MerCruiser stern drive propeller proximity to a swim ladder is shown. The swim ladder is very close to the propeller, and the drive is not even steered over that direction. Photo taken at a Tulsa Boat Show by Gary Polson.
Houseboat Propeller Regulation Proposed and Withdrawn by USCG: Analysis by PGIC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