RedactedNarrative: Vessel #1 was tied to the dock by only a bow line.  Occupant #2 (an 83 year old female) was attempting to board the vessel.  She put her left foot on the swim platform of the vessel, causing the stern to move away from the dock.  Occupant #2 fell into the water scraping her right leg and her right arm against the dock.  She scraped her left leg against the boat.  Her head went under the water two times before she was assisted to the swim platform ladder by occupant #1 and a witness.  Transported by EMS to Magruder hospital.