July 21st Saturday - Splash Into Summer Open House - FREE boat rentals 1-3 pm (no regular rentals 12-4 pm). Free parking on Grand Avenue. Boat rides typically last about 1/2 hour.
More info: http://www2.oaklandnet.com/Government/o/opr/s/boating/OAK029815
and
https://www.oaklandca.gov/events/national-safe-boating-week-open-house-1
Lake Merritt Boating Center
568 Bellevue Avenue, Oakland, CA 94610
(510) 238-2196