Crescent Island, a large dive boat in Hong Kong that was involved in a 27 July 2008 fatal propeller accident. Image from investigative report.
Houseboat Propeller Regulation Proposed and Withdrawn by USCG: Analysis by PGIC
History of Boat Propeller Safety
Mitigating Boat Propeller Injuries & Fatalities Chart
Four Volume Review of the Boating Industry’s Boat Propeller Guard Product Liability Defense