Sequence of images from underwater video of February 13, 2012 boat propeller accident in Sharm el-Sheikh in which a snorkeling diver was struck in the head by the propeller. Image 3.
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Houseboat Propeller Regulation Proposed and Withdrawn by USCG: Analysis by PGIC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