If you are interested in additional references in specific areas, please contact Polson Enterprises.
Parra's Marine Biological Sensing Research
Jorge Parra did extensive work in the area of detecting biological signals in water. Perhaps his work on detecting presence by detecting biological signals (cardiological, skeletal and respiratory noises) could be utilized to detect people near propellers. U.S. Patent 5,146,208 does an excellent job of presenting his research in this area. His patents (not all of which are still active) include:
- 5,031,637 Non-invasive diagnostic method and apparatus
- 5,099,455 Passive acoustic aquatic animal finder apparatus and method
- 5,146,208 Method and apparatus for detecting intrusion into a body of water
- 5,168,471 Integrated passive acoustic and active ultrasonic marine aquatic finder system
- 5,168,473 Integrated passive acoustic and active marine aquatic apparatus and method
- 5,168,474 Acoustic marine aquatic life detector with resonance chamber
- 5,255,685 Acoustic diagnostic apparatus with scan control
- 5,313,556 Acoustic method and apparatus for identifying human sonic sources
Other Biological Sensing Efforts
- Noncontact and noninvasive microwave biological measurements. Misawa, Kutsumi, Tada, Kim, Nakai, Miyabo, Hamada, Arai, Suzuki. Journal of Cardiology. 1990. Vol.20 No.1. Pgs.209-216. Abstract available from PubMed. Doppler sensors detected
heart signals from individuals wearing clothes. Band-pass filters were used to remove patients motions and respiratory motion.
- The Army has developed an "Acoustic Monitoring Pad" for field medics use in detecting heartbeat and lung sounds. The device is small fluid filled pouch with a hydrophone in it. When placed on a body, it does an excellent job of coupling the body's sounds in a field environment.
- An ESD (Enclosed Space Detection) System developed at Oak Ridge Federal Laboratory assists security and law officials in determining if an individual is hidden in an enclosed space such as a car, truck or shipping container. The individual's heartbeat shock wave or ballistocardiogram results in small, but detectable movements of the surface of the vehicle which are detected by the device.
Ambient Noise Imaging
- 5,333,129 Acoustic imaging in the ocean using ambient noise
Patent includes several references to this technology and is assigned to Univ of CA at Oakland. The technology involves
using the background noise already present in a body of water to image objects.
- 5,694,653 Water control sensor and method
Capacitance sensor for a faucet. Patent includes excellent background materials on this application.
- 5,155,707 OMNI-Directional Hydrophone
Special hydrophone and mounting method for attaching it to a vibrating structure (such as a marine drive) and canceling drive noises while allowing detecting other noise sources. This is a US Navy Patent.
- Dolphin Phone
Economical commercially available hydrophone for listening to dolphins.
Aquatic Wildlife Detection Sensors
- 5,450,063 Bird avert system
Microwave systems detects birds about to land on polluted water and scares them away.
- 5,307,052 Bio-amplifier for sensing the
bio-electric field of fish
Bio-amplifier detects and amplifies ventilation (breathing ) of fish.
- AWARE sonar is being tested to whale detection to avoid ship impacts at the Ocean Technology Center in Narragansett RI.
- Fish Stock Assessment Using a Horizontally Steered Parametric Sonar. Vaccaro, Christian and Novick. Oceans Conference Record (IEEE). Proceedings of the 1995 MTS/IEEE Oceans Conference Part 2 of 3. Oct. 9-13, 1995. Pgs. 265-271.
Discusses use of horizontal looking sonar.
- Automatic system for monitoring fish passage at dams. Castignolles, Cattoen and Larinier. Proceedings of SPIE - The International Society of Digital Image Processing XVII Jul 26-29 1994. v 2298 1994 San Diego, CA. Pgs. 419-429.
Video system both counts fish and recognizes them by species.
- 5,603,287 Animal sensing and repelling system
Senses dogs and cats in your yard. Turns on light and sprays them with water.
- Passive Acoustic Sensor System for Marine Mammal Detection
A 1998 Navy SBIR award. Passive acoustic sensor is developed from sonobuoy technology.
Marine Mammal detection sensors.
Fish Farm Security Systems
The patents below can be found in the Worldwide Patents section of the European Patent Office
- WO9001758 (World Organization Patent) Security System
System detects boats, divers, seals and poachers attempting to loot fish farms.
- GB2268266 (Great Britain Patent) Fish Farm Cage Security System
Detects seals and intruders at fish farms.
- AU4349893 (Australian Patent) Fish Farm Cage Security System
Australian version of the Great Britan Patent above.
Other Military Sensors
- 4,349,897 Bistatic Doppler underwater intrusion detection system
Bistatic sonar detects waders, swimmers and others entering the protected zone. Patent is assigned to US Navy.
- PADD Portable Acoustic Doppler Detector
Detects surface and underwater swimmers.
- Aquamesh Fiber optic armed underwater security barrier.
Detects underwater intruders.
- EAST Environmentally Adaptive Sonar Technology
The Office of Navy Research is working with the University of Washington to study the effects and problems of deep water
sensors in shallow noisy waters.
- 4,780,085 Lap Timing Device
System for timing swimming laps includes ultrasonic proximity sensor to detect completion of each lap.
- 5,369,269 Human Body Detection System
Infrared detector assigned to Mitsubishi
- 5,712,623 Small-sized alarm device
Device hangs on a door knob and sends an alarm when someone approaches the door knob.
- 5,724,024 Device for Detecting presence of persons on seats
Detects breathing and/or heart beat
- 5,760,688 Body Sensing Device
Oscillator discriminates between humans an inanimate objects
- Technology for pyroelectric sensors detects human motion. Yamamoto. JEE. Journal of Electronic Engineering (Japan). Vol.32. No.344. Aug. 1995. Pages 19-21.
Active and passive sensors detect human motion by sensing small amounts of infrared radiation generated when people move.
- Sensor array for human-body detection based on pyroelectric polyvinylidene fluoride. Freitag and Meixner. IEEE Transactions on
Electrical Insulation Sixth International Symposium on Electrets. Sep 1-3 1988. Vol.24 No.3. June 1989. Oxford England. Pgs. 469-472.
PVDF sensors can determine presence, distance and direction of movement. This work is being done by Siemens AG.
- Synergistic Radar: Novel applications and performance. Gagnon and Frechette. IEEE Annual International Carnahan Conference on Security Technology. Proceedings of the 28th Annual 1994 International Carnahan Conference on Security Technology Oct 12-14 1994 Albuquerque NM. Pgs. 26-30.
Detects movement of humans by monitoring disturbances to commercial FM radio signals. A marine drive might actually be
used as an antenna sensor.
- IR sensor using functional semiconducting fiber and application to human detection. Muto, Misyayama, Yanagida, Kajiwara, Mori, Imai, Harada and Ichikawa. Electronics & Communications in Japan. Part II. Vol. 74 No.9. Sept. 1991. Pgs.104-116.
Development of a fast response infrared human sensor.
- Human presence detection by capacitive proximity sensor. Buck and Aherin. Applied Engineering in Agriculture. Vol.7 No.1. Jan 1991. Pgs.55-60.
Capacitive sensors used to detect humans even when covered with water or mud in Agricultural applications. Prototype has range
of 20 cm. This work was done at the Univ. of Illinois in Urbana.
- Shorrock Electronics Systems 810 T-Line System.
Capacitance sensor works as two wires which are excited by low radio frequency. When the signals are disturbed, the disturbance is compared to the signature of a human disturbance to reduce false alarms.
- The charge transfer sensor. Phillipp. Sensors. Nov. 1996.
This sensor uses broad spectrum signals to make ordinary objects (marine drives??) proximity sensitive. The sensor described if from Quantum Research.
- SmarTek Systems Passive Acousic Sensors
This solar powered sensor detects vehicles by sound.
- The Basic Principles of Microwave Proximity Sensing. Sensors. May 1991.
Describes the ruggedness of Microwave sensors and displays an example of a unit used to sense pedestrians in a rail road yard.
- Perimeter Security Sensor Technologies Handbook frrom
the National Law Enforcement and Corrections Technologies Center (NLECTC) does a great job of describing in depth the sensors frequently used in security applications.
- Desert Star Systems
Systems to sense position and location of divers.
New Sensors Encountered After this Paper was Published
- Radar and sterovision used by Pittsburgh Port Authority and Pennsylvania Dept. of Transportation to alert metro bus drivers
a person is near the bus. CCD images are examined for human "signatures". See Photonics Spectra. June 1999. Page 100. Could a very similar application indicate the presence of people in the water near a propeller?
Signal Conditioning in Noisy Environments
Conventional Propeller Guards
See the recent US Coast Guard study,
"Propeller Injury Protection, an Evaluation of Commercially Available Protection Devices"
A recent patent of note is:
5,759,075 Propeller Guard
- 3,889,624 Retractable Propeller Guard for Outboard Motor or Stern Drive Unit. 1975. Donald G. Balius.
- 4,078,516 Propeller Guard. 1978. Donald G. Balius.
- 4,106,425 Marine Propulsion Unit with Protected Screw. 1978. Ludwig Gruber, Freilasing. (Germany)
- 4,411,631 Propeller Guard. Eero Makinen, Espoo and Stefan Gordin. (Finland)
- 4,304,558 Marine Propulsion Device Including Propeller Shroud. OMC
- 4,565,533 Boat Propeller Guard. 1986. Manford H. Springer.(Canada)
- 4,826,461 Propeller Protector. 1990. Brunswick.
- 4,957,459 Propeller Shroud with Load Bearing Structure. 1990. Brunswick.
- 5,009,620 Propeller Guard. 1991. Louis Feranda, Sr.
assigned to PropGuard. I visited with them at IMTEC98 and found them
very devoted to improving water safety. They also showed me a prototype of a small pager sized device that could
be worn by swimmers to allow them to be detected near the propeller. Their product brochure included prop strike
statistics and a medical study of those injured.
Interesting Propeller Devices
These units do not fit the conventional propeller guard category, but have some implications in that area.
- 5,238,432 Marine drive unit impact avoidance system
A "wand" precedes the drive. If it hits something, the drive swings up without the object actually hitting the drive.
- JP5310188 (Japan) Safety Device for Small Ship
A "net type" prop guard swings out of the way at high speeds, but comes back over the prop at low speeds, specifically to
- The US Coast Guard Boating Safety Federal Register Page has a link
to several Coast Guard attempts to gather public comments on propeller injuries. Especially those involving rented boats and
- 1995 & 1996 U.S. Coast Guard Boat Accident Statistics
- Motorboat propeller injuries. Mendez-Fernandez. Annals of Plastic Surgery. Aug. 1998. Vol.41 No.2. Pgs. 113-118.
Experience with nine propeller injuries are presented.
- Propeller injuries. Mann. Southern Medical Journal. Vol.69 No,5. May 1976. Pgs.567-569.
Information on nine cases and bacteria problems are discussed.
- Propeller injuries incurred in boating accidents. Mann. American Journal of Sports Medicine. Vol.8 No.4. Jul-Aug 1980. Pgs.280-284.
Information on 32 cases are presented. Bacteria, salt water and contamination are discussed.
- Study of Boat and Boat Propeller-Related Injuries in the United States, 1991-1992. National Center for Injury Prevention and Control and U.S. Coast Guard. Available from NTIS.
- A study of boat and boat propeller-related injuries in the United States, 1991-1992. Branche-Dorsey CM,
Smith SM, Johnson D.Washington, DC: US Department of Transportation, US Coast Guard, 1993
(report no. CG-D-12-93).
- Motorboat Propeller Injuries [monograph]. Vernick, J.S. and Associates. The Johns
Hopkins University and the Institute for Injury Reduction, Sept 1992.
- Motorboat propeller injuries in Wisconsin: enumeration and prevention. Hargarten, Karlson, Vernick and Aprahamian.
Journal of Trauma. Vol.37 No.2. Aug 1994. Pgs.187-190.
- Outboard motor propeller injuries. Kutarski. Injury. Vol.20. No.2. Mar 1989. Pgs.87-91.
Seven cases are examined from a medical standpoint.
- Boat-propeller related injuries - Texas 1997. JAMA Vol.279 No. 23. Jun 1998. Page 1858.
Background data is online.
Additional info on the same study
is available in the Vol.47 No.17. May 8, 1998 issue of Morbitity and Mortality Weekly Report.
- Motorboat propeller injuries. Price and Moorefield. Journal of the Florida Medical Assoc.Vol.76 No.4. June 1987. Pgs.399-401.
- Causes and mechanisms of surgical care in propeller injuries. Sabol. Acta Chir Iugosl. 1977; 24 Suppl 2:331-9.
- Speedboat propeller injuries. Sleight. British Medical Journal. 1974 May 25;2(916). Pgs.427-428.
- SPIN Stop Propeller Injuries Now
A group promoting propeller safety
Propeller Injury Lawsuits
Typical cases involving propeller injuries include:
- FITZPATRICK v. MADONNA and Outboard Marine Corp, Appeal of OUTBOARD MARINE CORPORATION. 623 Atlantic Reporter 2nd Series, pgs. 322-327.
- PREE v. The BRUNSWICK CORPORATION. 983 Federal Reporter 2nd Series (8th Cir. 1993), pages 863-868.
- WOLTERING v. OUTBOARD MARINE CORPORATION. 615 North Eastern Reporter, 2nd Series, pages 86-89.
- FARNER v. BRUNSWICK CORPORATION. 607 North Eastern Reporter, 2nd Series, pages 562-568.
- CALABRO v. OUTBOARD MARINE CORPORATION. 599 Southern Reporter, 2nd Series, pages 717-718.
- HIGHTOWER v. COX. 418 South Eastern Reporter, 2nd Series, pages 613-616.
- MOORE v. BRUNSWICK BOWLING & BILLIARDS CORPORATION, MERCURY DIVISION. 853 South Western Reporter 2nd Series, pages 842-850.
- BEECH through BEECH v. OUTBOARD MARINE CORPORATION. 584 Southern Reporter, 2nd Series, pages 447-450.
- ELLIOTT v. BRUNSWICK CORPORATION. 903 Federal Reporter, 2nd Series, pages 1505-1510.
- SHIELDS v. OUTBOARD MARINE CORPORATION. 776 Federal Supplement pages 1579-1583.
- MOWERY v. MERCURY MARINE, DIVISION OF BRUNSWICK CORPORATION. 773 Federal Supplement, pages 1012-1018.
In Ryan v. Brunswick
the Michigan Supreme Court affirmed: 209 Mich App 519; 531 NW2d 793 (1995).
Another version of the case report is online in
The recent Lewis v. Brunswick suit involved an Oklahoma teenage girl who fell into the water and was fatally injured by a propeller. The decision in favor of Brunswick was upheld in the 11 Circuit and the family pushed the case to the Supreme Court. The case was settled for an estimated $700K (probably small in terms of the legal expenses) but sets a new precedent for Brunswick which has not backed down from a prop suit. Perhaps they felt the court was about to reverse their longstanding defense? This case should particularly interest boat builders in new methods of protecting people in the water.
Several legal consultants specialize in this area, one of them, Mr. Tom Ebro maintains a web site called
Aquarisk. On that site he maintains a list of prop cases I am reproducing
below. His brief descriptions provide some insight into the types of situations propellers injure people.
||Coral Gables, Florida
||Rendall v. Karabas
||Foot severed by boat's propellers
||Occupants were ejected and struck by boat
||Baton Rouge, Louisiana
||Evans v. Bennett
||Occupant fell overboard and was run over
||Levin v. Bates
||Inattentive boat driver ran over a fallen
||Key West, Florida
||Calabro v. Burgess
||Raceboat collided during race; prop injury
||Cole v. Eubanks & Manatee County
||Boat ran over a skindiver; leg was amputated
||Redmon v. Carr
||Boarding waterskier sliced his leg on prop
||New York, New York
||Schenck v. Walt Disney World
||Ferryboat ran over a patron in rental boat
||Koble v. Tabor
||Swimmer was run over by a boat *Fatal
||Meyer v. City of Clearwater
||Boat ran over a swimmer close to buoys
||Stamper v. Goldring/Hewes
||Boat without kill-switch ran over the driver
||Costa Mesa, California
||Riley v. Zodiac of North America
||Boat ran over ejected driver, prop injuries
||Raines v. Renken Boat Manufacturing
||Boat without kill-switch struck ejected
||Kavezadeh v. Zodiac of France
||Prop injury, woman fell overboard off pontoon
||Caban v. Walt Disney World
||Prop injury, boy's arm mangled by propguard
||Ramsey v. Catfish Bay Marina
||Boat rental propeller laceration on fallen
||Karl Becker v. US Marine
||Boat's sharp turn threw passenger, cut by
||Higgins v. Ocean City Amusement Park
||Small skeeter boat flipped, passing propeller
Airplane propellers provide a pretty direct airborne analogy to marine propellers.
- 5,074,488 Aircraft engine deactivation apparatus
Sensors detect people near propellers or jet intakes and brakes are used to stop the units.
- An Analysis of Civil Aviation Propeller-to-Person Accidents: 1965-79.Collins, Mastrullo, Kirkham, and Grape. Aviation, Space,
and Environmental Medicine. May 1982. Pages 458-462.
- Review of Civil Aviation Propeller-to-Person Accidents: 1980-1989. Collins. Published January 1993. 10 pages. Available from NTIS.
Devices to Locate People for Water Rescue
- 4,305,143 Automatic man overboard sensor and rescue system
Transmitter worn by person, activates upon hitting the water.
- 5,408,238 Location of overboard person or object or of water-chemical interface
Floatable object containing signal broadcasting means is thrown near the person or object.
- 5,597,335 Marine personnel rescue system
Autonomous or semi-autonomous marine vehicle searches for persons in distress by using video, thermal and audio sensors
Other Rescue Situation Body Detectors
- PL164169 (Poland Patent) Method of and apparatus for performing rescue searching, in particular for detection of person buried as result of landslide
- Mobile microwave sensor for detection of trapped human beings. Aggelopoulos, Karabetsos, Constantinou and Uzunoglu.
Measurement: Journal of the International Measurement Confederation. Vol.18 No.3. July 1996. Pgs. 177-183.
Trying to design X band microwave to detect human movement (heartbeat and breathing) of people trapped behind rubble or obstacles.
- 4,331,957 Transponder for use in locating avalanche victims
Victims must wear a reflector.
- 4.850,031 Avalanche victim locating apparatus
Individuals wear a light sensitive triggering device that begins transmitting when buried in snow.
Swimming Pool Monitors
Propeller Guard Articles
- Prop Guards prevent injuries. Dr. Robert A. Warren. Expertise, Inc. Boat & Motor Dealer. Nov. 1999. Pg. 44.
- Prop guard regulations may be coming. Bob Duke. Boating Industry International. June 2000. Pgs. 36-39.
Coast Guard & Industry Meetings
- Report of the Propeller Guard Subcommittee. The National Boating Safety Advisory Council. Presented Nov. 7, 1989.
Some Suggested System Design Parameters
- Totally self contained - nothing required to be worn by people in the water
- Detect presence of humans partially or totally submerged within 6 feet of a stationary or rotating marine propeller
- Does not give false signals due to waves, prop exhaust, fish, drive noise, boat noises, noise from people on the boat, fixed objects (piers, docks, dock bumpers) that may be present at takeoff.
- Provides a signal within .25 second of an individual entering the protected zone.
- Requires minimal electrical power (12 volt or internally supplied or solar powered)
- Durable and packaged for a water and or salt water environment
- Sensors not effected by algae, barnacles and other marine growth
- Normal life exceeding 5 years when used in a normal recreational boat
- Means of mounting the device to avoid boat drag when underway.
- No boat or drive modifications required
- Means of testing it (like smoke detector push button)
- Provides indication it is "on"
- Means of transmitting signal from device to the alarm
- Detects people in wet suits
- Detects people with air tanks
- Not effected by murky water
- Detection is not effected by rain
- Not effected by surf
- Not effected by reflections from shallow bottom or the waters surface
- Minimal false alarms
- Does not attract fish to the propeller area
- Lightweight and small
- Cost - low enough for people to feel it is of great value for the service it provides
Patent Classes and Search Words
International Patent Class B63H 005/16 and U.S Patent Class 440/72 cover traditional propeller guards.
US Patent Classes 340/565 and 340/573 contains many of the sensors of interest. International Patent Class
G08B 013/00 also contains some related sensors.
Some search words we found especially useful in the various databases and search engines while researching this
- intrusion, intruder
- detect, detector, detection
- human proximity sensor
- shallow water
- swimming pool
- littoral (coastal waters term used by military)
- propeller strikes
- propeller guard
- marine mammal
- diver, scuba, frogman, Navy Seal
- fish sensor, locator, detector
- human, person
- man over board, MOB
- ESDS (Enclosed Space Detection System)
- injury, injuries
- bistatic sonar
- bistatic doppler
- ANI (Ambient Noise Imaging)
- ADONIS (Acoustic Daylight Ocean Noise Imaging)
- passive acoustic
- background noise
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