Seamanship & Navigation, July 2021
Handheld distress signaling
Being seen is critical to being rescued. Even if you are equipped with a modern EPIRB that can get rescuers very close to your position, the rescuers still must see you to pick you up. This can be challenging when weather conditions are extreme, it’s nighttime, or if a rescue aircraft or ship has limited on-scene loiter time.
A person overboard faces a rescue dilemma similar to that of a crew of a sinking boat, even if it occurs from a slow-moving vessel. At six knots a boat covers 200 yards, or 600 feet, every minute. If it takes a boat five minutes to stop and turn around, then a victim will be 1,000 yards — half a mile or more — away from his or her rescuers.
Therefore, to find and rescue a group or individual takes a combination of factors:
• Accurate reporting of the initial position and time of an incident.
• Continuous contact and updates on position.
• Easily seen or detected locating signals.
Locating signals can be categorized as electronic, visual, or aural, and the best odds of being rescued include using a combination of all three. Traditional methods of rescue have relied on the receipt of an initial Mayday message and then the use of flares for indicating the distressed party’s final location once rescue arrives. Success is weighted on an accurate initial distress position being heard by a responsive rescue agency. Once a distress message is received, then attracting attention of potential rescuers rests with knowing the capabilities and limitations of signaling equipment and their proper use.
Electronic, visual and sound devices are of three types:
Autonomous: These work when unattended and for long periods. Examples are EPIRBS, AIS transponders, strobe lights, radar reflectors, life rafts, survival suits, inflatable gear.
Manual: Often long lived, these require human input. Examples are signal mirrors, flashlights, whistles, foghorns, balloons, kites, night-vision scopes, and flags.
Short duration: for use when rescue units are nearby. Examples are flares, smoke, sea dye, and chemical sticks.
We’ll focus on handheld and non-RF devices here. Signal mirrors are probably the most reliable and simple of signaling devices. Under normal sunlit conditions, mirror flashes can be seen for 10 miles, with reports of flashes seen at 50 miles and an actual rescue attributed to a flash seen at 105 miles. Signal mirrors come in various sizes and are constructed from glass as well as stainless steel and plastic. Glass is a preferred choice since it has the best reflectivity and does not dull or scratch. A CD or DVD disk can also be used as a signal mirror in a pinch.
Two features are needed to make a signal mirror useful: an aiming hole so reflected light can be aimed and a lanyard attachment so a mirror cannot be lost overboard. Survival guides recommend a mirror for each person, which is prudent should individuals become separated.
This precaution also allows survivors in a raft to send signals in multiple directions simultaneously. Quality glass mirrors have been reported to reflect bright moonlight, making them useful day and night.
Next on the list of simple and reliable signaling devices are chemical light sticks. These personal marker lights generally have a duration of roughly five minutes (high intensity) to 12 hours and come in an international orange, the accepted distress signaling color. Tests show these lights are visible up to one mile and are seen most easily when swung by their lanyards.
Strobe lights are a step up from chemical lights in brightness, often capable of being seen at five miles, but they require batteries and have switches that must be checked and prevented from being accidentally turned on. Strobes are not always as visible from overhead as they are when viewed horizontally due to bulb orientation, so they should not be depended on for airborne rescue. Swinging a strobe on a lanyard might be needed to attract the attention of a helicopter or airplane crew.
Whistles and horns are important and often underrated signaling devices. Their sound carries much farther than a human voice — often up to two miles –– and it is less tiring to blow a whistle than to shout over the background noise of wind and sea. Three short blasts on a whistle (the international code for distress) are more likely to heard by potential rescuers than a voice.
Sea dye marker creates a bright green stain on the water when released, but it is short-lived (less than an hour), caustic and not visible at night. As an alternative to sea dye marker, See/Rescue Corp. sells a 40-foot, bright-orange plastic ribbon that floats. This ribbon has been tested and approved by the US. Navy as a substitute for sea dye marker. Stiffeners keep the ribbon open and prevent it from becoming twisted, making it useful both in the water and on a boat’s deck.
Flares, kites, and balloons are all forms of serial distress signals. A product called Sky Alert (available from Landfall Navigation) is a good example of this category. Sky Alert is a bright international orange kite-parafoil that flies in five knots or more of wind. It develops sufficient force in eight knots of wind to lift and hold aloft an emergency radar reflector or strobe light. Sky Alert has been certified to meet U.S. Coast Guard requirements for distress signals. Though not a replacement for flares, Sky Alert does have unlimited “hang” time provided you have the minimum five knot breeze.
Shooting a firearm will also attract attention should you have one available. With this type of signaling, of course, you should be very aware of not aiming anywhere near a rescue aircraft. A firearm might prove further use in harvesting sea birds should you be in for a prolonged stay.
Flares, the signaling standby, come in four different types:
• Parachute rocket
• Multi-star rocket
• Buoyant or hand-held orange smoke
Safety of Life at Sea (SOLAS) flares are the best, for they have the longest “burn” and “hang” times and are by far the brightest. However, flares and smoke signals burn for just one to three minutes maximum and so are truly only effective at pinpointing a position once a rescuer has, essentially, located a distressed party.
Life rafts, inflatable dinghies, and survival suits may not be thought of as signaling devices, but their size, orange color, and attached lights can all contribute to being spotted.