Charles River Dam Lock

(As of 8/11/20 the locks are opened after a summer long closure due to the North Washington Street Bridge demolition.) This dam consists of 3 sets of parallel locks. 2 sets are roughly 20'x100' and the third is about twice as big. The lock master monitors ch 16 and 13. To request passage sound two long followed by two short horn blasts. I'm not sure what the hours of operation are but I have been through the locks at 4 am and at midnight.