U.S. Coast Guard Boating Safety Circular #77 dated August 9, 1995. USCG is seeking public comments on propeller safety on houseboats and other displacement vessels.
Aspects of the Propeller Safety Debate chart
Houseboat Propeller Regulation Proposed and Withdrawn by USCG: Analysis by PGIC
History of Boat Propeller Safety
Mitigating Boat Propeller Injuries & Fatalities Chart