prop guard opinions

Discussion in 'Props' started by Flying Flivver, Mar 27, 2012.

  1. Ike
    Joined: Apr 2006
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    Ike Senior Member

    I have been involved with the prop guard issue since the 1980's. The USCG has been researching it and dealing with both the advocates and the opponents for longer than that. In the mid 80's I was the project manager on one of the USCG research projects on prop guards. I also held public hearings in Florida and Maine in the late 80's on this subject. So over almost thirty years I have definitely formed some opinions about their effectiveness.

    At speeds up to about 10 knots prop guards can be an effective way to prevent catastrophic prop strike injuries. At speeds much above that and beyond they are not. Being struck by a boat, a skeg, or any underwater part of a boat will cause traumatic injuries especially to the head. This has been demonstrated through actual tests using dummies (no humans were used, no matter how dumb they are. )

    Prop guards do have their place but they are not the only answer.
    The first is operator education. Never run the engine when you have people in the water. Maneuver to pick them up then shut off the engine.

    If people are swimming off your boat, anchor and shut off the engine.

    Operators need to tell people on their boat about the dangers of an exposed propeller.

    Operators need to know where everyone is and what they are doing when getting the boat underway. (there was a particularly grisly case where a very intoxicated young male dove off the swim platform on a houseboat just as the operator started to back down. I was one of those who had to deal with his mother. It was not pleasant.)

    Swim areas need to be better marked and boat operators need to know where they are and stay away from them. This not only applies to boats with props, but jet boats as well.

    Jets are an alternative solution but only at low speeds. At planing speeds they still present a hazard to anyone hit.

    Other devices such as kill switches that shut off the engine when someone falls overboard, or interlocks when the boarding ladder is lowered may be more effective. There are also various alarms that can be had to warn about people in the water, or if the boat is backing.

    Prop guards do affect top end and fuel consumption on planing hull boats. They also affect maneuverability, but how much depends on the type of prop guard.

    Not all prop guards are created equal. Different types have different characteristics. The type you use depends on what you are trying to do. Some are designed only to keep weeds and debris out of the prop. Others are designed to prevent people from getting body parts in the prop. So the prop guard has be chosen for it's function.

    There are significant differences between prop guards and nozzles designed to improve the efficiency of the propeller. The two should not be confused. They do two completely different functions.

    Believe it or not research has been (and probably still is) done on ways to detect people in the water by a speeding boat, and immediately stop the prop. Unfortunately this doesn't work very well. Nothing useful has come out of it yet. Forwarding Looking Sonar simple doesn't give enough warning time, not even for rocks and logs and such that present much better targets than humans., except at very low speeds.

    Last but not least by any means, the market. On the whole, boat owners simply don't want them. Prop guards have been available as an option from most outboard manufacturers for over 30 years. Some boat manufacturers offer them too. There are a variety of prop guards available on the aftermarket. Hardly anyone buys them. Why this is, who knows. Perhaps most boat owners don't know they are available. The engine makers aren't pushing them either. But my sincere opinion is most people don't want them until something catastrophic happens.

    Prop strikes are not rare. They are a small number of the total accidents. In 2010 out of 4604 reported accidents there were 49 struck by propeller accidents and 31 struck by vessel accidents. 1 of those was a fatality. But unfortunately when they do they are almost always catastrophic for the injured person resulting in permanent disabilities and life long need for medical care.
  2. Flying Flivver
    Joined: Oct 2011
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    Location: Ottawa ON canada

    Flying Flivver Junior Member

    I know understand and practice the safety protocols my thoughts were just of added insurance. thank you for your opinions they are valued.
  3. tunnels

    tunnels Previous Member

    Guards or no guards it all comes back to the person standing at the wheel with a hand on the throttle lever !!
    He or she is 110% totally responsable for the boat! its operation! plus all the other people!! in the water and in the boat!!
    Accidents dont just happen ,they are made to happen by peolple that are careless , imature or irresponsable !! so a prop guard isnt going to help much !!:(
  4. chartman
    Joined: Nov 2008
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    Location: Stillwater, Oklahoma

    chartman Junior Member

    Propeller Accident Statistics

    To Ike:
    Thanks for sharing some of your historical experiences surrounding the propeller guard issue. It was nice to see someone talking level headed about the issue.

    However, you made a major error in the statistics you provided. USCG logs boating accidents as a series of 3 events. For example: Event 1=stuck submerged object, Event 2 =man overboard, Event 3= struck by propeller.

    The statistics you provided were for Event 1 ONLY. They did not include accidents like the one I modeled (struck something, fell overboard, then struck as Event 3).

    USCGs reporting method is confusing to many people. Reporters and professionals such as yourself have been getting the statistics wrong for decades. That is part of why so little attention is paid to the problem (real statistics hidden from view).

    We ( have a page explaining how to properly read the USCG Annual Boating Statistic report at:

    For example, the 2010 data you reference (49 strikes, 1 fatality) comes from USCGs Event 1 data in their Table 16 in their Annual Boating Statistics 2010 publication.

    The correct 2010 data (combined for all three events) is shown in USCG's Table 17 as 178 strikes and 27 fatalities.

    The 2011 data was reported since your comments. It shows the counts up considerably (197 strikes and 35 fatalities).

    These are the actual USCG numbers. That does not take into account accidents not reported to USCG and accidents reported that do not meet their criteria to be listed.

    As you mentioned, these accidents are not rare, but they are a heck of a lot less rare than the statistics you provided. You are certainly not alone. We see countless others making the same error. Thanks again for sharing your thoughts.

    gary polson
  5. Ike
    Joined: Apr 2006
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    Location: Washington

    Ike Senior Member

    Gary, Long time, no see. I retired in 2004 so I haven't been in DC much since then.

    What you say about statistics is true. Mark Twain is reported to have said, "lies, damn lies, and statistics!" Statistics are confusing and by trying to keep it simple I erred. But part of the fault lies in how the accidents are reported. Having spent many years reviewing accident reports and analyzing them I can say with assurance that much of the problem lies with how they are reported and coded by the states. That data is then compiled at USCG HQ. I do not envy the statisticians doing the job. I knew them all before I retired. But stats can be interpreted many ways. So it is difficult to make any sense of them some times.

    I am not an advocate of prop guards for every boat or situation. I do believe they are appropriate in some circumstances, house boats being one. In 1996 (or 7?) we held public hearings on this and I was the moderator for about half of them. It was very interesting to hear what everyone had to say. There is no doubt in my mind that this is a problem that needs to be addressed but the real question is not should it be addressed, but how?

    Unfortunately I do not have a solution.

    PS (those hearings were in 86 or 87, not 96, 97. Senior moment)
  6. Submarine Tom

    Submarine Tom Previous Member

    I've been pulling people and property out of the water under adverse conditions for years and never had any prop issues.

    I attribute it to good training and good practices, nothing more.

    If I get something in my prop I'm screwed (no Pun intended).

    I instantly go from a huge asset to a huge liability.

    It's simply not an option and avoidable.
  7. jonr
    Joined: Sep 2008
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    Location: Great Lakes

    jonr Senior Member

    IMO, you are better off with 1) proper skills and caution and 2) a lanyard kill switch.

  8. Ike
    Joined: Apr 2006
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    Location: Washington

    Ike Senior Member

    MIAMI (WSVN) -- A fun day on the water took a dangerous turn.

    A 14-year-old girl and a 5-year-old boy were injured in a boating accident Sunday afternoon in northern Biscayne Bay off the Julia Tuttle Causeway.

    The young girl got caught in the propeller of the boat, after falling off an inner tube.

    Sea Tow and fire rescue workers freed the girl from the propeller. "We were able to get her free," said Brett Sternbach. "Get her aboard my vessel, and take the young lady and the other child that was injured over to Mount Sinai Hospital for them to take care of them."

    The teenage girl suffered deep cuts to her leg.

    (Copyright 2013 by Sunbeam Television Corp. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.)

    There is a video at the link above.
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