PropellerSafety.com

LifeCord – smart kill switch lanyard

Inspired by the 2013 Milligan accident in the UK, John Barker, a UK businessman did something about the problem.

LifeCord logo
At least in the UK, some boaters, especially those in rougher water want to attach their kill switch lanyard (known as a kill cord in the UK). However sometimes they forget to attach the lanyard. This new invention calls attention to itself if it is not connected.

Before you start the boat you must attach the kill cord to the boat. LifeCord uses your existing kill switch. It comes with a variety of connectors so it fits all popular engines.

Once attached it begins to flash a light every ten seconds and beep at that same rate. The beeping starts at a low decibel rate and gradually gets louder every 10 seconds until you attach the lanyard by wrapping it around your leg or by attaching it to your life jacket. A different end piece is used for your leg that the special snap used for your life jacket.

LifeCord is basically a “smart” kill switch lanyard that reminds you to attach it so you do not end up in the “Circle of Death” with an unmanned boat circling, repeatedly striking you with the propeller.

If you elect to try to defeat the system by just latching it back to itself in either mode, LifeCord knows you are cheating and will continue to flash and sound the ever louder alarm.

By starting out at a light beeping sound, it gives you plenty of time start the engine and check a few things on the vessel and pull the bumpers between you and the dock before the beeping gets loud.

LifeCord accomplishes this feat with the parts below.

LifeCord assembly

LifeCord assembly
MBY image

Read More →

3 Children tubing struck by boat propeller Norris Lake TN 8 June 2018

Four children were riding a towed tube on Norris Lake north of Knoxville Tennessee on Friday, June 8, 2018.

The boat was near Goat Rock Island in LaFollette, Tennessee at White Bridge in Lonas Young Memorial Park per 10news / WBIR.

The boat was a small center console boat powered by a Johnson outboard motor, as seen below.

WBIR image of the vessel

WBIR image of the vessel
8 July 2018 Norris Lake TN

The children were still on the tube when the boat headed at them, a 16 year old girl and another child jumped from the tube, a six year old and an 8 year old staid on the tube.

The 16 year old girl that jumped, plus the 6, and 8 year old were struck by the propeller. Read More →

Mercury patented outboard motor tether in 1969

The Leash, labeled image.

The Leash, labeled image.

With all the chatter about The Leash we thought we would point out the first commercially available outboard tether for larger outboards was invented and sold by Mercury Marine.

Mercury’s efforts preceded The Leash by nearly 50 years.

This post is best viewed on a laptop or desktop computer.

This post in no way belittles the development of or the accomplishments of The Leash, it just points out the basics of the concept have been around a long time. It also points out that one outboard manufacturer not only condoned the use of tethers, they factory installed them on tens of thousands of motors.

Back on January 12, 1967, Brunswick Corporation filed two patent applications that were later issued as the patents listed below:

  • U.S. Patent 3,434,448 Combined Impact Damping and Power Lift Mechanism for an Outboard Propulsion Unit Assembly invented by W.L. Woodfill issued 25 March 1969, assigned to Brunswick Corporation (parent company of Mercury Marine).
  • U.S. Patent 3,434,450 Mounting Arrangement for Hydraulic Impact Damping and Power Lift Means for an Outboard Propulsion Unit invented by well known Mercury engineer, D.F. (Dan) McCormick issued 25 March 1969, assigned to Brunswick Corporation (parent company of Mercury Marine).

The first patent teaches how to combine the damping needed to stop an outboard motor swinging up after striking a submerged object, with the power lift system as seen on the “Tower of Power”, the tall large horsepower Mercury outboards.

The second patent focuses more on the mounting arrangement used to accomplish the first patent.

We do find it a bit odd these two relatively complex patents list two separate inventors vs. listing them as co-inventors on each patent. They even share the same drawings. The first patent focuses more on the tether and specifically includes it as a claim in the patent.

Mercury’s tether is a heavy nylon strap about 1.75 inches wide and about one to two feet long (they come in different lengths depending on the outboard model and model year).

The tethers have a loop on both ends allowing them to be slipped over a metal rod.

In operation on the tower of power outboards, one looped end of the tether slips onto a rod on the swivel bracket (note a tube allowing the tether to swivel more easily is slipped over the rod first, then the looped end of the tether is slipped over the tube). The strap then loops around a metal bar on the outboard mounting bracket structure that is firmly attached to the transom, then the remaining looped end slides over the same rod on the swivel bracket that the first loop slipped on. See photos near the bottom of this post for how Mercury’s tether is assembled. The swivel bracket is tethered to the transom, just like The Leash.

The tilt cylinder(s) use external relief valves and check valves to allow the cylinder rod to collapse during collision with a submerged object which allows the swivel bracket to swing up with the rest of the outboard. Read More →

Mercury Marine Aluminum Alloy patents & propeller safety

Rex Chambers' Mercury Marine outboard broken swivel bracket

Rex Chambers’ Mercury Marine outboard broken swivel plate

As noted before, outboard motor swivel brackets take tremendous loads during a collisions with submerged objects. On occasion swivel brackets fail, sometimes allowing the outboard motor to break off and flip into the boat with the engine still running and the propeller turning a few thousand RPM.

Driveshaft housings (the lower leg of the outboard) sometimes fail during log strikes.

Several years ago, Mercury Marine developed two new aluminum alloys with higher impact resistance for use in their lost foam molding process.

The very basics of what happened is Mercury found that small quantities of Strontium could make certain aluminum alloys more durable, allowing parts made from them to stretch more before incurring a permanent set which allowed their structural parts (like swivel brackets) to absorb more energy during a collision with a submerged object before failing. These alloys were not just more durable, they were more durable at high strain rates (when a load was applied very quickly such as during a crash). Thus Mercury was able to raise the speed at which their components would fail in some collisions.

In addition to increasing durability of Mercury’s parts, the specific blends of elements used by Mercury in their new alloys brought along some other good features as well, like fewer issues with porosity.

These two new Mercury alloys went on to be known as:

  • A367 or Mercalloy 367 used for structural parts
  • A367 or Mercalloy 368 used for propellers

Most major manufacturers of marine drives run one or more special blends of aluminum to achieve the qualities they desire specifically including reducing corrosion and being compatible with their molding process (die casting, lost foam, low pressure lost foam, etc.) For example, Yamaha uses an alloy they refer to as YDC-30.

The history of Mercury patenting their two new alloys is told below.

In 2005, Mercury Marine filed two patent applications for these new alloys: Read More →

Rex Chambers speaks on The Leash: video

Rex Chambers, well known professional bass angler and his fishing partner were injured 3 May 2014 on Wheeler Lake in Alabama when they struck a submerged log, the 250 horsepower Mercury outboard motor broke off, and flipped into the boat still under power. His fishing buddy was struck in the head by the skeg. Rex was cut in the left shoulder and left leg by the propeller. See our previous coverage of Rex’s accident.

On 3 May 2018, the four year anniversary of his accident, Rex posted a video on his Facebook page, Rex Chambers Fishing, reminiscing from Lake Wheeler about the accident and telling about how he now runs The Leash, a tether to prevent such accidents.

We like his down home, straight forward talk and how he is able to speak from personal experience of the need to tether large outboard motors.


Stages of grief: boating industry resists proposed safety devices

Navigator Prop Guard Down Position

Navigator Prop Guard Down Position

The recreational boating industry has long used a series of objections in their efforts to resist proposed safety devices, including propeller safety devices. The industry raises different objections during different stages of the process. Overall the process resembles the 5 stages of grief people pass though when a loved one dies.

The five stages of grief:

  1. Denial
  2. Anger
  3. Bargaining
  4. Depression
  5. Acceptance

We have long seen this sequence of objections used against propeller guards. Some of these steps were used against kill switches long ago, and now some are being used against The Leash, a device to prevent outboard motors from breaking off and flipping into boats after striking submerged objects. PWC off throttle steering devices passed through these steps too, along with automatically limiting maximum PWC speeds.

These steps are basically the playbook the industry pulls out every time a new safety device is proposed.

Steps within the five stages are listed below, along with some examples. Read More →

Randy Howell runs The Leash: video

Randy Howell and The Leash recently posted a video of Randy explaining why he runs The Leash, a tether to prevent large outboard motors from breaking off and flipping into boats after striking submerged objects or when running in rough water.

Several outboard motors have flipped into boats while the outboard motor is still under power with the propeller rotating at thousands of RPM striking those on board.

Randy is a well known figure on the pro bass angler circuit associated with several sponsors including outboard motor manufacturer Mercury Marine.

Randy Howell runs The Leash


Propeller Guards: ABYC Marine Law Symposium

ABYC logo

ABYC logo

ABYC’s Marine Law Symposium 2018 was originally scheduled to be part of ABYC’s annual Standards Week in Charleston, South Carolina in January 2018. However, a major east coast snowstorm postponed the event until 10 April 2018.

The theme of the topics selected was, “The Anatomy of an Accident”.

The day long event featured sessions titled:

  • Legal 101 (legal terms and phrases)
  • Are You Covered (marine insurance with a focus on types of insurance that might be needed by a marine surveyor)
  • First Responders (boat accidents from the point of view of a marine law enforcement professional, and what information might be available)
  • Case Study #1 a warranty claims case
  • Case Study #2 standards and record keeping issues surrounding an outboard motor falling off underway
  • Case Study #3 legal and engineering principles used to limit sailboat builder’s exposure when an older sailboat capsized
  • Case Study #4 The Case for Propeller Guards
  • Case Study #5 case in which paths prior to a collision were established

Attendees: there were about 80 people in attendance, predominately male marine surveyors. The remainder included well known expert witnesses, legal firms mostly those associated with defending the industry, representatives of two state fish and wildlife departments, some boat builders, a few individuals from the insurance industry, a marine drive manufacturer, a component manufacturer, a manufacturer of composites, and at least one houseboat rental operation.

Among the better known names in the propeller accident field present were, Robert Taylor of DRE, Ed Fritsch and Robert Swint of ATA, William Daley of CED, and Jim Getz of Boat Accident Reconstruction Experts. Robert Taylor and William Daley were both on the program. I met Mr. Taylor and we chatted from time to time during the day. He wowed us with his interlocking fingers representation of how threads interlock for matching bolts and nuts vs. mismatched bolts and nuts during one presentation. Robert Taylor remains very smooth in explaining complex matters in legal settings and it is no wonder he was popular here.

John Adey of ABYC welcomed us to the meeting and recognized people with differing viewpoints to the industry were present. He invited everybody to join ABYC. Mr. Adey said that over time he has become more comfortable and accepting of those with opposing viewpoints to the industry as he frequently interacts with us on all kinds of matters.

Our post focuses on Case Study #4: The Case for Propeller Guards. Read More →

Barhanovich case update 6 April 2018

The Barhanovich case resulted from a boat accident off Biloxi Mississippi in which a large Suzuki outboard motor allegedly struck dredge pipe, broke off, flipped into the boat and killed Mark Barhanovich on Sunday morning 16 September 2012.

Mark Barhanovich's center console fishing boat. Photo from Edward Fritsch expert witness report

Mark Barhanovich’s center console fishing boat.
Photo from Edward Fritsch expert witness report

In our last update we updated the status of the Barhanovich case as of 5 November 2016. Previously, the dredge firm, Bean, settled with the Barhanovich family and began trying to recover some of those funds from Suzuki of Japan. An argument ensued concerning the admissibility of an initial and an updated expert report by Bean’s expert, Edward Fritsch of ATA. Suzuki was able to obtain a summary judgment in Federal District Court throwing out both reports, and with it much of Bean’s case. Bean appealed to U.S. Court of Appeals for the Fifth Circuit, and was allowed to proceed using Mr. Fritsch’s 2nd report. We covered that decision in our 5 November 2016 post.

Since then, the U.S. Coast Guard finally allowed full access to the vessel. A procedure was agreed upon to take material samples from the swivel bracket and analyze them for material content, strength, hardness, etc. The actual testing was done by an outside firm.

Samples were obtained. Both sides secured experts to analyze and report the data.

Suzuki moves to reject Mr. Bartlett’s 2nd report

Suzuki of Japan claims Bean’s expert (Robert D. Bartlett of Bartlett Engineering) enlarged his claims and inserted new causes of failure in his 2nd report (analysis of the data), while he was supposed to only use the data to address issues he had previously raised (per Suzuki). Read More →

MagBlade Safety Propeller awarded U.S. Patent

MagBlade Propeller

MagBlade Propeller

The MagBlade safety propeller that came on the scene a half a dozen years ago in South Africa, has been acquired by MagBlade Limited based in Hong Kong.

U.S. Patent 9,909,600 was issued to Russel Iwan Hawkins, one of the individuals in South Africa we spoke to a few years ago, on 6 March 2018 by the U.S. Patent Office.

The design involves blade edge covering members that are releasably securable to at least part of the edges of the propeller.

We first covered the propeller in an August 2012 post.

The propeller design is said to have been improved since then and their website has a “Get in Touch” link through which you can contact them for further information. Read More →