12' Vessel stopped in water-15' from shoreline near Tulalip Bay.  Operator on starboard aft stood to urinate, lost balance and fell backward over straboard transom.  Operator grabbed vessel gunwhale- capsizing vessel to starboard.  Both operator and only other occupant entered water with PFD on person(s).  Boat remained floating bow up, while victims held onto bow yelling for help.  Victims were rescued by witness.
Marysville                    