Emergency Marine Communications

Cruisers spend big dollars on emergency communications, and in most cases never use them. What are some of the options, their pros and cons, and use cases aboard?

Emergency Communication Options

EPIRB

EPIRBs (Emergency Position Indicating Radio Beacon(s)) are the gold standard in reliability and durability. Designed by an international consortium of search and rescue agencies in the 1980s, EPIRBs transmit a signal via the SARSAT (Search And Rescue Satellite Aided Tracking) system of satellites (a combination of government operated LEOSAR, GEOSAR, and MEOSAR satellites) in order to communicate with a network of 29 MCCs (Mission Control Centers) and national RCCs (Rescue Coordination Centers) around the globe.

When you activate your EPIRB, a SARSAT satellite will pick up the signal within minutes and relay it to the closest MCC via their Local User Terminal. The MCC will relay the transmission to the RCC in the country in which you have registered your EPIRB (typically your boat’s flag country). ‘Your’ RCC will then relay the information to the RCC responsible for the area you are in and reach out to the emergency contacts registered with your beacon. The RCC closest to your boat’s location will begin the rescue operation. This is typically done in less than an hour.

The downside of EPIRBs is that they are one-way communicators – they simply relay your call for help, and do not indicate if it’s a fire, sinking, or medical emergency.

Once purchased, EPIRBs are free to operate (no subscription fee), and the only ongoing cost is periodic replacement of the batteries (depending on unit specifications). Most units are water activated, so they should be stored where rain or spray won’t set them off inadvertently. They are specified to operate for a minimum of 48 hours, but will typically operate much longer.

EPIRBs must have the battery replaced after use, as they are good for a single activation per battery.

PLB

PLBs (Personal Locator Beacon(s)) are basically EPIRBs in short pants. Smaller and lighter than EPIRBs, they are typically less expensive as well. They broadcast at the same power as EPIRBs (5.0 watts) but have half the battery life (24 hours minimum vs. 48 hours with an EPIRB). As with EPIRBs, they will typically operate much longer than the minimum specified time.

Similar to EPIRBs, PLBs must be registered with a national authority and have no operating cost beyond periodic battery replacement.

PLBs must also have the battery replaced after use.

System components and relay path for an EPIRB distress message.

SEND

SENDs (Satellite Emergency Notification Device(s)) are devices such as the Garmin InReach, InReach Mini, and InReach Messenger; Zoleo; Spot and Spot X; Yellowbrick; ACR Bivy Stick; and Motorola Defy Satellite Link.

These devices use various commercial satellites or commercial satellite constellations and allow emergency ‘send help’ communications, typically with a dedicated SOS button. They also typically allow two-way communications, like a text or SMS on your phone. Some devices allow this in a self-contained method, while others require tethering with a smartphone or tablet. Most operate on the Iridium Satellite Network, which is generally considered to be of the highest quality and offers global coverage. Others use networks such as Globalstar, which does not offer global coverage. They typically operate at about 1.5 watts of transmit power.

Most SENDs use the IERCC (International Emergency Response Coordination Center) as their emergency response partner. Spot uses Overwatch Rescue.

When you press ‘SOS’ on one of these devices, it sends a message via the satellite or satellite constellation to the emergency response partner, who notifies the relevant authorities to begin your rescue. If your device allows, they will also call/text you back, and get in touch with your emergency contacts.

If the device allows you to send and receive messages, you can also initiate a two-way conversation with a shoreside contact for a serious but not life-threatening situation, such as an engine or medical problem.

Most SENDs also support the sending of ‘breadcrumb’ trails while cruising. This is useful to allow shoreside contacts to follow you and leaves a record of your journey. In the event that you ‘go dark’ in an emergency that incapacitates you and your crew and makes you unable to activate any of your devices, these ‘breadcrumbs’ will provide search and rescue teams a starting place to look for you.

Each of these devices, being commercial, requires a subscription. Costs vary.

SENDs are rechargeable and can be used again and again. Battery life varies between units. There is a good comparative review of many units here.

A variety of first generation EPIRB emergency locator beacons

DSC Distress Calls

Marine radios (both VHF and Marine SSB) can send a DSC (Digital Selective Calling) alert, usually by pressing a red button on the radio or its handset. Typically, the button must be held down for more than 3 seconds to activate it, so as to limit the chance of false alerts. Pressing the button sends a GPS position if your radio contains or is connected to a GPS, plus your MMSI (Marine Mobile Service Identity).

DSC calls on VHF are monitored worldwide (within coverage limits), but coverage via Marine SSB is spotty. There are propagation issues for SSB, and some rescue authorities no longer monitor the frequency. The USCG, for example, stopped monitoring the 2182Hz rescue frequency in 2013. VHF DSC alerts will be picked up by other vessels within radio range.

This service is cost-free once you have installed your radio. [Editor’s Note: If you are sailing in international waters, you will need to purchase an annual radio license from Innovation, Science, and Economic Development Canada (ISED). They will also issue you with a call sign, which may be needed when communicating with international Coast Guard services.]

What about Cell Phone Satellite Communications?

Some newer cell phones from Apple or Google/Pixel have limited SOS satellite connectivity; Samsung has announced forthcoming satellite capability in their phones as well. Somewhat klugey, these systems require manual alignment of the device; they operate on the GlobalStar network. Not all devices have this feature, and some are limited by the phone carriers. The geographic coverage is also quite limited. These should be considered back-ups until the technology becomes more mature.

What should you do to get ready for an emergency?

Select and install your chosen devices and set them up appropriately.

For EPIRBs and PLBs, that means registering them with the appropriate national authorities and mounting their storage brackets in suitable locations. Each device has a testing schedule and protocol, so add reminders to your calendar to ensure you keep up with the schedule. [Editor’s Note: It is also important to keep your registration information up to date, including the area in which you are currently sailing, details of any long passages you are making, lists of safety equipment and communication devices on your boat, and emergency contacts who are aware of your current sailing plans.]

For SEND devices, ensure you have the appropriate subscription in place, your emergency contacts are registered, and the appropriate Coast Guard and other safety contacts are in the device’s address book or contact list. If the device tethers with a smart phone or other device, ensure the appropriate software is installed and up to date, and that the tethering connection(s) have been tested. Having the tethering connection enabled on multiple devices adds redundancy. Most SENDs get firmware updates from the manufacturer, so find out how your device updates and schedule a check every 90 days or so to make sure that you are up to date. Ensure you have a charging/battery replacement protocol in place so that the device is always charged up or, if it has replaceable batteries, that you have spares on hand.

For DSC Alerts, make sure your radio(s) have your MMSI programmed in, that they have access to a reliable GPS signal, and that the radio(s) have a first-class antenna connection (testing with an SWR meter is the best way to ensure this).

Once the hardware and software are established, train your crew in the use of these devices and make sure they know how and when to use them. Preparing a ‘Cheat Sheet’ of simple instructions that can be posted in a handy spot ensures that crew are not falling back on memory in an emergency.

You have an emergency, what should you do?

If you are faced with a life-threatening situation or there is an imminent threat of danger such as loss of life or the vessel, potential for loss of life or the vessel, sinking, fire, loss of the rig, or other serious emergency, you should activate all of your emergency communications all at once. If you have all three, use the EPIRB, SEND and DSC alerts all at the same time.

• The EPIRB will get SAR resources mobilized rapidly on a nation-to-nation basis. It is, hands down, the most reliable distress signalling mechanism.
• The SEND will typically allow two-way communication on the nature of the emergency and what aid is required.
• The VHF DSC Alert will summon any nearby vessels to your aid.

If you are faced with a potential life-threatening situation or there is the potential for an imminent threat of danger to develop, you should initiate a two-way communication with a shoreside contact to seek advice and/or advise them of the situation (ideally with one of the emergency contacts for your EPIRB or SEND). This could be via any means available: Cell Phone, Starlink (email, teleconference, etc.), SEND, or whatever works. Nearby vessels should be alerted via a normal VHF radio call. This allows them to be aware of what’s going on and be ready to scale up response appropriately as the situation demands.

The two images in the article are in the public domain because they contain materials that originally came from the U.S. National Oceanic and Atmospheric Administration, taken or made as part of an employee’s official duties. From Wikipedia.