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Archive for March 2012

Effectiveness of Propeller Guards

CED Propeller Guard Testing @ SUNY

CED Propeller Guard Testing @ SUNY

About 2006 the U.S. Coast Guard began consulting and contracting with some experts to produce a test protocol for propeller guards. The American Boat and Yachting Council (ABYC) and CED Investigative Technologies are now finalizing that process for USCG. CED Investigative Technologies is a forensic engineering and accident reconstruction firm specializing in providing legal support to legal firms, insurers, and manufacturers.

ABYC and CED have completed the rough draft of their propeller guard protocol, titled “The Effectiveness of Propeller Guards” and are now putting it out for public comment before delivering the final draft the the U.S. Coast Guard later this Spring. Read More→

Dr. Lawrence E. "Larry" Thibault

Dr. Lawrence E. "Larry" Thibault

We just became aware of the passing of Dr. Lawrence “Larry” Thibault back on September 10, 2011. He was well know as a biomechanics expert witness for the plaintiffs in propeller strike cases.

Dr. Thibault, a former Chairman of the School of Bioengineering at the University of Pennsylvania, and founded Biomechanics, Inc. at Exton Pennsylvania. As Biomechanics Inc. he represented many propeller accident victims or their survivors. Read More→

0 Categories : Propeller Safety News

A paper by Thiago Teixeira and Andreas Savvides from Yale and Gershon Dublon of the Massachusetts Institute of Technology surveys methods used to detect the presence of humans. This work could be very useful for those designing virtual propeller guards (propeller guarding technologies based on sensors).

The paper, A Survey of Human-Sensing: Methods for Detecting Presence, Count, Location, Track, and Identity, creates a taxonomy of observable human properties and physical traits (what can be sensed to detect human presence) along with the methods that can be used to detect them. The paper is available online sometimes.

Their work is a considerable enlargement of the work done by a European college student we helped back in 2005, Human Body Detection Methods: A Literature Review.

The current researchers also discuss the use of sensor fusion (the use of multiple types of sensors in the same system) to reduce false positives and improve overall accuracy. We first encouraged the use of sensor fusion in virtual propeller guards in response to an April 2002 NASA article discussed on our Technologies <2011 page. Brunswick later followed by suggesting the use of multiple sensor types in their infrared virtual propeller guard patents by Staerzl (U.S. Patent 7,476,862 and U.S. Patent 7,511,276). Read More→

0 Categories : Guard Technologies

Prior to mid 2011 we captured technologies with potential applications to virtual propeller guards (sensor based guards) or to conventional boat propeller guards on our Technologies page, now titled Prop Guard Technologies <2011. With the advent of our new site, we are moving future posts of this nature to their own category which we are launching today (March 25, 2012). Our earlier information on potential Propeller Guard Technologies will remain on the old <2011 page. Some of these technologies may have application to other guarding applications as well. [caption id="attachment_4273" align="aligncenter" width="614" caption="Vlist Propeller Safety Project. Eindhoven University of Technology. Netherlands. 2005."]Vlist Propeller Safety Project[/caption]

0 Categories : Guard Technologies

The Storm Lake Iowa Laass v. Brunswick case has focused attention on boats and marine drives striking submerged or floating dredge pipes / dredge lines. In the Storm Lake accident, a ten year old boy, David Paul McFarlin was killed on May 31, 2010. A 175 HP Mercury outboard struck a submerged dredge pipe, flipped back up into the boat, and the boy was killed by its propeller.

We started looking for a list of similar “struck dredge pipe” accidents and were a bit surprised not to find any such list. We thought it might especially exist over in the dredge safety literature, but found no such list there either. We found some dredge safety studies, but they focused on the safety of dredging employees, not boating safety.

In the absence of a list, we started making one ourselves. Earlier, when we started making a list of outboard motors that had flipped into boats, we jotted down several U.S. Coast Guard Boating Accident Report Database (BARD) accident numbers for dredge pipe strike accidents. We went back and fleshed out those accidents into a spreadsheet format including the basic statistics surrounding those accidents.

We also checked some media (news) reports, boat forums, and other online sources for additional boat or outboard motor or stern drive struck a floating or submerged dredge pipe accidents. We found almost countless reports online, but few of them are well documented, so we left them off our list. It looks like these accidents happen much more frequently than they are reported to BARD.

The spreadsheet below summarizes our findings. You can download a pdf of the spreadsheet that includes additional columns of data by clicking on it. It is best viewed on a 24 inch or larger monitor.
Read More→

We attended the 2012 Tulsa Boat Show on Saturday morning February 4, 2012. While still getting used to my new digital camera, Lora and I walked around and shot photos of propeller warning decals. I am well aware there is quite a bit of variety in propeller warning decals, but found an even broader selection at this show than I would have anticipated. We show some of them below, as well as some other warning labels seen at the 2012 Tulsa Boat Show.

The comments below are NOT an analysis of boat propeller warning labels. They are just our quick observations of some of the variety seen in propeller warning labels at a single boat show. We are not saying any of the labels are better or worse than others. We are just saying they are different. We continue to encourage the industry to adopt ANSI Z535 standards for boat propeller warning labels.

Propeller Warning Decal with Ladder

Propeller Warning Decal with Ladder

Many propeller warning decals are used in conjunction with the boat boarding ladder as shown in the Brunswick Bayliner boat ladder example above. We talk further about Brunswick’s use of a Danger label instead of the typical Warning label later in this post. Read More→

2 Categories : Legal Shorts