Some possible rod, wire, strut cross sections for use in construction os boat propeller guards. By the Propeller Guard Information Center at PropellerSafey.com
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Houseboat Propeller Regulation Proposed and Withdrawn by USCG: Analysis by PGIC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