Propeller Guard Information Center

Developing a Consumer Guide for the Selection of Propeller Guards and Other Propeller Safety Devices

This propeller guard selection guide is NOT ready for use. As brightly emblazoned on our documents, they are rough drafts. We posted them to generate a discussion that could improve them as well as provide some ideas to those working on the U.S. Coast Guard’s recently announced efforts to produce a consumer guide to propeller guards.

Our guide also covers safety interlocks, changing boater behaviors, boating safety classes and other boat propeller risk reduction activities.

Introduction to the Selection Guide

Our Propeller Accident Risk Reduction process is guided by three documents: Risk Proofing My Boat Against Propeller Injuries (describes the overall process), Propeller Risk Worksheet (large checklist that collects information to aid in decision making), and the Propeller Injury Avoidance Device Radar Plot (graphical representation of performance of various devices in different propeller injury scenarios).

Risk Proofing My Boat Against Propeller Injuries lays out the process, defines the terms, and identifies many possible actions that could make your boat less likely to be involved in a propeller accident.

It also teaches about five categories of Propeller Risk Reduction Activities:

  • Propeller Injury Avoidance Devices (guards, interlocks, kill switches, etc.)
  • Educational and Training Opportunities
  • Behavioral Modifications
  • Alternative Propulsion Systems
  • Warnings

Our Propeller Risk Worksheet records your answers to a series of questions in five areas:

  • Boat Specifications
  • Operator Experience and Environment
  • Water Conditions
  • Activities On and Near My Boat
  • Exposure Time and Boater Fatigue

to increase your awareness of your exposure to propeller injuries, and identify the areas of greatest risk.

Your answers to the Propeller Risk Worksheet can then be used with Risk Proofing My Boat Against Propeller Injuries to determine the best actions to take in order to reduce your risks, and if those actions include the use of propeller injury avoidance devices, your answers can be used in conjunction with our Propeller Injury Avoidance Device Radar Plot to select the device(s) that best meet your particular needs and desires.

Download Our Three Propeller Risk Mitigation Tools / Documents

The Propeller Injury Avoidance Device Radar Plot Chart by Itself

We suspected that it we did not post the chart here, many readers might miss it. This chart illustrates the format we are suggesting as a tool to help boaters select the best devices to meet their needs based on their answers to the Propeller Accident Risk (PAR) Worksheet. You can read more about it at Propeller Injury Avoidance Device Radar Plot

Propeller Guard Radar Chart

Propeller Guard Radar Chart

History of Our Efforts to Develop a Consumer Guide to the Selection Propeller Guards

Back in 2007 we started working on a guide to aid consumers in selecting the propeller guard that best met their needs. It quickly expanded to include safety interlocks, personal behavioral modifications, boating safety classes, and other opportunities. On November 3, 2008 we posted a spreadsheet we used to estimate and plot Propeller Safety Device Radar Plots that is almost identical the chart shown near the bottom of this page. We shelved the project about two and a half years while we worked on the houseboat study, but we have been thinking about it for quite a while.

Our Consumer Guide to Propeller Guard Selection vs. a U.S. Coast Guard Consumer Guide to Propeller Guard Selection Currently Under Development

On December 12, 2011, the U.S. Coast Guard held a webinar on the status of their recreational boat propeller guard testing efforts, and announced their intent to produce a consumer guide and an manufacturers guide to aid consumer and manufacturers in selecting the best propeller guards for their applications. During the webinar we said we had worked on creating a guide to aid consumers in selecting boat propeller safety devices that is still pretty rough and would publish our unfinished efforts in a “couple days”. This 16 December 2011 post contains the documents we spoke of.

We openly acknowledge our process is lengthy and complicated. Before anybody starts to blast us with comments about propeller guard selection being too complex for boaters to undertake, please remember the efforts some boaters put into selecting the optimal propeller for their boat AND note that USCG’s suggested propeller guard guide is a matrix of guard types across the top with three groups going down the left side (intended boat uses, what you are trying to protect, and top speed). For instance, if my intended use is fishing, and I am more concerned about boater safety than protecting my propeller or protecting aquatic life, and my top speed is 5 mph, USCG’s chart recommends a cage type propeller guard. USCG’s chart takes a minute or two to grasp (we think of it as a 3 dimensional chart with 3 tiers). It is obviously much easier to use USCG’s chart than our process.

The problem with USCG’s chart is if you take the same example we just discussed, except your top speed is 6 mph or more, it is unable to make any recommendations. While we may disagree with limiting cage guards to a maximum of 5 mph, our process also identifies many other things that same boat operator could do to improve their safety on the water without adding a guard. Our process includes taking boating safety classes, limiting alcohol consumption, making sure your boat is not overpowered or overloaded, visiting with your passengers about propeller safety, making sure an adult is assigned to keep an eye on every child on board, evaluating how crowded and how rough the water is, etc.

We encourage USCG to broaden their efforts as well.

The Future

As suggested in our Risk Proofing My Boat Against Propeller Injuries document, the worksheet could be moved online. An online Propeller Accident Risk worksheet could score itself in the five categories, and identify the greatest areas of risk to people in the water (the scenarios in the Radar Plot). Boaters could then directly use the radar plot to select devices to minimize those risks, as far as devices are concerned. The system could also suggest behavioral changes, educational opportunities and other activities to lower your risk.

If anybody thinks this is a great idea and would like to fund it, please contact us.


We obviously need your help to improve the process and welcome any comments you may have.

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