Yamaha Possible Coverup of Propeller Guard Documents Exposed

Yamaha Prop Guard Statements

Yamaha Prop Guard Statements

In March 2012 Yamaha announced a new stainless steel propeller guard for outboards on flood rescue boats in the UK and made several statements about how great it was, how well it performed, and even how prop guards were necessary when people were in the water near the boat. About October we became aware of Yamaha’s new propeller guard. In mid October we began posting some materials about it and some of Yamaha’s own statements about their guard.

The boating industry has long defended itself in propeller injury court cases by claiming propeller guards don’t work. Among their objections, the industry claims guards create too much drag, reduce performance (top speed), effect the handling of the boat, are not durable enough, get bent into the propeller, and they create blunt trauma injuries when they strike people.

But Yamaha was making the exact opposite statements about their propeller guard. Yamaha said their guard worked great, minimized drag and performance reduction, improved handling, was strong and durable for use in shallow water, and guards were essential for operating rescue boats near people in the water.

Our mid October 2012 posts echoed several of Yamaha’s own comments.

By early November 2012, everything Yamaha ever said about the propeller guard AND all records of the guard’s existence vanished from their website. We made many attempts to contact Yamaha about why they pulled all of their materials about the propeller guard, but they will not respond. That leaves us to suspect Yamaha erased their statements to protect the boating industry’s long standing legal defense, “Guards don’t work”.

Among the many specific statements made and deleted by Yamaha about their propeller guard were: Read More →

Research Projects for Senior Design Classes, Masters Thesis Projects, Industrial Design & Other Researchers

Most college students in engineering and design take one or more design project classes, often a Senior Capstone Design Projects Class, in which they work individually or as teams to develop solutions to problems. We are trying to tap this resource and encourage students to consider selecting design projects related to propeller safety. More student design projects would help grow the body of knowledge available to the industry and to boaters. In addition to engineering and design students, we also welcome those from all fields and encourage them to consider projects in this area for their capstone classes. If you or others are interested in a college design class project or capstone project in propeller safety, propeller injury avoidance devices, or related fields, please view the projects listed below and contact us for additional assistance.

Propeller Guard

Propeller Guard

A few Masters and Doctoral students have written thesis and dissertations in this field. We strongly encourage Masters and Doctoral students looking for thesis and dissertation topics to contact us and discuss some of the possibilities available in their specific field of interest, as well as those looking for topics for scientific and technical papers.

We list of several possible boating propeller safety research projects below and will be posting more over time. Read More →

Expose on boat propeller accident propels Arizona to action

Every weekend on Lake Pleasant led to a major boating accident for several weeks this summer (2023). Some of these Maracopa County, Arizona accident were boat propeller strikes.

A local media outlet, Arizona’s Family released a great video on November 15th, 2023. The video uses one boat propeller accident as an introduction to talking more broadly about the problem. The video also addresses issues specifically associated with rental boats which are more frequently involved in propeller accidents.

Arizona Family’s report states, “In Arizona, two people died from prop strikes and 60 people suffered boating injuries.”

The YouTube video below issued November 15th.

The video was introduced by print media as Propeller strikes maim or kill recreational Arizona boaters every year.

This video is not just a video to watch and move on. It is a video to propel people to action. Some will take a boating safety class. Viewers will be more aware of their surroundings on a boat. Some rental boat agencies may re-evaluate their training process. Others will share the video with their friends and colleagues.

The Padilla Accident

The video specifically follows the July 22, 2022 incident in which 34 year old Alyssa Padilla was struck by a boat propeller.

Per the video, first responders were about 30 minutes getting to her. Response is often slow on large western lakes due to distance. They also often face difficulty locating novice rental boaters on large lakes.

Once on shore and stabilized she was taken by golf cart to an ambulance, then to a life flight helicopter.

Alyssa speaks out about her life changing injury and notes, “I will never be the same.”

Per the video, Alyssa later learned what happened to her happens a lot here and at other lakes.

Propeller Accident Statistics

The reported notes another woman died last summer. A six year old girl died this year. Both died by propeller strikes on Lake Pleasant.

The reporter states the U.S. Coast Guard reported 173 propeller accidents last year.

The Danger of Boat Propellers

Arizona Family’s reporter went on to say every single one of them was preventable.

Maricopa County Sheriff’s Deputy Detective Rob Marsky officer says the first thing you will hear is, “It happened so fast.”

He noted “propellers are like blenders”. “Even at idle speed a propeller could spin 40 times a second.”

Deputy Marsky stated,”Our victims can bleed out very, very quickly.”

Common Boat Propeller Accident Scenarios

“The number one reason that prop strikes happen is because of operator inattention.”

“One of the most common scenarios is someone is behind the boat, goes to swim toward the boat, and the driver turns the motor on.”

The article points out the boat ladder is often attached to the back of the boat right next to the motor and propeller.

Alyssa Padilla explains that when the boat was started, it created a suction of water into the propeller which was taking her into the propeller.

Propeller Safety Issues Concerning Rental Boats

Joe Watkins represents Alyssa in a lawsuit against Scorpion Bay, the firm that rented the boat. Mr. Watkins says propeller strikes do happen on really disturbing regular basis. He goes on to note they tend to happen to people that are renting boats.

The video goes on to discuss safety briefing issues involving rental boats.

In Alyssa’s instance, the sheriff’s office says the boat rental company did not even have the name of the person that rented the boat.

Deputy Marsky recounts the importance of boat operators receiving boating safety education.

Arizona is one of four states with no requirements for boat operators to receive safety training.

Our Comments

We salute Arizona Family, Alyssa Padilla, Officer Marsky, Joe Watkins, and their production crew. Their work will increase awareness of boat propeller accidents. They also exposed safety issues at some boat rental facilities.

While we can’t thank them enough, we do take issue with three points made in the video:

Point #1. 173 accidents reported by USCG in 2022

The video states, “Last year (2022) across the country the U.S. Coast Guard reported 173 accidents where people were struck by boat propellers.”

They are correct, in 2022 USCG reported 173 incidents in which one or more people were struck by a boat propeller. However, the actual total of individuals struck by a boat propeller reported by USCG in 2022 was 182 injured and 41 fatalities.

In addition, there has long been a tug of war over propeller strike statistics. The boating industry claims almost all propeller injuries are reported and propeller safety advocates argue many propeller accidents are not reported.

Note – the second print version of the article did include the statistics provided above. They were likely left out of the video to shorten it.

Point #2. Even at idle propellers can be rotating at 40 times per second

If an outboard powered boat was idling at 1,000 RPM in gear with a 2 to 1 reduction in the gearcase, the propeller would be turning about 1,000 RPM / 2 = 500 RPM or 8.3 times per second.

Several propeller safety brochures note the number of blades on the propeller is also important. For example even at 8.3 revolutions per second, a three bladed propeller could strike you 25 times per second.

The old U.S. Coast Guard “Beware of Boat Propellers…A Hidden Danger” brochure stated,”A typical three-blade propeller running at 3,200 rpm can inflict 160 impacts in one second.”

Cropped from the U.S. Coast Guard 2007 flyer, "Beware Propellers...A Hidden Danger".

Cropped from the U.S. Coast Guard 2007 flyer, “Beware Propellers…A Hidden Danger”.

Point 3. The reporter said, “Every single one of them was preventable.”

We agree many propeller accidents are preventable or at least can be mitigated. Tools currently available include boating safety education, rental boat safety training, operator attention, use of a spotter, sober boat operator, avoiding or limiting alcohol consumption by all on board, no use of drugs, not going faster than conditions allow, always having a lookout, and keeping your boat in proper condition.

Other existing prevention and mitigation methods include having proper safety equipment onboard, wearing a life jacket, using a kill switch / ECOS lanyard, first aid kits, no bow riding, divers and snorkelers always using dive flags, boat safety inspections, keeping a spare lanyard for use if the operator is ejected, etc. While this is just a partial list, it is easy to see why novice boaters might not cover all these bases, especially in a party environment on a lake they are no familiar with.

Point 3 Part A

Other propeller accidents could be prevented or mitigated with the use of additional safety equipment often not found on board such as VHF radios, GPS, first aid kits on rental boats, tourniquets or something that could be repurposed as a tourniquet on rental boats, indicators showing those in the water when the engine is running and the propeller is turning.

Another safety tool useful on large lakes is an Emergency Position Indicating Radio Beacon (EPIRB).

Point 3 Part B

Still more propeller accidents could be prevented or mitigated by design or equipment not accepted by boating industry manufacturers. Examples include boat propeller guards on slow moving rental boats, increasing distance from the ladder to the propeller, rear view cameras like on cars, removing the front ledge of pontoon boats that attracts bow riders at least on rental boats, using a doorbell switch to force the use of a spotter at the rear of a houseboat while backing up.

Additional designs and equipment not accepted by the boating industry include auto detection and stopping of circling unmanned boats, use of two stage tilt cylinders, use of products of the nature of The Leash”, devices only allowing certain users to pilot rental boats, use of warnings that point out the result if you do not follow them, and Public Service Announcements that graphically illustrate what can happen to you.

Even if most of the protections mentioned above were in place, boat propeller accidents will still occur. Challenges that can place someone in contact with a propeller include severe weather, mechanical failures, kill switch failures, steering failures, medical emergencies, striking submerged objects, hitting a stump, striking a dredge pipe, hitting a rock, becoming grounded and trying to push the boat off a sandbar, becoming entangled in a tow rope, horseplay.

Additional ways propeller accidents will still occur include boater fatigue, wakes generated by large vessels nearby, rogue waves, running over a diver or snorkeler without a dive flag, people swimming in open water, people swimming outside of a swim area, boats capsizing or sinking, other boats running over your boat, solar glare, changing lake levels, and mixed traffic (canoes, kayaks, paddle boards) with larger faster vessels.

And there are multiple paths by which those onboard PWC’s can contact your boat’s propeller.

For a More Complete List of Boat Propeller Accident Scenarios

See our propeller strike scenarios list for a more complete listing.

In Closing

Thanks again to ArizonaFamily for this important video. We hope many people and businesses will be inspired to take action based upon this video. They have a vastly larger and broader audience than us. We thank them for their efforts.

Mercury Pro XS Fatal Flaw video: flipping into boat

“MERCURY PRO XS FATAL FLAW! ARE YOU AT RISK?” video was released on YouTube October 28, 2023.

The video was produced by Team Marine Service, a La Crosse, Wisconsin based marine service & repair business.

It focuses on recently manufactured Mercury Marine Pro XS outboard motors breaking off and flipping into boats.

Andy Houser of TMS discusses several recent accidents in which large Mercury outboard motors broke off and flipped into boats.


The video notes many of the Pro XS outboard motors have broken in exactly the same spot (the swivel bracket).

He appeals to Mercury to let him visit the plant for a sit down visit with them. He would like to be able to ask them, Why is this breaking?”

Suzuki and Yamaha have recently sent representatives to visit with him in La Crosse.

Houser notes the video is not an attack on Mercury. They just want Mercury to recognize the problem, fix it, and let the public know what they need to do to stay safe in their boat.

Houser recognizes outboard motors are abused. He notes that for those running nearby in the Mississippi River “its like a war zone out there.” People hit stuff all the time.

He presents “The Leash” as a means to stay safer at this time.

In efforts to keep his viewers safe, Houser said, “If you are running a Mercury, go get a Leash for me.”

Our Comments

Team Marine Service seems to think this is a recent problem with Mercury Pro XS outboard motors. Our list of large outboard motors breaking off and flipping into boats and our list of all sizes of outboard motors breaking off and flipping into boats show the problem goes back decades.

We previously produced two volumes of methods to prevent or mitigate this problem. Many of them already patented, but not used, by the boating industry.

  1. Approaches to Prevent Outboard Motors From Flipping Into Boats After Striking Floating or Submerged Objects Third edition. 2018.
  2. Approaches to Prevent Outboard Motors From Flipping Into Boats After Striking Floating or Submerged Objects Supplement #1. 7 November 2020.

We also produced:

In closing, a big thanks to Andy Houser and his team at Team Marine Service. Their video will increase awareness of the issue and help save lives.

Monitoring outboard log strikes: Yamaha Patent Application

Yamaha’s U.S. patent application, “Collision Information Providing System, Collision Judging System, and Marine Vessel” was published October 12, 2023.

Yamaha’s system classifies and monitors three different kinds of collisions.

1. Outboard motor / Marine drive collisions

2. Propeller collisions

3. Vessel collisions

These types of collisions are monitored. They are classified. Their intensity is rated. Additional data is recorded.

Collisions are classified by type: marine drive, propeller or vessel collision. (ECU) Engine Control Unit data is monitored and used in the decision making. ECU data used includes engine rpm, throttle setting, air intake pressure, trim position, and shift status (forward, neutral, reverse). The ECU also reports if the shift mechanism is in the process of shifting.

Yamaha refers to struck a log / log strike as a driftwood hit.

Yamaha’s Patent Application

A full copy of Yamaha’s patent application can be found on Google Patents.

The front page of Yamaha’s U.S. Patent Application 2023/0322341 A1 is shown below.

Yamaha log strike monitoring patent application page 1

Yamaha log strike monitoring patent application

Yamaha notes their system applies to all types of marine drives. They specifically list jet boats outboard motors, inboard motors, and inboard outboard motors (stern drives).

Detecting and Classifying the Collision

The first step is detecting a collision by monitoring numerous data sources.

The next step is classifying the collision as being a vessel collision, propeller collision, or driftwood hit (log strike). Unrelated events such as jumping a wake are screened out during the classification process.

Yamaha uses the process outlined in Figure 4 below to classify collisions.

Yamaha outboard motor / marine drive collision monitoring patent application Figure 4: Collision Judging Process

Yamaha outboard motor / marine drive collision monitoring patent application Figure 4: Collision Judging Process

The classification process is described in much greater detail in the patent application. The patent application notes the importance of rejecting other events that might register as a collision. Several such events are listed below.

1. Intentional sudden acceleration of the boat
2. Intentional sudden deceleration of the boat
3. Jumping a wave
4. Engine Cut-Off System (ECOS) / Kill Switch activation
5. Recognizing a propeller has multiple blades and may strike the same object multiple times during a single collision
6. Engine RPM is not stable for a period of time after the engine is started.
7. Intentional throttle position change
8. Low speed and low intensity collisions

Examples of the Classification Process

Some Indicators of a Marine Vessel Hit:

A data table of g acceleration values vs. vessel speed is one of the variables to determine if their was a marine vessel hit.

For example, a value of 1g at speeds of 10 kph or less is an indication a marine vessel hit.

While a value of 24 or more g at speeds of 40 kph or more is an indication a marine vessel hit.

Some Indicators of a Driftwood Hit / Log Strike:

  • Speed must equal or exceed 10 kph.
  • Inclination angle must change by more than 10 percent of the total trim range within 100 ms.
  • After the strike, inclination angle must exceed 120 percent of total trim range within one second.
  • After the event, the drive settles back down.
  • An acceleration sensor on the outboard may directly measure rotational acceleration of the drive.

  • Additional Impact Data Sensors & Sources

    Additional data used in the decision process may include:

    1. Rate of Change of Engine RPM
    2. Video from the time of the incident
    3. Maximum tilt of the drive after the log strike
    4. How fast the drive was tilting
    5. Angular acceleration of the drive from an accelerometer
    6. Status of steering (was the boat in a turn
    7. Marine vessel speed sensor reports speed<"/li">
    8. Engine RPM may be used to estimate speed
    9. GPS location dataGPS may be used to determine boat speed.
    10. Direction of travel of the boat (is it going forward or backward)
    11. Temperature of Engine Cylinder Wall (indication of recent startup)
    12. Audio – sounds including voices on and around the boat at time of collision
    13. Weather

    Missing From the Patent Application

    Noticeably absent from the list of variables is hydraulic tilt cylinder pressure which has been used by others to determine intensity of log strikes.

    Also absent was detecting a quick turn which was suggested by Honda as a means of detecting a near impact. Quick turns in conjunction with some of the other variables may improve impact classification.

    The patent application does not specifically use the phrase “sensor fusion”. However, they do describe using multiple sensors to make a judgement if a collision occurred and what type of collision it was when not all sensors indicate the same result or some sensors may not be present.

    Data Recording and Storage

    Yamaha’s collision judging system stores data. The data is over written every few minutes unless there is a collision. If there is a collision, the collision is classified, and intensity of the collision is judged. Data surrounding the time before and just after the collision is permanently stored and/or transmitted to a remote site.

    Yamaha suggested video could be saved from 30 seconds before the accident through 5 seconds after the accident.

    Boat Rental Applications

    Yamaha’s patent mentions their collision monitoring device has special application to the boat rental market. Marinas could check the system for any impacts when the boat comes back in after a rental. The system could wirelessly report to the marina. In addition, Yamaha’s collision system can estimate damage to the propeller after a collision.

    Similarly, the system could be used by individuals who loan out or charter their boat. When the boat comes back they can check it’s status. They could even monitor their boat in real time.

    While not specifically mentioned, they system could also be applicable to larger sailboats.

    Outboard motor / marine drive collisions

    Outboard motor trim and tilt ranges

    Outboard motor trim and tilt ranges

    The system appears to classify medium intensity log strikes as opposed to catastrophic log strikes. Their highest impact rating goes is awarded when the drive flips up an additional 120 percent of the normal trim range. As we understand it, that means a flip up of 120 percent of 15 degrees in addition to the trim at time of impact. If the drive was trimmed up 7 degrees, their highest impact rating would be given for the drive flipping up another 1.2 X 15 degrees. Or reaching a trim/tilt of a total of 7 degrees plus 18 degrees = 25 degrees.

    Catastrophic strikes bring the outboard on up toward maximum tilt. In some instances outboard motors can break off after maximum tilt and flip into the boat. The engine may still be running as is the propeller.

    Some drives break off before the drive clears the object. In that event, the failure would be obvious and would not need to be recorded.

    Marine drives that are unable to clear the object or take an abnormal time to clear the object might not be classified as driftwood hits.

    Judging Driftwood Hits / Log Strikes

    Yamaha reveals a system in Figure 5 in which they use the rate of change of trim, along with the maximum change in trim/tilt to judge or rate the intensity of a log strike.

    Yamaha outboard motor / marine drive impact intensity scoring system

    Yamaha outboard motor / marine drive impact intensity scoring system

    System Cost

    The full system could require additional sensors, computing power, and a data storage system.

    Yamaha notes “All of the data used in the above-described detection of the occurrence of the propeller hit performed by the ECU is able to be obtained by the existing sensors, etc. of the outboard motor. Therefore it is not necessary to add any additional sensors, etc. in order to perform the detection of the occurrence of the propeller hit, and it is possible to suppress the cost.”

    While Yamaha does not mention it, this system could also be useful in detecting and recording human propeller strikes. One problem however, could be some propeller accidents occur shortly after the engine is started. Yamaha’s system does not detect propeller strikes till the engine cylinder walls warm up and engine RPM becomes more stable.


    Patentability is determined by patent examiners at the U.S. Patent Office. Several systems in this category (monitoring / recording log strikes) have already shown up in the patent system. We even suggested one ourselves.

    We note Yamaha cites two of their previous Japanese Patents related to this invention. Thus, we may see one or more additional U.S. Patent Applications related to this device. Sometimes manufacturers use one patent to protect the methods used by the device and another patent to protect the device itself.

    Related patents and inventions include

    • Suzuki Japanese Patent JP5810881 (B2) – 2015-11-11. “Device, Method and Program for Controlling Collision of Outboard Motor”. Suzuki records tilt vs rate of change of tilt during impacts. See Approaches to Prevent Outboard Motors From Flipping Into Boats pages 167-169. Note the invention is incorrectly attributed to Yamaha in that publication. It is a Suzuki invention.

    • Brunswick: Brunswick filed separate system and method patents for detecting and recording marine drive impacts including their severity. Both patents determine an underwater impact occurred and its severity by monitoring the rate of change of trim and comparing rate of change to a stored value. See Approaches to Prevent Outboard Motors From Flipping Into Boats: Supplement 1 pages 52-54.
      1. U.S. Patent 10,214,271 Systems and Methods for Monitoring Underwater Impacts to Marine Propulsion Devices. Issued 26 February 2019. This patent has the METHOD claims.
      2. U.S. Patent 10,577,068 Systems and Methods for Monitoring Underwater Impacts to Marine Propulsion Devices. Issued 3 March 2020. This patent has the SYSTEM claims.

    • Honda was issued two patents for a marine drive impact recording system. See Approaches to Prevent Outboard Motors From Flipping Into Boats: Supplement 1 pages 57-60.
      1. U.S. Patent 10,272,977 Boat Navigation Assist System, and Navigation Assist Apparatus and Server of the System. Issued 30 April 2019.
      2. U.S. Patent 10,746,552 Boat Navigation Assist System, and Navigation Assist Apparatus and Server of the System. Issued 18 August 2020.

    The Leash Saves Bass Angler From Outboard Motor

    A bass angler was fishing on Santee Cooper Lake in South Carolina. His Mercury Pro XS outboard motor struck a floating log at about 55 miles per hour.

    The outboard motor broke off at the swivel bracket during the October 2023 accident. Several large Mercury outboard motor swivel brackets have failed, allowing the outboard to flip into the boat.

    The Leash is available from Precision Sonar. The Leash prevented this bass fisherman’s Mercury outboard from entering his Ranger boat and killing or maiming him.

    Mercury Marine Pro XS outboard motor broke off Ranger boat and was restrained from flipping into the boat by The Leash

    Mercury Marine Pro XS outboard motor broke off Ranger boat and was restrained from flipping into the boat by The Leash

    This swivel bracket broke horizontally across the top near the serial number tag, as seen below.
    The Leash is in the lower part of the image. Part of The Leash’s cover came off during the accident (see the brown rope-like color).

    Mercury Marine Pro XS outboard motor swivel bracket broke in Santee Cooper log strike

    Mercury Marine Pro XS outboard motor swivel bracket broke in Santee Cooper log strike

    This bass fisherman used his trolling motor to get back to the boat landing and lived to fish another day.

    See this Precision Sonar Facebook post for additional photos and details on this accident.

    More Information on The Leash

    More information and several great photos are available from Precision Sonar’s Facebook Page.

    The image below shows two Mercury outboards with The Leash installed. Other methods of installation are now available.

    The Leash: left and right views side by side

    The Leash: left and right views side by side

    Rex Chambers and his fishing partner were injured in 2014 when they struck a submerged log. The 250 horsepower Mercury outboard motor broke off, and flipped into the boat still under power.

    Rex later posted a video on his Facebook page about The Leash.

    We liked his down home, straight forward talk and how he is able to speak from personal experience of the need to tether large outboard motors. He has since passed on, but was and continues to be bass fishing great.

    Honda Air Bag Propeller Guard Patent Application

    Honda Motor Co of Japan filed a U.S. patent application for a propeller guard partially consisting of an air bag
    The patent application, US 2023/0278686 A1 “Outboard Motor Control Apparatus and Control Method for Outboard Motor” was published by the U.S. Patent and Trademark Office on September 7, 2023.

    Honda’s patent application has to do with preventing propeller contact with objects or people behind the vessel. It also focuses on preventing objects from winding up on the propeller. This post will focus on Honda’s efforts to prevent people from being stuck by a propeller while behind a boat.

    An image of the device is shown below:

    Honda air bag propeller guard patent drawing

    Honda air bag propeller guard patent drawing

    The device consists of a soft, elastic rearward protrusion from the propeller containing an airbag.

    How Honda’s Airbag Propeller Guard Works

    First, please note Honda does not refer to this invention as a propeller guard. They call it an “Outboard Motor Control Apparatus and Control Method for Outboard Motor”.

    If someone contacts the soft, elastic protrusion behind the propeller, it mitigates their impact. Then the resistance to rotation begins to slow the rotational speed of the propeller. Or, it begins to slow the acceleration of the rotational speed of the propeller. Thresholds are determined and programed into the Engine Control Unit (ECU). This slowing or rate of slowing can also be used to determine if it is a person or not. The system can affirm a person is there via infrared sensors or a camera.

    An alarm can be sounded depending on what is in contact with the protrusion behind the propeller.

    If it is a human, priority can be assigned to this finding. Propeller rotation can be quickly stopped and an air bag can be inflated to push the human away from the propeller.

    The air bag can also slow the human down if they were rapidly approaching the propeller.

    The Diagram below shows how the system basically works.
    Note the power system is referred to as “the prime mover” leaving room to cover fossil fuel engines, battery powered outboards, or other prime movers.

    Honda air bag propeller guard diagram patent drawing

    Honda air bag propeller guard diagram patent drawing

    The Logic System

    The basic logic used by the ECU to make decisions surrounding this propeller guard or virtual propeller guard is shown below.

    Honda air bag propeller guard logic map patent drawing

    Honda air bag propeller guard logic map patent drawing

    Other Features

    The patent application speaks of urgently stopping the rotation of the propeller. However it does not elaborate on how that will be done.

    The soft, elastic protrusion containing the airbag can be detached from the propeller. This makes it easily installable for specific applications. No specific applications are listed. Some potential outboard powered boat applications that come to mind are:

    • skiing and tubing
    • rental houseboats
    • rental pontoon boats
    • dive boats
    • boats used in “raft ups”
    • youth sailing coach boats
    • rescue boats and flood rescue boats
    • Some might suggest their use on outboard motor powered boats during wake surfing. That is a debate for another time
    • military applications
    • protecting commercial diver airlines from the propeller
    • military minesweeper arrays on the surface of the water, towed by helicopters use very expensive cables that might be protected by this device

    Even More Features

    Honda’s patent application describes an emergency button on the outboard motor at a location that could be triggered by swimmers that feel they are in danger.

    Most outboard motors are used with through prop exhaust. This patent application does not explain the details of that feature.
    There may be additional patent applications coming with greater details on certain elements of this invention.

    Automotive airbags and refilling them can be very expensive. Many boaters are used to more economical cartridges used to inflate life jackets. No mention is made of the cost of Honda’s approach.

    The system is adaptable to boats powered by multiple outboard motors.

    Mechanics of Filing This Patent Application

    Honda Motor first filed a patent application in Japan on December 28, 2021.

    Almost a year later, they filed the U.S. patent application on December 13, 2022.

    The U.S. Patent Application was published September 7, 2023.

    Our Comments

    We salute Honda Motor for thinking outside of the box and placing one more approach to boat propeller safety in the literature.

    We hope Honda is able to bring this device to market and generate more interest in this field.

    Malibu Boats Safety Alert: Bow Seating Hazard

    Malibu Boats released a Safety Alert regarding a Bow Seating Hazard on July 18, 2023.

    Malibu reports the safety alert is due to a tragic incident that occurred with a Malibu Response LX boat. A passenger was washed out of the bow seating during a bow swamping incident. The passenger was then hit by the propeller and died.

    2000 Malibu Response LX Courtesy

    2000 Malibu Response LX

    To prevent this from occurring again, Malibu now prohibits passengers in the bow of similar boats, while the boat is in motion. They will provide updated capacity labels and warning stickers reflecting this new safety policy.

    The Safety Alert identifies specific Sunsetter, Mystere, Echelon, Response, and Sportster models and years subject to this change.

    Malibu Boats notes their commitment to safety. “We sincerely regret that a Malibu branded boat was involved in such a tragic accident. Malibu is committed to the continuous improvement and safety of watercraft.”

    In closing Malibu notes they understand reducing your boat’s seating capacity is an inconvenience, and apologizes for doing so.

    The Safety Alert

    Malibu’s Safety Alert is available in pdf format from a link at the top of this post. The Safety Alert is also available in the images below:

    Malibu Boats Safety Alert: Bow Seating Hazard Page 1

    Malibu Boats Safety Alert: Bow Seating Hazard Page 1

    Malibu Boats Safety Alert: Bow Seating Hazard Page 2

    Malibu Boats Safety Alert: Bow Seating Hazard Page 2

    Malibu Boats Safety Alert: Bow Seating Hazard Page 3

    Malibu Boats Safety Alert: Bow Seating Hazard Page 3

    Malibu Boats Dealer Version of the Safety Alert

    As is often done in situations like this, Malibu prepared a Service Advisory version of the Safety Alert specifically for their dealers. The Dealer Service Advisory conveys similar information in abbreviated form. It also tells them to provide the following instruction to owners of these specific boats. “DO NOT allow passengers in the bow area while in motion.”

    Malibu Boats Dealer Service Advisory

    Malibu Boats Dealer Service Advisory: Bow Seating Hazard

    Our Comments on Malibu’s Safety Alert

    We posted our comments on Malibu’s Safety Alert on a separate post, Comments on Malibu Boats Safety Alert : Bow Seating.

    Comments on Malibu Boats Safety Alert : Bow Seating

    Malibu Boats released a Safety Alert in July 2023 regarding bow seating and swamping in certain older Malibu boats.

    This post will discuss the history behind Malibu’s bow swamping Safety Alert, comments concerning the Safety Alert, and possible future implications.

    Background History

    Long ago, some ski boat manufacturers began to offer open bow boats with seating in the bow. Some were referred to as “hot tubs” because the bow was closed in from behind by the helm. To get between bow seating and the main seating of the boat, you had to open the windshield and crawl over the helm.

    See the Malibu Response LX image below:

    2000 Malibu Response LX Courtesy

    2000 Malibu Response LX

    As early as 1994, rec.sports.waterski on UseNet (pre modern Internet forums) discussed the safety of children in the open bow of ski boats. See “Open vs. Closed bow” John A. Knapp. 13 November 1994.

    Ski boats turned to downward sloping bows and low freeboard (distance from gunnel to the water). This allows the operator to see over the bow a little better during takeoff. It also provides an aesthetic side view of the vessel. However, these features make it easier to take water over the bow and experience bow swamping.

    The Mastercraft Accident

    July 9, 2006, Bethany Mercer (then Bethany Wallenburg) and Niki Bell were on Lake Oroville (California) in a MasterCraft X-45 wake board boat. Both women were in the open bow. They were both washed out, and very severely struck by the propeller.

    This accident grew into a legal case, Robert Bell vs. MasterCraft Company. Much of the case focused on the design of the boat. However, the accident originated with the two women being washed from the bow, and ended with them both being struck by the propeller.

    MasterCraft X45 boat

    MasterCraft X45 boat

    The jury rendered a $31.4 million verdict on June 7th, 2011.

    The towboat industry immediately went into a fury developing warnings for their boats and operators manuals regarding open bows and bow swamping. These new warnings typically limited the open bow capacity to “X” pounds and/or required an adult in the bow if children were present, and/or limited bow capacity to “Y” individuals.

    The Incident

    Malibu Boats says a tragic incident involving A Malibu Response LX boat triggered this bow seating Safety Alert. They further identify the boat as a 2000 Malibu Response LX boat.

    I do not recall previously seeing a Safety Alert / Service Bulletin / or Product Recall being attributed to one specific accident.

    While not stated in the Safety Alert, the incident cited is obviously the 17 July 2014 Georgia accident in which 7 year old Ryan Batchelder was killed. The accident resulted in a legal case, Batchelder vs. Malibu Boats. On 28 May 2021 the judge issued a $200 million verdict against Malibu. On 30 June 2023, Malibu reached a settlement to pay $100 million.

    Eighteen days later, Malibu released this Safety Alert.

    Malibu Boats West, Inc.

    In the Batchelder case, Malibu Boats LLC expended great effort to prove they had nothing to do with boats designed and manufactured by Malibu West. However, the jury did not agree.

    It seems a bit unusual that Malibu Boats LLC is still trying to make that claim in this Safety Alert (see image clips from the Safety Alert below). What entity built the boat seems of little interest to those receiving the Safety Alert.

    Malibu Boats Safety Alert clip 1

    Malibu Boats Safety Alert clip 1

    Malibu Boats Safety Alert clip 2

    Malibu Boats Safety Alert clip 2

    Authority to Issue the Safety Alert

    Malibu Boats LLC is saying they did not design or manufacture these boats and have nothing to do with them other than purchasing some assets from Malibu West in 2006. If so, it seems odd Malibu Boats LLC is able to issue Safety Alerts pertaining to these vessels and tell current owners no one can be in the open bow while underway.

    It is almost as if they could issue a Safety Alert for certain Brunswick boats and place some limitations upon their use.

    Increasing Awareness of the Safety Alert

    Malibu Boats has long had a major internet presence. They have a website, multiple social media outlets as well as independent forums such as The Malibu Crew. I found no mention by Malibu of this Safety Alert on their various social media platforms. Malibu boater owners on The Malibu Crew were left to speculate about what the the Safety Alert said, and which vessels it applied to. A great opportunity to contact existing owners through these numerous outlets was missed.

    The URL provided on the Safety Alert itself ( leads to a web page requesting your information and your knowledge of the most current owner of the boat. It also contains a link to the actual Safety Alert as seen the image below.

    Malibu Safe Boating page requesting your contact information and information on your boat.

    Malibu Safe Boating page requesting your contact information and information on your boat

    While the above page is on Malibu’s website. There is no way to see it or find it unless you know it exists.

    Malibu Boat’s Commitment to Safety

    Malibu closes their Safety Alert confirming their commitment to safety.

    Malibu Safety Alert clip 3, their commitment to safety

    Malibu Safety Alert clip 3, their commitment to safety

    Malibu Boat’s commitment to safety (above) seems a bit challenging to resolve in this specific instance to resolve with:

    1. Malibu taking 9 years to publish this Safety Alert (accident in 2014, Safety Alert published in 2023).
    2. At the conclusion of the Batchelder trial, Malibu requested a new trial. The judge issued an order rejecting Malibu’s request on July 18, 2022. The following statement, written by the judge, comes from that order.
    3. “Compelling evidence established that Malibu made repeated conscious decisions to not warn of a known safety defect, it mocked customers who attempted to raise concerns about bow swamping, it decided to warn about the risks of bow swamping on new boats, including the Response LX, while refusing to warn on identical boats it had already sold, despite knowing that the swamping risk posed the life-threatening hazard of “washing a small child from the bow.””

    4. There were numerous other bow swamping events involving the vessels listed over this time period. One of the most notable being the Kreush accident which claimed the life of a four year old boy. The specific vessel in that instance was a 2004 Malibu Response LXi open bow ski boat. See news clip below.
    5. Kreusch fatal boat bow swamping accident involving a Malibu LXi boat built in 2004

      Kreusch fatal boat bow swamping accident involving a Malibu LXi boat built in 2004

      Per the Ohio Department of Natural Resources boat accident report, the boy in the Kreusch accident was wearing a life jacket and entrapped in the boat propeller, as was Ryan Batchelder 7 years later.

    Post Sale Monitoring Product Safety

    We provide free, extensive post sale safety monitoring training materials. They can help boat builders and marine drive manufacturers desiring to monitor the safety of their products in the field.

  • Post Sale monitoring boats for safety hazards: Introduction to our coverage
  • BARD Boating Accident Report Database Training: Index”
  • BARD Training Videos

  • The Future

    One wonders if the Batchelder lawsuit and this action by Malibu will cause another ripple through the industry like the MasterCraft accident. We may see a new interest in bow riding warnings and warning labels on these older vessels and newer vessels as well.

    Walter Greer, 3, killed by boat propeller in Utah

    Walter Greer, age 3

    Walter Greer, age 3

    Walter Greer, age 3 from Salt Lake City, was on a wakeboard boat with his family. They were on Echo Reservoir northwest of Coalville (Utah) Sunday, August 13, 2023.

    About 4:45pm Walter Greer fell from the wakeboard boat. Walter was fatally struck by the boat propeller.

    Walter was wearing a life jacket when he fell overboard and when his body was recovered.

    The young boy liked Spiderman, trucks, boots, and trains.

    The Boat & Official Comments

    Utah Division of State Parks representative Devan Chavez said the family was water skiing behind a wakeboard style boat at the time of the accident.

    Wakeboard boat in Walter Greer fatal boat propeller accident at Echo Reservoir, Utah.

    Wake board boat in Walter Greer boat propeller accident on Echo Reservoir.

    The open bow wakeboard boat appears to be a Pickle Fork design. It is a little broader at the front of the bow than traditional wakeboard boats.

    Park Rangers recovered the young boy’s body. Authorities pronounced Walter Greer dead at the scene.

    Police do not suspect foul play or DUI, and report it was just “an unfortunate and tragic accident.”

    Agencies Responding

    Agencies responding to the accident included:

    • Utah State Parks
    • Utah State Bureau of Investigation
    • Summit County Sheriff’s Office
    • Utah Highway Patrol
    • North Summit Flyer District
    • University of Utah Health AirMed
    • Utah Division of Outdoor Recreation

    A GoFundMe page for Walter Enslin Greer identified Walter’s parents as Alex and Doug.

    How Did The Accident Happen?

    Few details other than it being a wakeboard style boat have been provided thus far.

    As is typically the case, many online comments are highly critical of the family. They jump to all kinds of negative conclusions with few details provided.

    We will join in the speculation.

    The Details / Facts

    About the only details are:

    1. The boy was on the wakeboard boat with his family. No total number of people is provided. However, it was him, his parents, his two older sisters, and another family.

    2. The boy was wearing a life jacket.

    3. No obvious DUI issues.

    4. Walter Greer was fatally struck by the propeller at what news report call “the back of the boat”. Comment – this is an inboard powered boat. The propeller is back up under the sun deck and the transom a ways.

    5. Most reports say Walter was obviously dead when his body was retrieved from the water by a Park Ranger. A few reports say lifesaving attempts were made. They said the recovery of Walter Greer’s body was not difficult and they did not have to search for it.

    6. The wakeboard boat had an open bow per the photograph.

    7. A spokesperson for Utah Division of State Parks said they were water skiing at the time of the accident.

    8. Walter Greer was 3 years old.

    9. It is quite normal for early facts surrounding an accident to be in error.

    One Possible Conclusion

    NOTE- this possible conclusion is pure speculation made on unverified facts.

    Given the details above, it “sounds like” the young boy likely fell into the water somewhere over the gunnel forward of the rear half of the boat. If he had fallen overboard near the stern and they were actually water skiing (in a straight line), it is a challenging to envision him being pulled into the propeller. If they were wakeboarding it becomes more possible to be pulled into the propeller from the back half of the boat. This is due to the back of the boat typically being very deep into the water and the propeller pulling very hard at a slower speeds than water skiing.

    Walter Greer probably did not fall overboard in the area of the seats right behind the windshield unless he was being held and was somehow released. But he looks like a large boy to be being held.

    That leaves the open bow or the area behind the operators seat on back to about the midpoint of the boat.

    His body wearing a life jacket and not being retrieved from the water til a Park Ranger arrived leads one to believe he may have been entrapped on the propeller or it may have been a catastropic propeller strike.

    We anticipate more information may be forthcoming.

    Malibu Boats agrees to pay $100 million in Batchelder case

    A 2014 propeller strike in Georgia claimed the life of 7 year old Ryan Batchelder.

    In August 2021 Malibu Boats was found guilty in Superior Court of Rabun County Georgia. The Product Liability Case verdict totaled $200 million dollars.

    Since then, Malibu Boats has been trying to reduce or eliminate the jury award.

    Malibu Boats, Inc filed a Form 8-K with the Security and Exchange Commission dated June 30, 2023. 8-K forms are use to report significant events to shareholders.

    The 8-K report announces Malibu Boats Inc and its subsidiary, Malibu Boats LLC have reached a settlement agreement with the Batchelder family in the legal case. Per the agreement, Malibu Boats will pay the Plaintiffs (the family of Ryan Batchelder) $100 million to finally end this product liability case.

    Malibu will immediately pay $40 million. $60 million will be placed in escrow to be released to the Plaintiffs upon satisfaction of certain conditions.

    The Product Liability Case focused on several aspects beyond just the propeller accident, including:

    • Product design
    • Product testing
    • Warnings
    • Taking water over the bow

    However this is obviously the largest verdict / award ever made in a boat propeller accident.

    2000 Malibu Response LX Courtesy

    example of a 2000 Malibu Response LX

    The Actual Announcement in Malibu Boats’ 8-K Report

    Item 1.01. Entry into a Material Definitive Agreement.

    As previously disclosed, Malibu Boats, Inc. (the “Company”) and its indirect wholly owned subsidiary, Malibu Boats, LLC (“Boats LLC”), are defendants in
    the product liability case Batchelder et al. v. Malibu Boats, LLC, f/k/a Malibu Boats, Inc.; Malibu Boats West, Inc., et. al., Superior Court of Rabun County,
    Georgia, Civil Action Case No. 2016-CV-0114-C (the “Batchelder I Matter”) and Boats LLC is also a defendant in a related product liability case, Stephan Paul
    Batchelder and Margaret Mary Batchelder, as Natural Guardians of Josh Patrick Batchelder, a minor; Darin Batchelder, individually, and as Natural Guardian
    of Zach Batchelder, a minor; and Kayla Batchelder v. Malibu Boats, LLC v. Dennis Michael Ficarra; State Court of Rabun County, Civil Action File No. 2022-
    CV-0034 (the “Batchelder II Matter,” and together with the Batchelder I Matter, the “Batchelder Matters”). The Batchelder Matters involved a personal injury
    accident in 2014 involving a 2000 model year Response LX boat that was manufactured by Malibu Boats West, Inc. (“West”). West is not, and has never been,
    a subsidiary of the Company but was a separate legal entity whose assets were purchased by Boats LLC in 2006.

    The Agreement

    On June 30, 2023, the Company and Boats LLC entered into a Confidential General Release and Settlement Agreement (the “Settlement Agreement”), by and
    among each of the plaintiffs in the Batchelder I Matter (the “Batchelder I Plaintiffs”) and the plaintiffs in the Batchelder II Matter (“the Batchelder II Plaintiffs,
    and together with the Batchelder I Plaintiffs, the “Batchelder Plaintiffs”) in settlement of each of the Batchelder Matters. The Settlement Agreement provides
    that, among other things, the Company, or Boats LLC, as the case may be, will pay (or cause to be paid) to the Batchelder Plaintiffs and their agents a total of
    $100.0 million, of which (a) $40.0 million will be paid to the Batchelder Plaintiffs and their agents promptly following the execution of the Batchelder
    Agreements and (b) $60.0 million will be placed in an escrow account and held by the Escrow Agent pursuant to the terms of an Escrow Agreement, which
    amount will be released to the Batchelder Plaintiffs and their agents upon the satisfaction of certain conditions, as further described in the Settlement

    The foregoing description of the Settlement Agreement is a summary and is qualified in its entirety by reference to the full text of the Settlement Agreement,
    which is attached hereto as Exhibit 10.1, and such exhibit is incorporated herein by reference.

    Item 2.02 Results and Operations and Financial Condition

    As of July 3, 2023, the Company reaffirms its previously announced guidance for fiscal year 2023 net sales and Adjusted EBITDA margin. For fiscal year
    2023, the Company anticipates net sales growth slightly over 10% year-over-year and Adjusted EBITDA margin down slightly year-over-year. The Company
    expects to incur the full $100.0 million related to the settlement of the Batchelder Matters as a charge to net income for the fourth quarter of 2023. The
    Company expects that all amounts paid by it with respect to the settlement of the Batchelder Matters should be tax deductible for federal and state income tax
    purposes. The litigation settlement expense related to the Batchelder Matters will be excluded from net income in arriving at Adjusted EBITDA. See “NonGAAP Financial Measures” below for more information regarding Adjusted EBITDA.

    Item 8.01 Other Events

    Insurance Litigation

    The Company and its subsidiaries, including Boats LLC, maintain liability insurance applicable to the Batchelder Matters.

    On July 3, 2023, Boats LLC filed a complaint against Federal Insurance Company and Starr Indemnity & Liability Company alleging that the insurers
    unreasonably failed to comply with their obligations by refusing, negligently and in bad faith, to settle covered claims within their available policy limits prior
    to trial. The Company intends to vigorously pursue its claims against its insurers to recover the full settlement amount (less any monies already tendered
    without reservation by the carriers). However, the Company cannot predict the outcome of such litigation.

    Expected Borrowing under Revolving Credit Facility

    On July 3, 2023, Boats LLC, an indirect subsidiary of the Company, notified its lenders that it intends to borrow $75.0 million under its revolving credit facility governed by the Third Amended and Restated Credit Agreement.

    Malibu Boat’s Full SEC 8-K Report

    The remainder of their SEC report provides the in-depth details of the settlement and of the conditions needed to release the escrow funds. It shows how much of the funds will be paid on a monthly basis to various individuals over a number of years.

    The full report is available at: Malibu Boats SEC 9-K Filing 30 June 2023.

    Boat Propeller Guard Product Liability Defense Intro Vol1

    In the mid to late 1980’s Mercury Marine, a Brunswick Corporation, and Outboard Marine Corporation (OMC) were facing a large number of boat propeller guard product liability / product defect lawsuits. Several of those lawsuits related to kill switches not being installed.

    This post is the second of a series of five posts announcing the materials we prepared on 3 studies performed by the boating industry. These 3 studies are currently used as their legal defense against boat propeller guard product liability / product defect cases.

    This post is a brief introduction to a large four volume pdf report titled Mercury Marine & Outboard Marine Corp. Propeller Guard Case Legal Defense that can be found at Boat Propeller Guard Product Liability Defense.

    Volume I: The Introduction post

    U.S. Coast Guard emblem

    USCG Purcell & Lincoln Boat Propeller Guard Study

    The U.S. Coast Guard published their own, in house, propeller guard study by Edward S. Purcell and Walter B. Lincoln in 1987.

    The study was conducted by reviewing the existing literature on boat propeller guards.

    Purcell and Lincoln’s study was viewed as inconclusive by the Coast Guard in part because Purcell and Lincoln reported:

    1. They needed accurate propeller strike data
    2. Biomechanical testing would need to be performed
    3. Mechanical studies would need to be conducted
    4. Test for severity would need to be conducted
    5. Potential solutions would need to be ranked
    6. Acceptable solutions would need to be identified
    7. Validation testing would need to be performed

    The Efficacy / Effectiveness of Boat Propeller Guards

    From 1988 thru 1990 Mercury Marine and Outboard Marine Corporation (OMC), were involved in three propeller guard studies.

    Once completed those studies were quickly used in court to defend the boating industry’s position against the use of boat propeller guards / prop guards.

    Individuals involved in those studies were used as expert witnesses. They explained the results / recommendations of the studies and how they were derived.

    Each of the three studies: the 1989 NBSAC study, the SUNY underwater head impact study, and the SUNY underwater leg impact study are briefly critiqued below.

    The U.S. Coast Guard 1989 National Boating Safety Advisory Council Propeller Guard Subcommittee Report

    In 1988 U.S. Coast Guard National Boating Safety Advisory Council (NBSAC) formed a subcommittee to study boat propeller guards.

    Mercury Marine and Outboard Marine Corporation (OMC) both had representatives on this subcommittee. It was composed of 4 to 7 members of the 21 members of NBSAC. Mercury was represented by their corporate lawyer, Roy Montgomery.

    NBSAC’s subcommittee report noted, “Several lawsuits involving tens of millions of dollars have been brought to court in the past two years and have heightened interest in this subject substantially.”

    The NBSAC study consisted of a review of the existing literature plus presentations by interested parties.

    The study said blunt trauma from impacting a propeller guard at speed was worse than impacting an open propeller. (no proof was provided, see discussion in head impact study section below)

    Pages 4 and 5 of the NBSAC study lists three legal theories advanced by propeller guard advocates. Pages 5 and 6 along with pages 20 through 22 rebut the use of propeller guards.

    Findings of the 1989 NBSAC Report

    The NBSAC report states, “Presentations illustrated that approximately 80 percent of all accidents occur when a boat is operating at speeds in excess of 10 miles per hour.” This is one of several examples of the subcommittee taking statements made by the industry as being factual. (see pie chart on our Chart #9 which shows this statement is not be true). A variant of this comment is repeated on page 17 as, “It was repeatedly stated that a skull impact of 10 mph or more in the water would generally be fatal.” Just because a statement was presented or repeatedly stated by the industry, does not make it true.

    In November 1989, NBSAC’s propeller guard subcommittee released its final report. The first recommendation was, “The U.S. Coast Guard should take no regulatory action to require propeller guards.”

    This finding was in sharp contrast to USCG’s own 1987 Purcell and Lincoln study. Purcell and Lincoln found much more information needed to be gathered before such a decision could be reached.

    Contributions of Dick Snyder of Mercury Marine to the NBSAC Report

    Richard Snyder of Mercury Marine was not a member of the NBSAC subcommittee on propeller guards. However, several of his statements made it into the final report. Mr. Snyder was known for repeating certain statements about propeller guards over and over to the media and the industry. We refer to those statements as “Snyderisms”. One of Mr. Snyder’s statements making the final report was, “Due to its revolutions, a propeller generally produces a series of evenly spaced cuts which are relatively easier to repair surgically.” Mr. Snyder’s comment ignores several factors including bleeding to death, water born wound infection issues, amputations, the cost and challenges of prosthetics, and many surgeries being required to repair these injuries.

    Another problems with the 1989 NBSAC study, was Mercury Marine knowingly supplied the propeller guard subcommittee with incorrect propeller strike data. This made the problem look much less severe than it actually was. Our report proves this repeatedly using the industry’s own documents.

    The Coast Guard records accidents as a series of three events. Mr. Snyder of Mercury only reported First Event data, also known as Primary Event data. First Event data only represents a fraction of the total number of fatalities recorded in the annual U.S. Coast Guard Boating Accident Report Database (BARD).

    Then Mr. Snyder subtracted 1/3 of the Primary Event accidents saying they were primarily struck by a boat vs by the propeller. Two previous USCG studies were unable to identify a single accident in which the boat was responsible for the most severe injury.

    Next Mr. Snyder subtracted those accidents in which someone was struck by a propeller and drowned. Some of those individuals likely bled out and then drowned or were unable to swim due to the propeller strike.

    Snyder Contributions Continued

    Mr. Snyder also failed to follow the admonition of Purcell and Lincoln. They called for including propeller injury accident data along with the fatality data. Purcell and Lincoln said that in many instances, the only difference in a propeller injury accident and a propeller fatality is chance. Therefore injury accidents must be included in the analysis of propeller accidents.

    USCG Definition of Primary Accident Type

    USCG Definition of Primary Accident Type

    The 1989 NBSAC study also focused on the increased forward facing cross sectional area of the propeller guard vs. the open propeller. When combined with their statements of propeller guard strikes being worse than open propeller strikes, this increase in cross sectional area, portrayed propeller guards / prop guards as being even worse. The claim is humorous today in view of the boating industry featuring countless boats with 3,4, or even more very large outboard motors on them. Multiple large outboards have many times more cross sectional area than added by a propeller guard on a boat powered by a single outboard motor available in 1989.

    The 1989 report even says a propeller guard increases the cross sectional area of an open propeller by 3 times (300 percent). That is an example of the exaggerated claims made by the 1989 NBSAC report.

    The 1990 Underwater Head Impact Study

    A very large donut shaped water tank the State University of New York (SUNY) at Buffalo with a long rotating arm was used for the research project. Michael Scott was hired by Mercury and OMC’s legal departments as the lead researcher of the project. The project was to simulate propeller guard underwater impacts with a human head by using a crash dummy.

    Mr. Scott admitted the NBSAC report’s reliance upon blunt trauma to reject the use of boat propeller guards was not supported by experimental data.

    Scott’s research was to gather data to support the NBSAC study.

    The SUNY head impact study had a lengthy list of problems. Among the most widely known problems being the spring in the crash dummy’s neck was several times stiffer than a human neck in compression. As the propeller guard traversed the dummy’s head it pushed the neck down. This resulted in much high stresses being recorded in the dummy’s neck than would be present in a human neck.

    Scott mentioned the neck stiffness problem in early versions of the report. However all mention of neck stiffness issues was missing from the final version of the report.

    The outboard motor was placed at zero trim (vertical leading edge) which makes it more difficult for a head to slid down the leading edge of the drive.

    The outboard was also configured in a way that made the hydraulic system “stiffer” and eliminated some give in the system that could have reduced peak loads.

    The head impact study even cites Event 1 statistics, years after the industry was aware this was improper.

    The 1990 Underwater Leg Impact Study

    Tyler Kress was hired by Mercury and OMC’s legal department as the lead researcher for the leg impact study at SUNY.

    This study was conducted in the tank at SUNY in conjunction with the head impact study.

    The leg impact study had a lengthy list of problems as well. One of of the most widely known problems was the use of legs from cadavers that were over 70 years old that had been embalmed for several years.

    In addition the legs were impacted perpendicular to the path of the outboard motor (laid horizontally across its path). Most propeller strike leg injuries occur with the person longitudinally coming at the propeller. Such as a swimmer approaching or retreating from the propeller, or legs being in a vertical position near the propeller at the swim ladder.

    The outboard motor was placed at zero trim (vertical leading edge). This makes it more difficult for legs to slid down the leading edge of the drive.

    The outboard was also configured in a way that made the hydraulic system “stiffer”. This eliminated some give in the system that could have reduced peak loads.

    The leg impact study even cites Event 1 statistics, years after the industry was aware this was improper.

    The 1990’s

    As mentioned earlier the industry quickly began to use these studies and the researchers in boat propeller guard cases. The studies and experts were extremely successful in court. They were also successful in scaring off potential litigants before they even filed legal cases.

    In the early 1990’s Mercury and OMC also began perfecting their “get out of jail free card” to put an end to all these propeller cases. They claimed the U.S. Coast Guard’s failure to require all boats to have propeller guards in the 1971 Boating Safety Act established a Federal Preemption. This Federal Preemption prevented requiring propeller guards on any specific boat.

    As Mercury and OMC continued to win cases based on Federal Preemption, and the precedent was set. The importance of the three propeller guard studies began to wane. Mercury and OMC basically began to just show up in court, claim Federal Preemption, win the case, and go home.

    Federal Preemption was their “get out of jail free card” until the U.S. Supreme Court struck down the Federal Preemption defense in the Sprietsma vs. Mercury Marine case in December 2002.

    Since then, the original three studies (the NBSAC study, the SUNY head impact study, and the SUNY leg impact study) have been regaining importance. The 1989 NBSAC report is once again the keystone of the industry’s defense. It is frequently backed up with litigation testing (industry testing of proposed alternatives in a manner to make sure they fail).

    The three propeller guard reports are also touted when propeller safety regulations have are proposed by the Coast Guard. This can be seen in the 1995 Federal Register where they are used against a 1995 houseboat and displacement boats propeller safety proposal.