Houseboat Propeller Injury Avoidance Measures Proposed and Withdrawn by the U.S. Coast Guard: An Analysis by the Propeller Guard Information Center. A landmark paper on propeller guard issues.
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Houseboat Propeller Regulation Proposed and Withdrawn by USCG: Analysis by PGIC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