PropellerSafety.com

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 →

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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 →

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Dennehey: Another Catamaran propeller accident

Shane Dennehy was on a college spring break trip organized by StudentCity in the Dominican Republic on March 2019 at Punta Canna.

Student City organized a “booze cruise” on a catamaran named “Escandaloso”

Shane Dennehy is now (November 2019) a junior at State University of New York in Binghamton, New York.

Shane and his parents have sued StudentCity for $25 million dollars following his 20 March 2019 propeller accident.

They allege the Escanaloso was not on the list of previously vetted and approved vessels and no StudentCity employees were onboard.

When the boat was close to shore Shane went down a slide from the second deck. He entered the water between the two engines. He grabbed the edge of one of the motors to steady himself moments before the captain started the engines.

He became entrapped on the propeller. They had to remove the boat propeller to free him.

Catamaran with slide

Note we have NO reason to believe this is the particular boat
it just an example of similar vessels in the area

In the image above and in similar images of other Punta Canna party catamarans, the pile of red things at the back of the vessels is life jackets.

The lawsuit alleges students and bystanders tended to him and got him to shore on a private boat, then carried him to a taxi which took him to a hospital.

The suit alleges many shortcomings in the level of care provided by StudentCity including negligence in several acts.

We have seen this played out several times before in propeller accidents in third world water tourism areas.

We have no specific knowledge of this specific accident beyond what we read in the press. However, we have seen similar claims from many families in the past including several involving catamarans. Several sail cat accidents are listed in our post titled, Casey Schulman Was Not the First: Catamaran Dive, Snorkel, & Party Boat Propeller Accidents.

From some online searching we suspect the catamaran in this accident was a powerboat. Several powered catamarans with upper deck slides operate party boats / booze cruises in Punta Canna.

Many more are listed on our page titled, Tourists Being Struck and Killed by Boat Propellers in Diving / Snorkeling Areas.

Most of the coverage of the Dennehy accident in the post above was gleaned from a 4 November 2019 story by Salem News titled, Peabody travel firm hit with $25M suit over spring break injury. We thank Salem News for their coverage of this accident.


What a Difference a Year Makes

StudentCity’s website currently announces they will no longer be providing spring break tours for 2020.

StudentCity website November 2019 after the March 2019 propeller accident

StudentCity website as of November 2019

While back in 2018 things were much racier. We limited the post below to tamer portions of their home page.

StudentCity website in 2018

StudentCity website in 2018


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Sharrow Propeller receives rave review from BoatTest

Sharrow Propeller is one of many propeller developments we have followed over the years. The loudest ones sometimes turn out to be all hype focused on luring investors into an unproven technology with some big names associated with it. A few have staying power. It sounds like Sharrow Propeller may be the latter.

Sharrow Propeller image courtesy BoatTest

Sharrow Propeller

BoatTest.com a trusted industry source for boat performance test data, published a reviewed the Sharrow propeller in BoatTest’s 14 October 2019 newsletter. As far as technology and performance goes the Sharrow propeller received a rave review.

BoatTest.com Review of Sharrow Propeller

BoatTest spent 7 days testing this propeller.

The specific Sharrow propeller tested was called the Sharrow Propeller MX-1 that had been 5-axis router cut from a relatively soft billet of aluminum alloy per BoatTest.

BoatTest tested the Sharrow propeller on a 3500 pound bowrider vs a 14-3/4 inch diameter 15 inch pitch three blade stainless steel propeller they say is an industry favorite. They also tested it against a premium 15 inch diameter 15 inch pitch three blade stainless steel propeller that could plane at lower RPM than the first propeller.

Test crews noted reduced vibration with the Sharrow and easier handling. They noted the boat seems more tightly connected to the water because it basically has six blades grabbing the water.

The Sharrow generally went faster than the other props, reduced slip, improved gas mileage, got on plane faster and at a lower RPM, and had a faster top speed. The test crew was used to some propellers performing better at slower speeds or at higher speeds, but labeled the Sharrows better performance on both ends as “a remarkable result.” The Sharrow also reduced noise and vibrations while improving handling in reverse. BoatTests’ list of 12 positive conclusions is indeed remarkable.

BoatTest noted that Sharrow was actually disadvantaged in the test by them using an aluminum propeller vs the stainless steel propellers they competed against.

BoatTest posted a 14-1/2 minute video of their review on YouTube

Sharrow says they intend to officially debut the propeller at the 2020 Miami Boat Show.

BoatTest went to great lengths to explain how fair and accurately they tried to record data during this review and the considerable efforts they took in doing so. The Sharrow’s results almost sound like a test report dated April Fools Day. But, banking on the proven history of BoatTest we suspect the results are true.

Sharrow is currently using 5-axis cutters to mill away everything that does not look like the propeller out of a large block of aluminum to make prototypes and suggests that may eventually be the mode of manufacture.

Sharrow Propeller production image courtesy BoatTest

BoatTests article shows them using casting patterns cut from 3D printed wax, but their 3D printing capabilities are not at the stage to scale to production volumes.

PropellerSafety comments

We are thrilled to see a new propeller design finally receive rave reviews from a trusted testing source.

We are excited, wish Sharrow Propeller the best, and congratulate them on the performance they have achieved.

While that is wonderful and exciting, we can pretty much guarantee it will not all be clear sailing ahead.

Major obstacles in addition to funding include determining how to manufacture the propeller as economically as possible while maintaining the quality needed. As per the image above, some are currently made by hogging them out of large blocks of aluminum, a very costly method.

In our previous writings about the recreational boat propeller market we have noted the challenges of developing tooling required for manufacturing a wide range of diameter and pitch propellers that are individually targeted for certain types of applications (different rakes, cupped, etc) with 3 or 4 blades. Plus do not forget the need to make them available in both aluminum and stainless steel. Most propeller manufacturers now use a hub with inserts that can be adjusted to the many combinations needed to attach to drives from different manufacturers, sizes, and model years.

Sharrow’s ribbon shaped blades almost look like mobius strips. Pouring aluminum or stainless steel in these shapes and totally avoiding voids and imperfections could be challenging.

Sharrow’s design makes one wonder if one of Mercury Marine’s various lost foam casting methods might work?

Another question is propeller repair. Aluminum propellers are known for their ability to be repaired relatively economically with tooling already in the hands of countless prop shops. Stainless steel props are thinner and tend to be more challenging to properly repair after a substantial impact with a log, rock, concrete boat ramp, etc.

Where will the Shallow fall on that continuum? The ribbon blades look like they might be easily damaged and hard to repair. Meaning propeller life may not be as long as normal aluminum propellers.

Does the Sharrow wind up loose ropes and lines like a normal propeller?

We note Sharrow has their eye on much larger vessels on up to Super Tankers as possible customers benefiting from reduced fuel consumption. If they could be wildly successful on larger vessels their cash flow could fund more investment in recreational vessel propeller development and manufacturing.

Wonder what Sharrow’s goals are? Did they enter this market hoping to be acquired? Do they really plan to develop a facility and all the technologies required to manufacture these propellers in production quantities for all sizes of vessels? Or do they plan on licensing the technology to players in the different propeller markets (recreational vessels, yachts, passenger vessels, larger vessels, huge vessels, military vessels, etc)?

How About Propeller Accidents

The Sharrow Propeller looks vastly different than typical propellers. We have no idea how it performs in terms of possibly showing people out of the area between the blades like the Australian Safety Propeller did OR what its entrapment performance might be, Is it more likely, less likely, or the same to entrap human limbs and appendages, clothing, and/or ropes than a normal propeller?

Is the stronger grip of Sharrow propeller on the water more likely to pull people behind the vessel into the propeller? More likely to pull in those who fell from skis, boards or inflatables when you go back around to pick them up?

Seems like it is time to start running over stuff. Propeller guard manufacturers have long been known for running over all kinds of stuff to test their guards: large squash, cabbage, water melons, dead goats, blown up dolls, wild boars, barrels with hide on them, and many other items. It would be interesting to see the Sharrow propeller runover some of these objects to see how both it and the object look after impact.

It might also be interesting to run the U.S. Coast Guard propeller guard test protocol with an open Sharrow Propeller in comparison to a traditional propeller.

Again we have no concept whether the Sharrow is better, worse, or the same in comparison to normal propellers from a propeller safety standpoint. We just suggest that its performance should be evaluated before it was widely accepted on recreational boats, especially on recreational boat applications known to be more frequently involved in propeller accidents.

Congratulations and Thanks

A big thanks to BoatTest.com for running this test and taking such care to make sure the evaluation was honest, fair, and accurate.

Plus Congratulations again to Sharrow Propeller for having such a tremendous design. We wish them the best in the marketplace.


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The Leash awarded 2nd U.S. Patent

The Leash was awarded U.S. Patent 10,435,128 “Outboard Motor Tether” on October 8, 2019. This new patent enhances their patent portfolio increasing their level of patent protection beyond their earlier patent, U.S. Patent 9,771,136.

The Leash, a tether to prevent outboard motors from breaking off and flipping into boats, continues to be a popular accessory on bass boats and especially on tournament bass boats.

The Leash on Chris Lane's boat during 2016 Bassmaster Classic photo is an edited version of Bassmaster's Bling Gallery image #24

The Leash on Chris Lane’s boat during 2016 Bassmaster Classic
photo is an edited version of Bassmaster’s Bling Gallery image #24

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Kevin Rivera-Cornejo killed by rental houseboat propeller on Shasta Lake

Kevin Rivera-Cornejo, 23 of San Jose California, was on the swim deck of a rental houseboat at Corey Cove on Shasta Lake in California about 4:30pm Friday 6 September 2019.

His father, Hector Rivera, was at the controls beaching / mooring the houseboat. Onboard were family and friends.

Kevin either jumped in or fell into the water when the houseboat was being reversed.

houseboat marina on Shasta Lake in 2006

a houseboat marina on Shasta Lake back in 2006

Initial reports say Kevin screamed and his father stopped the boat. Kevin Rivera-Cornejo “sustained fatal propeller cuts to his lower extremities” per KRCR News. Read More →

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USCG releases Recreational Boating Statistics 2018

USCG Recreational Boating Statistics 2018

USCG Recreational Boating Statistics 2018

U.S. Coast Guard released their annual 2018 recreational boating accident statistics report on 26 August 2019.

Total counts for 2018 Coast Guard Boating Accident Report Database (BARD) reported accidents, injuries, and fatalities were down compared to 2017.

2018 USCG BARD reported accident statistics were 4145 accidents, 2,511 injuries, and 633 fatalities.

2017 USCG stats were 4,291 accidents, 2629 injuries, and 658 fatalities.

For 2018 USCG reported 177 propeller accidents, 177 injuries, and 25 fatalities.

2017 USCG stats were 172 propeller accidents, 162 propeller injuries, and 31 fatalities.

Thanks to all those at USCG whose efforts helped make this annual statistical report of boating accidents possible.

We would also like to thank USCG, law enforcement officials, lake patrols, first responders, nurses and physicians, those offering boating safety classes, boat safety equipment check points, safe boaters, state boating law administrators, life jacket loaner program participants, Operation Dry Water, those spreading boating safety messages, and all others who work tirelessly to drive these annual totals down.

Plus thanks to all the state boating law administrators and all the officers in the field filling out the accident reports, and to the individuals that self reported their accidents.


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Media still misleads boaters on Kali’s Law impact on fatalities

Our June 2019 post, Kali’s Law: Misleading Fatality Statistics explained in detail how the media is publishing misleading boating fatality statistics surrounding Kali’s Law.

Kali’s law will require the use of kill switch lanyards on certain power boats under 26 feet beginning September 1st, 2019 in the State of Texas.

Texas media outlets continue to vastly over estimate the number of boating fatalities per year that will be prevented by this law.

For example, today, 22 September 2019, CBS Austin posted a story titled, “‘Kali’s Law’ goes into effect Sep. 1st, aims to cut down on deaths from boating accidents”. Portions of that article are copied below.

Kali's Law CBS Austin report

Kali’s Law CBS Austin report 22 August 2019

As seen in the article, CBS Austin says if Kali’s Law had been in effect in Texas in 2018, instead of 29 fatal boating accidents, they would have only had 3.

That is a gross misstatement of facts. Read More →

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RYA Kill Switch lanyard wear PSA 2019

Royal Yachting Association (RYA) of the United Kingdom (UK) released a great “wear your kill switch lanyard / kill cord” Public Service Announcement (PSA) August 6, 2019.

In the UK kill switch lanyards are referred to as “kill cords”.

RYA’s PSA is titled A Kill Cord Could Save Your Life.

While the PSA is supported by an online page of text, it will be best known for the accompanying 1 minute video below.

RYA Kill Switch Video

RYA Kill Switch Video

Read More →

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Sensor Based Detection of people near boat propellers: Patents

The phrase Virtual Propeller Guard broadly refers to methods used to detect the presence or likely presence of people or objects in the water that may be struck by or pulled into a boat propeller. Long ago we posted a more concise definition of Virtual Propeller Guards.

With increasing activity in the use of sensors to detect people at risk of being struck by a boat propeller we decided to try to bring most of the relevant patents on the topic together in one location.

In the instance of this post, we will only be referring to patented approaches using sensors to detect the presence of people in the water at the stern / behind the transom of a recreational boat. Those in the water may include swimmers, floaters, those on tubes, those on or at the swim ladder, water skiers, wake boarders, wake surfers, those standing in shallow water near the vessel, those riding a PWC, those in a Kayak or Stand Up Paddleboard (SUP), people being rescued, or any other conveyance or activity that may place people in the water behind the stern of a recreational power boat within a distance of about 10 feet of the boat propeller. Patents listed below may not cover the entire range of applications or distance described above.

The Volvo Penta image below is an example of these types of patents.

Volvo Penta Patent 8,195,381

Volvo Penta U.S. Patent 8,195,381 sketch

Read More →

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Brunswick Neural Network Person Detection patent issued

We continue to salute Brunswick for their efforts to detect people in the water near a recreational boat.

Basics of the Patent

U.S. Patent 10,372,976 Person Detection in a Marine Environment invented by Troy Kollmann and Jon Nowick, assigned to Brunswick issued on 6 August 2019.

The patent’s first claim describes detecting people in the water near vessels (1) using at least one image sensor, (2) that “at least one image sensor” detects visible light, (3) that “at least one image sensor” is at at angle and distance to the water at the rear of the vessel, (4) the images are scanned to detect the presence or absence of a person, (5) the scanning module includes an Artificial Neural Network (ANN), (6) that ANN being trained to detect patterns within the image associated with a person in the water behind the vessel, (7) the system outputs detective information regarding the presence or absence of a person in the image, (7) wherein the ANN module is trained using positive and negative images of objects in the water from a similar viewpoint and distance at the stern.

U.S. Patent 10,372,976 Person Detection in a Marine Environment

Read More →

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2019 USCG Reauthorization bill: mandatory kill switch wear?

The U.S. Coast Guard is reauthorized each year in an annual bill in which some changes may be introduced.

Attwood Marine Products universal (7 key) boat lanyard / kill cord

Attwood Marine Products universal (7 key) boat lanyard / kill cord

The 2018 USCG reauthorization bill as passed requires engine cut off switches (kill switches to prevent the Circle of Death) be installed in most recreational power boats less than 26 feet in length.

The 2019 USCG reauthorization bill as it has passed the House (HR 3409) required mandatory kill switch wear on recreational power boats less than 26 feet in length when underway if a kill switch is present.

Per the National Marine Manufacturer’s Association (NMMA) the bill would also “grant the Coast Guard “equivalency” authority, allowing the Coast Guard to streamline approval of the recreational boating industry construction standards and new technologies, while maintaining the highest level of safety.”

Currently, and historically USCG requirements pertaining to boat building and boating safety that are codified into Federal Regulations are sometimes dated (old and no longer represent current practices), plus they may not specially allow the use of more modern technologies that have since become available. It takes considerable effort and time to change Federal Regulations. Plus in the current environment it has become even more challenging. It sounds like this part of the legislation may help with these problems.

This bill will still have to pass through the Senate, likely require being resolved between the two houses, and be signed by the President of the United States. Read More →

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