Life Saving and Fire Safety Research


Project 11011 - Daytime Distress Signals Effectiveness report

Authors - Lewandowski, M. J., Murphy, E. A., Reubelt, V. A., Steinhaus, M. K.

Report Date – December 2019

Abstract - This report details work on behalf of the Coast Guard Office of Design and Engineering Standards, Life Saving and Fire Safety Division (CG-ENG-4) to determine the daytime efficacy of an electronic visual distress signal, particularly as a comparable alternative to pyrotechnic flares, for recreational vessels in the United States (US). The Office of Search and Rescue (CG-SAR) and the Office of Boating Safety and Auxiliary (CG-BSX) played a major role in helping frame the desired test objectives. The report presents methods and results of field tests comparing conspicuity of hand-held flares, an orange distress flag, a signal mirror, human hand-waving, and a flashing, light-emitting diode (LED) signal. The LED signal characteristic is a group alternating, cyan (Cy) and red-orange (RO) color, 4 Hertz (Hz) flashing the SOS pattern at 50 candela (cd) effective intensity, as recommended in earlier work.

The project team conducted two full-scale field tests that yielded 759 human subject ratings of distress signal conspicuity at a one-half mile range. Test results varied greatly between sunny and cloudy conditions, with observers rating almost all signals as more conspicuous in cloudy conditions.


Key  Words

Visual Distress Signal Device (VDSD), maritime distress signal, Light-Emitting Diode (LED), alternative to pyrotechnic flare, conspicuity, daytime visibility, boating safety, search and rescue, lifesaving and fire safety


Distribution – Approved for public release; distribution is unlimited


Project 1103 Enhanced Person in the Water Detection report

DTIC link:

Author - J. Connelly

Report Date - February 2020

Abstract - A persistent challenge of the Search and Rescue mission is the difficulty of finding a person floating in the open ocean, waiting for rescue. The conspicuity of a floating person is a statement of how well that combination of person and floatation device is noticed by a human observer. This project focused on improving the detectability of a person in the water and used a subjective but quantifiable assessment of conspicuity to achieve a rank ordering process. That process was then applied in the down selection of prototypes solicited from the public in a prize challenge for improving detectability.

The primary activity of this project was the three-phase execution of a DHS S&T-sponsored prize competition; “U.S. Coast Guard Ready for Rescue Challenge.” Phase I sought to cast a wide net for novel but practical concepts for improving detectability. If new options became available for reasonable cost, comfort, and usability, then rescue at sea could be a more manageable problem. The Phase II judging panel down selected the list from Phase I by identifying prototypes that could be developed further using available prize competition funding. Phase III included an evaluation in an open water field exercise.

This effort demonstrated the value of running prize competitions to foster innovative design solutions that can help reduce mariner risk with low-cost PFD enhancements. In addition, the conspicuity testing results related to patterns, colors, and intensities add to the existing body-of-knowledge and provide a framework that the Office of Design and Engineering Standards, Lifesaving and Fire Safety Division (CG-ENG-4) can use to monitor commercial product advancements that support Search and Rescue.


Key Words - Maritime Search and Rescue, Conspicuity, Detection, PIW, Person in the water, safety at sea, Ready for Rescue Challenge, drowning, RF reflectivity, maritime lights at night, Thermal signature in maritime environment, Distress signals, LED, Visual Distress


Distribution – Approved for public release; distribution is unlimited