Many think propellers only present danger when they are rotating. Propellers can be very dangerous even when they are not rotating, particularly stainless steel propellers as they tend to have thinner blades. High Performance and racing propellers can be even more dangerous due to their sharpness.
A 1993 paper, A Study of Boat and Boat Propeller-Related Injuries in the United States 1991-1992, by the Center for Disease Control used reports from the National Electronic Injury Surveillance System in conjunction with reports from Florida’s state wide trauma registry to estimate national propeller injury counts. The study estimated 670 people were injured during the year studied (Sept 1, 1991 thru August 31, 1992) by propellers on boats that were NOT rotating. Or with 95 percent confidence intervals that between 335 and 1,005 were injured by propellers on boat motors that were “off”. An Appendix to the study presents several individual accidents as examples. They range from stepping on the propeller, sliding off the rear of the boat and landing on the propeller, entering boat from rear when it struck a wake and foot hit the propeller, foot slipped off step while entering and struck propeller, 6 year old girl learning to ride a bike rode by a boat on a trailer and grabbed the prop to balance herself and was cut, swimmer approached rear of boat and their hand hit the propeller, swimmer knocked by a wave in the propeller, slipped off back of boat and foot struck propeller, etc.
A 7 March 2002 propeller victim letter (Lawson) to the U.S. Coast Guard in response to an open request for comments surrounding proposed propeller guard / prop guard regulations contains the testimony of a Maryland woman who was injured about 13 years earlier by a non rotating propeller. She was boarding the ladder when her right foot struck the non rotating propeller. She required 14 stitches, physical therapy, and was restricted from driving for some time.
These accidents, combined with propeller theft, and frequent trailering of small boats has led to several new products in the area of propeller bags and covers for use when in transit on trailers, propeller carriers for carrying propellers, full drive covers, and even propeller covers to protect boat covers from being cut by the propeller. These products and more are listed in the Propeller Covers and Carriers section of our list of Propeller Guards and Other Propeller Injury Avoidance Devices.
It is our understanding, that in the United Kingdom, trailered boats have to use a reinforced propeller bag or cover the propeller with a bucket when on the roads.