PropellerSafety.com

Archive for outboard

The Leash, a tether for large outboard motors, entered the market in early 2016. They especially focus on preventing bass boat outboard motors from entering the boat after striking a floating, submerged, or fixed object.

Their patent application was filed 22 December 2015 and published 18 months later on 22 June 2017 by the U.S. Patent Office as Publication Number US2017/0174303 A1.

Roy John Grohler of Kentucky is the inventor. The patent is assigned to The Leash Tether LLC. of Kentucky.

The Leash: left and right views side by side

The Leash: left and right views side by side

. Read More→

In December 2013 we published a report, Approaches to Prevent Outboard Motors From Flipping Into Boats After Striking Floating or Submerged Objects in which we identified several ways to prevent outboard motors from breaking off and flipping into boats after striking submerged objects. One of those was was active trim control (see pages 33-34 of our report) by using a magnetic fluid in the trim (tilt) cylinder and using position feedback (how far is the rod extended) during a log strike to adjust how much resistance the cylinder is applying to the upward swinging of the outboard. While the impacts are not as severe, the same approach is used for shocks on several cars.

Magnetic fluids are sometimes called Magneto-Rheological (MR) fluids. Also sometimes spelled as magnetorheological fluids. They change viscosity based on the presence of a magnetic field and upon its intensity.

Active control brings the ability to respond faster than existing systems and limit pressure overshoot today’s relief valves. It also provides the opportunity to measure the magnitude of the collision as it is occurring and then select the best way to respond or possibly to select one of several preprogramed ways to respond. One program could allow the outboard to rise up over the object before maximum resistance is applied (called trailover).

MR fluids are also currently used in some high end, rough water vessel chairs to dampen vibrations (protect your back in very rough water) for the U.S. Navy.

In January 2015, Brunswick filed a patent on this active trim cylinder approach that includes some interesting comments.

Brunswick’s patent, U.S. Patent 9,290,252 was issued 22 March 2016.

Delph Magneride image we posted with our discussion of using MagnetoRheolopical fluids in trim systems in 2013.

Delph Magneride image PropellerSafety.com posted with our discussion of using MagnetoRheolopical fluids in trim systems in 2013.

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Outboard can strike submerged object, break off, and flip into the boat warning

Outboard can strike submerged object, break off, and flip into the boat warning

In 1970, William Haddon, Jr. a well known safety expert published a ground breaking safety article:
 
On The Escape of Tigers: an Ecological Note.
by William Haddon, Jr.
American Journal of Public Health.
December 1970. Vol.60. No.12. Pages 2229-2234.

The the article has since been widely republished and reprinted.

The thesis of the article is that per Mr. Haddon, by 1970 The United States and most developed nations had made significant progress against “living environmental hazards” (medical issues caused by living organisms such as germs, bacteria, etc.). However, similar progress had not been made against “non-living hazards” (accidents leading to injury or death).

The field of Medicine had many strategies and processes by which to attack emerging problems causes by living organisms (such as the Zika virus in current times). While science may not immediately defeat the Zika virus, the basic processes and methods to use to begin to develop a means to combat such a threat are well known.

That same basic structure of processes by which to develop a means to combat an emerging health risk caused by a living organism did not exist to combat a health risk caused by a non-living structure (such as some new type of accident that injures or kills humans).

In his paper, Haddon tried to bring structure to the process of mitigating or eliminating accidents resulting from the sudden release of energy.

In order to better marshal resources against these “non-living hazards”, William Haddon, Jr. suggested that many of them result from “the transfer of energy in such ways and amounts,and at such rapid rates, that inanimate or animate structures are damaged. (Like a bass boat outboard motor striking a submerged object, breaking off, flipping into the boat, and striking those on board with its still rotating propeller). Haddon goes on identify some harmful “non-living hazards” that interact with people and property as: hurricanes, earthquakes, projectiles (like an outboard motor), moving vehicles (like a boat), ionizing radiation, lightning, conflagrations, and notes the cuts and bruises of daily life illustrate our interaction with the rapid transfer of energy.

The paper’s title derives from one example of the quick release energy, the release of tigers. Read More→

Evinrude operators manual warning for outboard may break off and enter boat after striking submerged objects.

Evinrude operators manual warning for outboard may break off and enter boat after striking submerged objects.

Bombardier and Mercury Marine outboard operators manuals have long warned parts of or all of an outboard motor may enter the boat after striking a submerged object.

An example from the 2012 250 horsepower Evinrude E-tec manual is shown at right.

A big thanks to Bombardier Recreational Products & Vehicles (BRP) for putting their operators manuals online.

Some manufacturers sell the manuals at price point preventing many from ordering them. Bombardier does sell the manuals if you want a paper copy, but they also make them available online. Those who may have lost the manual or purchased a used boat without the manual, have free access to the outboard manuals.

We encourage all boat and marine drive manufacturers to make their operators manuals available online in the interest of boating safety. Read More→

We charted the the Design Flow Process designing outboard motors in a manner that prevents them from entering the boat after striking submerged objects. The chart was designed specifically with tournament bass boat outboard motors in mind.

The chart has since been updated since it was originally posted. The most recent version is below.

Flip In Design Chart

Flip In Design Chart

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Most major outboard manufacturers conduct a log strike test on new outboard models to prove durability.

Manufacturers either test them on the water by actually running over a log of a given type, diameter, and length, or on a test stand they think simulates on water testing.

These impact tests are typically conducted at a speed based on the horsepower of the outboard. Testing tends to start at a lower speed, then build up to the maximum speed selected for the test. Some manufacturers conduct more that one test at the maximum speed tested.

In general, the outboard must still be operational (run) after the test, the cowl is to remain attached, and the outboard is to be capable of at least limping back to shore (capable of some steering and of some trim). The outboard is to have no major oil leaks. At least one manufacturer say no parts of the outboard are to enter the vessel during the testing.

Focusing our discussion on larger outboards, especially those targeting tournament bass boat applications, most manufacturers impact test them at maximum speeds of the nature of 30 to 40 mph.

The problem is tournament bass boats tend to run 70 mph or faster. Read More→

Numerous previous posts concerned outboard motors striking submerged objects, breaking off, and flipping into boats, preventing or mitigating those accidents, log strike systems, accidents and legal trials involving such accidents and related topics.

We will now be covering this topic in this category of the PropellerSafety blog.

If anyone wonders why we are covering these accidents on PropellerSafety.com, its because outboards that break off and enter the boat typically come in with the engine still running, the propeller at a high RPM, and often result in severe or fatal propeller injuries. Read More→

We updated our Outboard Motor Struck Submerged Object and Flipped Into Boat list today (2 May 2016).

We still have many more to add to the list above plus the 2015 U.S. Coast Guard Boating Accident Report Database (BARD) will be out with more soon as well.

We also updated our list of Bass Boat Outboard Motor Struck Submerged Object & Flipped into Boat list today (2 May 2016).

Several of these accidents resulted in propeller injuries or fatalities.

We encourage those working on preventing these accidents to view our paper titled, Approaches to Prevent Outboard Motors From Flipping Into Boats After Striking Floating or Submerged Objects. We also have considerable additional information that had not yet been integrated into that report.


Back in February 2012 we developed a list of outboard motors striking submerged objects, breaking off, and flipping into boats. We instantly noted a large percentage of these accidents involve bass boats with high horsepower outboard motors.

We have since identified 21 occurring since February 2012, plus several earlier ones. Many of the accidents we continue to identify are bass boats in which either the outboard motor swivel bracket broke, or the jack plate failed to retain the drive and the outboard jumped into / entered the boat.

Three of these accidents involving bass boats occurred within a 30 day period spanning April and May 2014

To better call attention to this issue we created a list of outboard motors of 150 or more horsepower that have flipped /jumped into boats since 1999. Much more information on each of these accidents is available from the full list of accidents linked to above.

As we mentioned on the list of outboard of all sizes jumping in, this is only a partial list of accidents. Many accidents are not reported and many states refuse to make their accident reports public in the U.S. Coast Guard Boating Accident Report Database (BARD).

Several of these bass boat accidents occurred during tournaments or pre-fishing for tournaments, and some involve well known bass fishing professionals (bass pros). Read More→

Rex Chambers' boat with outboard motor broke off

Rex Chambers’ boat with outboard motor broke off

We updated list of boat accidents on our Outboard Motor Struck Submerged Object and Flipped Into Boat page today (2 June 2014).

The updates included one 2002 accident, several 2013 accidents from the recently released USCG 2013 Public Boating Accident Report Database (BARD),
and the recent Todd Iwamoto and Rex Chambers accidents.

We also added BARD reference numbers to the 2013 accidents we had previously identified.

Once again, we would like to call the boating industry’s attention to the number bass boats with large outboards are appearing on this list in recent years, several of which were participating in bass tournaments. We previously published a 74 page pdf document containing an extensive list of ways to mitigate and prevent these accidents on various types of vessels, including bass boats:

Approaches to Prevent Outboard Motors From Flipping Into Boats After Striking Submerged Objects.

We encourage the boating industry to apply those or other methods where appropriate, and especially call their attention to the bass boat issue.