Street in Red Hook. See their site for more info.