Boating Distress Signals

Boating Distress Signals, the latest in MOB electronic distress signals for today’s boater. This newsletter features some of the new boating equipment and technology to help you locate the Man or Woman overboard including

  • MOB tags
  • PLB,s
  • EPIRB’s
  • SART’s
  • PABs

Emergency Rescue Signaling devices


When looking at emergency electronic signal devices we can divide them up into 2 categories;

  • Signals sent to emergency rescue services.
  • Signals broadcast to the immediate vicinity.

Signals sent to emergency rescue services. These devices send signals over satellites and do not send a signal back to the vessel you fell off. EPIRBs and PLBs are for when you cannot rescue yourself and there is no one in the immediate area to help. Satellite messengers are a new generation of devices, run by private enterprise.


EPIRBs & PLBs; when activated send a signal to shore stations part of the COSPAS-SARSAT satellite system. These are official rescue devices and must be registered. EPIRBs are registered to a vessel while PLBs are registered to a person.

ACR resqlink


Satellite Messengers; A second group of long range devices include; the SPOT tracking device and also DeLormes inReach which are not just rescue devices they also allow you to send messages and your location, so friends can track where you are on Google earth.

Signals broadcast to the immediate vicinity. These devices send signals locally and do not send to SAR

VHF with DSC, VHF radio have a red button the DSC button which when activated send a digital signal indicating your position and MMSI number. For this feature you must have a GPS linked to the VHF and you must register it

MOB tags, Homing devices; These devices are localized and broadcast a signal which can be picked up by the mother vessel or anyone in the vicinity. These include a host of MOB tags , SARTs and the new AIS personal beacons. Raymarines LifeTag is an example of a MOB tag, They do not contact Search and rescue SAR

Phones; With an iridium phone you can call from just about anywhere in the world. With a cell phone and in close to land you can call for rescue, but these devices should not be relied on. The other devices send signals automatically with your position and identity through you MMSi number.

General discussion of distress signals

The first point to make about MOB and distress signals is that modern communications has changed everything. If you have someone fall overboard and they are wearing a MOB alarm, a signal will be triggered on the vessel and you will have a spot where they fell overboard. This is a system for crewed yachts and boats.

Second if you fall overboard with a PLB which has a GPS, a distress signal will be sent out on 406MHz to Search and Rescue (SAR) organizations. You can be found fairly quickly from pretty much anywhere in the world these days. PLBs are more appropriate for a single or short handed boats, where self survival is more important.

The days of being days or weeks adrift at sea are past as long as you take the adequate precautions. With an EPIRB with integral GPS which has been properly registered SAR can pick up your signal and know where you are and who you are. A seminar on liferafts that I saw outlined a big problem with modern communications devices and that’s water and dead batteries. Make sure you have a totally waterproof grab bag plus plenty of sources of batteries and backup power, like freeplay energy and power monkey, see electrical section for alternate energy supplies.

IMPORTANT NOTICE, SARSAT satellites will stop listening to 121.5MHz

Man Overboard Tags

Homing Devices

These alarms go of when the person wearing the tag or alarm leaves the vessel area i.e. falls overboard. There are two types of systems, one uses a direction finder homing device and the other uses a GPS signal.

First its important to realize when picking the equipment, that you need to know if the vessel will have someone aboard to come get you. If you are single handing or fishing alone you need a PLB or something that will kill the power to the engine.

A note about simple GPS MOB buttons on your instruments and you are in tidal waters. The spot the MOB went overboard is a GPS coordinate. The MOB victim would have moved from that position by wind and current so you need to factor in how much time has passed and the likely track they would have followed

RayMarine LifeTag

MOB life tag sends out a RF signal when the (up to 16) units go out of the30 ft range. The alarm goes of in the cabin and the position will be shown on any Raymarine multi function display. This is a Personal Locator Beacon (PLB). Not good for single handing as it does not send out signal to SAR (Search and Rescue).

Basic system cost $685 for two tags receiver and buzzer, must have Raymarine instruments to complete system. We will do a round up of all the offerings in the PLB department in the near future.


Active crew monitoring system, always connected, Immediate and automatic. Sends NMEA waypoint message from MOB to most chart plotters. Second relay to sound extra alarm / shut-off engine. Does not contact SAR organizations.

This is a GPS system so remember wind and tide. Now in US from Oceanmarketing.

Alert 2

MOB overboard signal, vessel to MOB signal. Does not contact SAR organizations.

This is a RF system. The ALERT 2 System consists of the Alert water-activated radio transmitter, which transmits a coded 418 MHz signal when immersed for one second, and the Alert receiver aboard your vessel, which triggers its audible alarm when it receives the transmitter signal. It can also plot a position on a compatible GPS or shut down the engine.

McMurdo MOB Guardian

The new system from McMurdo for 2007, the Guardian was co- developed by the RNLI. This is a bit of a cross over system. The crew wear active alarms and a signal goes off onboard when the transmitter strays beyond the boundaries, the alarm can be manually set off also. However additionally, if after a set period of time the transmitter is not turned off a signal is automatically sent to SAR organizations via satellite. Maybe the best of both Worlds we will have to see.


This type is more Power orientated. The power to the engines is gut off when the tag leaves the vessel are i.e. goes overboard. Especially useful for a fisherman alone or water-skier. $800 for twin outboard engine.

I think they may have something here!!!

PLB Personal Locator Beacons

Personal locator Beacons PLB’s transmit on 406mhz to SARSAT (explained left column. This is more for self preservation, i.e. if your single handed there is no crew onboard to come get you, or if the vessel sinks you will need a PLB or EPIRB.

PLB are pocket-sized emergency beacons, pocket sized version of the EPIRB (Emergency Position Indicating Radio Beacon) that boaters and pilots, respectively.

The most easily notable differences are size and cost. PLBs will fit in a pocket, weigh in at about a pound or so and they are expected to sell for prices starting as low as $550 initially.

ACR ResQLink

ACR ResQLink personal locator beacon PLB with Onboard 66-Channel GPS. The ResQLink activates easily. Just deploy the antenna and press the ON button. The all-new ResQLink™ Personal Locator Beacon is just about the smallest 406 MHz PLB in the world.

The Antenna is wrapped around the body and can be deployed easily with one hand. Once the antenna is deployed the two button (on/off and test) activation is accessible.

Feature packed, with three levels of integrated signal technology, GPS positioning, a powerful 406 MHz signal, and 121.5 MHz homing capability. Once activated the ResQLink™ 5 watt transmission relays your position to a worldwide network of Search and Rescue satellites.

ResQLink Personal Locator Beacon

Fastfind plus GPS


The Fast find is another recommended personal PLB with GPS. The unit must be registered to the individual Owner. and transmits on 406MHz. and has a 121.5 homing signal. Cost $550.

Fast Find 220

Sea Marshall

The Sea Marshall is a direction Finder system and was rated highly in the COB report see USPS upper left.Easily fitted into a lifejacket transmits on the International Search and Rescue Frequency of 121.5 MHz giving you the full support of your Local Search And Rescue Authority should your require extra assistance rescuing lost person. Transmission time average of 24 to 36 hours…for ore information download the PDF instruction manual. I am not sure with the notice above about 121.5 being phased out how this leaves Sea Marshall


Left column you will find the link to Equipped to Survive EPIRB review in 2005. Doug Ritter Euipped’s Executive director continues to make locating beacons better through his tests and pestering manufacturers. A good example is the Test on McMurdo beacons which did not shine in the tests in Key West. Since then McMurdo made improvements and now Sept 2006 McMurdo has signed a deal to supply the Coats Guard with FastFind Plus PLB’s.

GlobalFix™ iPro


The all new GlobalFix™ iPRO Emergency Position Indicating Radio Beacon (EPIRB) is the next generation in marine safety electronics. The GlobalFix™ iPRO is a breakthrough product that boasts a digital display and dual GPS technology. Available in Category I or II brackets.




The G5 SMARTFIND PLUS has all the advanced features of the standard E5 SMARTFIND with the addition of an integral 12 channel GPS receiver. The addition of a GPS receiver to the EPIRB ensures that the exact position of a casualty is relayed to the rescue services.

$750 for manual deployment or $900 automatic deployment. The list of type approvals for Smartfind are increasing and now include US, SA, Spain, UK, Canada, Chile, China and growing.

G5 SmartFind

SafeSea E100 EPIRB

Ocean Signal

new SafeSea E100 EPIRB from Ocean Signal was designed with the idea of the user being able to maintain battery use. Company, literature claims the E100 has the longest operational battery life in the industry, with the ability to operate continuously for four days.

The E100 features a 121.5 MHz homing beacon and an LED strobe light and is a Cospas-Sarsat device operating on a 406 MHz satellite band.

E100 EPIRB (price ranges from $519 to $649

Search and Rescue Transponders


Search and Rescue Transponders, allow search vessels or aircraft to locate you. Wikipedia description, Search and Rescue Transponder’s.

Search and Rescue Transponders


The Simrad SA50 SART – Search and Rescue Transponder – enables any rescue vessel or aircraft fitted with radar to locate and steer to your position, dramatically increasing your chance of rescue should the unthinkable happen.

As the smallest and lightest SART available today, the Simrad SA50 can be easily stowed, making it ideal for yachts and powerboats where space may be at a premium.

Personal AIS beacons

PABs are discussed here

Man Overboard Alarms

Autotether engine kill switch

If you are a boater especially a high speed boater, sudden changes of direction can throw you off the boat. Waves can also throw you overboard. The video below shows what happens when you fall overboard. The engine does not know you are gone and so the vessel is going to carry on until it gets a new command.

A very simple kill switch is a lanyard which disconnects from the engines kill switch when you fall overboard. The lanyard simply pulls the switch. Jet skis i.e. PWCs are required to have a kill switch and use a simple wrist lanyards that kill the engine when you fall off.