Our Earlier Propeller Safety Inventions

We created this Propeller Safety Inventions category in August 2011. I am listing some of our earlier inventions and linking to them here. We will be posting our future inventions in this category.

If PGT<2011 is beside the invention, more can be read about it on our Pre 2011 Propeller Guard Technologies page at the date provided. Some are thoroughly described, others are just briefly mentioned.

PGIC Inventions

  • Stealth Propeller Guard (we now call them Virtual Propeller Guards.) 1997. Further refined in our 20 April 2002 Virtual Propeller Guard Terminology page.
  • Fouling the Propeller on Purpose. 30 June 2005 PGT<2011.
  • Sense Capacitance of People in the Boat to Detect Man Overboard Situation. No date PGT<2011.
  • Detect Splash of People Falling Into the Water. Based on July 22-23, 2006 Wall Street Journal article. No date PGT<2011.
  • The Flapper (Rear screen of propeller guard swings up under way). Also see 13 October 2006 PGT<2011.
  • Detect Fright. 6 July 2007 PGT<2011.
  • Detect Screams. 6 July 2007 PGT<2011.
  • Use of Trim Cylinder Trailout Devices to Reduce Impact to Humans and to Protect Propeller Guards. 17 August 2007 PGT<2011.
  • Man Overboard Detection Without the Use of Lanyards or Tags. 1 August 2008 PGT<2011.
  • Doorbell Enforces Use of Stern Lookout on Larger Vessels. 1 August 2008 PGT<2011.
  • Propeller Guards Made From Nets. 2 February 2009 PGT<2011.
  • System for Reducing False Alarms in Virtual Propeller Guard Systems Using Infrared Sensors. 2 February 2009 PGT<2011.
  • Propeller Guard With Reduced Drag. Also see 2 February 2009 PGT<2011.
  • Self Adjusting Backup Alarms. (Backup alarms for vessels like houseboats that automatically adjust their sound level based on ambient noise levels.) 21 August 2009 PGT<2011.
  • Reverse Safety Propeller. (Safety propeller that works in reverse AND safety propeller that works in both forward and reverse.) 30 November 2009 PGT<2011.
  • 3D Propeller Screen (Use of multiple more open screens). 7 December 2009 PGT<2011.
  • Circle of Death Propeller Accident Invention. Posted 17 June 2010. Also see 24 July 2007 PGT<2011.
  • Virtual Propeller Guard based on detecting the absence of water. 20 June 2011 PGT<2011.


  1. regarding the safety propeller invented by colin chamberlain, australia, do you know if this product is yet in manufacturing? there was talk about it in 2010 where colin said he was looking for a manufacturing company to take up his design and put it on the shelves, however i am unclear as to whether or not this occured.

  2. The Australians are still working their way to market. Late last year PowerTech! showed a similar propeller at IBEX 2012 and won an innovation award. There may be some disputes between the two groups because the PowerTech! Safety Prop has since vanished from the press.

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