• Writing an in-depth response to the U.S. Coast Guard's withdrawal of NPRM 10163, the proposed requirements for for propeller injury avoidance measures on recreational nonplaning houseboats.

• Posting a list of propeller guard tests and propeller test reports from marine drive manufacturers, propeller injury avoidance device manufacturers, boat builders, boat rental operations, the U.S. Coast Guard and others.

• Putting together a "Who is Who" list of those currently and historically involved in propeller injury avoidance.

• Finishing a tool that allows boaters to evaluate the risk of propeller injury to them and others on or near their boat based on their specific situation. It helps boaters select the best methods to reduce their risk. The tool is built around a check list that evaluates their risk for specific types of propeller accidents (like running over people being towed by others, running over swimmers, running over someone that fell in from your boat, etc.) based on their exposure due to operator error, behavior of those on their boat, specifics of their boat, their on water activities, activities of others on the water, water conditions, potential for underwater obstacles and other variables. The check list also evaluates their need for boater safety education and behavioral modification, as well as their exposure to risk from other boaters.

  The checklist is accompanied by a written discussion and a group of radar charts showing the relative degree of avoidance/protection offered by various devices to specific types of propeller accidents. In addition to helping boaters select the appropriate device(s) to reduce their greatest exposure to propeller injuries based on their exact situation, it also prescribes boater safety education, and behavior modification where appropriate.

• Analytically examining the drag of cage type propeller guards and focusing on two approaches that may drastically reduce their drag at higher speeds. As part of this project we will also be resurrecting some novel approaches to estimating and mathematically representing drag I developed many years ago.

• Studying the possible application of two old Brunswick trim cylinder system patents (U.S. Patent 3,999,502 and U.S. Patent 4,050,359) to cage type propeller guards. The patents describe a method that allows a marine drive to freely swing up and over obstacles when striking them at slow speeds. This is in addition to the pressure relief valves and memory piston system normally used to rise up and over obstacles struck at high speed such as submerged logs. These designs were initiated by Brunswick to help prevent people from being thrown from a boat when striking an obstacle at slow speed (not enough momentum to open the system for high speed strikes so the boat abruptly stopped, or if their was enough momentum there would still be an abrupt jerk as they kicked in).

  The approach described by the patents may have application to propeller safety in two manners. (1) Reducing blunt trauma to people and marine mammals (like manatees) that might be struck by a guard at slower speeds. (2) Protect guards themselves from damage due to striking rocks, other obstacles, or striking bottom at slow speeds. The drive would just swing up with minimal impact to the guard.

  The forces on the guard during a slow speed forward impact would be limited to the propeller thrust and the forward momentum of the lower unit of the drive. Those forces would even be somewhat counterbalanced by the momentum of the portion of the drive above where it hinges.

  Proper sizing of the components might significantly reduce blunt trauma loads to people and impact loads to drives on up into midrange speeds.

  The two Brunswick trim system patents can be viewed by entering their patent numbers 3,999,502 and 4,050,359 one at time into the search box at Google Patents. The interesting part is what they call "trail out" at low speed impact.

• Studying propeller accidents outside the U.S. to those visiting that country from another country. We have become aware several international vacationers are being struck by propellers at tourist destinations that focus on water activities (Cancun Mexico, Cozumel Mexico, other Yucatan Peninsula sites, Fiji Islands, Hawaii, the Caribbean, and other well known snorkeling / diving/ beach areas). We are focusing on people from one country being injured in another country while on vacation at a major tourist destination.

• Continuing to work on the concept of a flip up guard for houseboats and pontoon boats we have been pursing for some time. It is a convention cage except the end cover (cap) to the rear flips up when underway due to a tab near the bottom of the flip up portion. The tab creates enough weight to pull the cap down when at rest, and enough resistance to flow when going forward to cause the cap to rise and ride parallel to the surface when underway. The design reduces drag when underway, while still providing full protection to the rear when stopped or backing up.

• Continuing to develop and study the concept how local propeller accidents "vaccinate" area boaters with a "perceived vulnerability" to propeller injuries and push them toward being safer boaters, at least in the short term. We are gathering research on the impacts of other types of accidents on behavior changes and resulting safety records of individuals.

• Drawing a huge "Fault Tree" that uses logic "ANDs", "ORs", etc. to show how and where various propeller injury avoidance devices try to break the accident chain and which accident chains they can and cannot break, as well as how multiple propeller injury intervention devices and approaches interact with one another.

• Following up on some propeller flow and wake studies that appear to open up a concept nobody seems to have looked into before. It involves the inflow path to propellers when they are not advancing (when the prop is turning but the boat is not moving, like when the boat is just starting to take off) and concerns the slope of the open surface of the water on the suction side of the propeller.

• Following up on several leads for more information on past houseboat propeller injury accidents as we continue to fill in our Houseboat Propeller Accidents Log

• Studying the broader topic of communication and health behavior looking for some tools and methods that might be useful in encouraging people to be safer around propellers.

• Launching a new web based portal that we think will be vital in encouraging college students to do design and research projects in the area of propeller safety.

• Investigating the use of propeller danger / caution / warning decals.

• Studying the effectiveness of propeller safety educational efforts vs. use of propeller injury avoidance devices.

Feedback

If anyone has any comments, suggestions for areas of study, or would like to help in these efforts, please see our How Can I Help page or email us.

Return to Propeller Guard Information Center

---