AIS for Boaters: Part 1

“When was the most scared you’ve ever been aboard a boat?” I get asked that question a lot, and every single time I remember a cold November evening in 1994 when a 40-knot gale frothed up the mouth of Chesapeake Bay during a boat delivery to Miami, FL.

This screenshot shows the plethora of information an AIS transponder can provide. Screen shot courtesy of
This screenshot shows the plethora of information an AIS transponder can provide. Screen shot courtesy of

But it wasn’t the weather that was so unmanageable; it was the confusing mass of barely visible ship traffic that raised my blood pressure. Today, that same evening would have been much less stressful, thanks to a technology called the Automatic Identification System, or AIS for short.

 This AIS transceiver not only broadcasts information about the vessel it’s installed on, but receives information about other AIS-equipped vessels as well. Note the various targets on the display, represented as circles with direction marks. Image courtesy of Furuno.
This AIS transceiver not only broadcasts information about the vessel it’s installed on, but receives information about other AIS-equipped vessels as well. Note the various targets on the display, represented as circles with direction marks. Image courtesy of Furuno.

Back in ancient times (20 years ago, electronically), a radar blip was about all you could depend on to locate other vessels at night or in inclement weather, such as fog. And even then, you didn’t know what type of vessel you were looking at. Determining its speed and course? Well, that required some serious, practiced radar skills. Today, with an AIS receiver—or even a smart phone, tablet, or PC with a 3G cellular connection—you can find out just about everything you need to know about shipping vessels around you and where they’re headed.

Here’s how the whole system works: In the simplest of terms, an AIS unit broadcasts a VHF radio signal from a ship or other vessel containing the following information: position, course, speed, vessel name, type of vessel, and radio call sign. This information can then be received by any other vessel or land-based station with an AIS receiver. Typically, that information is overlaid onto an electronic chart, map, or other electronic graphical representation so the user can see where they are in relation to the other vessels in the area. The data is networkable with many different marine electronics devices including radars, VHF radios, and chart plotters.

This AIS screen shot shows all of the AIS-equipped vessels in the New York Harbor area. That’s a lot of ships! Screenshot courtesy of
This AIS screen shot shows all of the AIS-equipped vessels in the New York Harbor area. That’s a lot of ships! Screenshot courtesy of

While ships larger than 300 gross tons have been required to be equipped with Class A AIS systems since 2002, there are currently no laws requiring AIS on most recreational vessels. It begs the question, “So, why should I think about AIS for my boat?” Considering the fact that a large ship traveling at speed can be on top of your boat within as little as 15 to 20 minutes from the time you see it in ideal (note I said, “ideal”) weather, I ask, “Why not?”

You’re probably interested in what devices are available to access AIS on your boat.  Carry on to Part 2 of the article.

VHF Radio Know-How Can Save Your Life

Modern VHF radios like this ICOM fixed-mount IC-M424 can do a lot with DSC and MMSI, but the most important function of a VHF is to broadcast a distress call on Channel 16 to other boats within antenna range.

Back in the day, a boat with a VHF radio on board had to have an FCC license, and anyone who used the radio was required to use the boat’s call sign in a radio transmission. I can still recite my call sign many years later, along with all the other numbers that get attached to a person and work their way into deep memory. There was a lot less idle chatter and bad protocol on the radio back then. (Might have been because there were a lot fewer boats, too.)

Today’s VHF radios are equipped with Digital Selective Calling (DSC) features that can send out a distress signal immediately, and report your position, too, as long as your radio is connected to your GPS or carries its own receiver. With a Marine Mobile Service Identity (MMSI) number, you can take advantage of some other DSC features, including making direct calls to another MMSI-equipped boat. Together, DCS and MMSI can take in and send out real boatloads of information automatically and instantly – again, as long as you’ve taken the time to hook things together, fill out all your information, and register your radio.

But despite all the modern conveniences, there are three things about marine VHF that haven’t changed, and these are the most important things to remember:

First, the system is line-of-sight, antenna-to-antenna. The height of your antenna, and the ones you’re trying to reach, make all the difference. (Luckily, the U.S. Coast Guard mount their antennae way, way up.)

Second, despite the new ability to make more or less private line-of-sight calls to other DSC/MMSI-equipped boats, the essence of VHF is that it’s a broadcast, meaning your voice is cast broadly — to anyone within antenna range who is monitoring Channel 16 (as anyone with a radio on board should be). And when you’re in trouble, this is exactly what you want — a good, big, old-fashioned broadcast.  Sure, you can use your cell phone to call SeaTow or BoatUS if you run out of gas or wrap your painter in your prop and can’t free it. Those aren’t (usually) true emergencies. But if you’re in serious trouble and lives are in immediate danger, you want to get on Channel 16 and send out a Mayday call to everyone within earshot. And the Rule of the Sea says that anyone and everyone who hears your call is duty-bound to respond. That’s comforting. And effective.

Which brings me to the third thing: Channel 16 is sacred. Do not gab on it. Do not ask for radio checks on it. If you use it to establish contact with another boat, switch immediately to a working channel. Better yet, just agree with your friends to use Channel 9 to get in touch. For radio checks, Sea Tow has established a great automated radio check service, so no one ever needs to call for a radio check on the distress channel (as if they ever did). In short, do not abuse Channel 16. The life you save by remembering that Channel 16 is sacred may be your own. Or mine. Thanks in advance.

For more detailed advice on how to do marine radio right, read VHF Radio Protocol by Peter d’Anjou and How to Use a VHF Radio by Lenny Rudow.

Doug Logan

VHF Radio Protocol

vhf radio
The average range of VHF radio is 20 miles.

The other day, while working my part-time launch-driver’s job, I got a call from a young child requesting a ride to shore from his family’s boat. The kid did a pretty good job on the radio, and I applaud parents teaching and supervising kids to use the radio correctly. After all, monitoring and talking on the Very High Frequency (VHF) radio channels is something every boater should know how to do.

Unlike my young caller, many adult pleasure boaters don’t know the protocols for using the radio. I say this as a professional mariner with more than a few sea miles under my belt. I also possess a Federal Communications Commission (FCC) Marine Radio Operators Permit and because monitoring and talking on the radio is part of my work routine, I can tell you there is a difference between using your cell phone and the very public high frequency radio—or at least there should be!

VHF Radio
Part 80 of the FCC Rules, plus those International Radio Regulations to which the US is a party, are the rules that govern radio use.

Because these same radio frequencies are used by commercial ships, and planes with licensed operators and call signs and monitored by USCG life saving authorities, the FCC has limitations on what and how things should be said.  Anyone can talk on the radio within these confines and pleasure boaters are not required to have an FCC permit to do so, but because this has to do primarily with safety there are certain fundamentals, i.e. protocols, that everyone must follow.

Here are some radio basics that all boaters should know:

  • Radio transmission should be in English.
  • The captain of the ship has ultimate control of the ship’s radio.
  • Distress traffic (grave and imminent danger requesting immediate assistance) in radiotelephony is expressed by speaking the word “Mayday” 3x at the beginning of the message, followed by the call sign and or name of the vessel. Then the particulars that would facilitate rescue such as position, length, color, and type of vessel, number of persons onboard, and nature of distress are given.
  • After Distress (see above), the next message priority is Urgent, which involves the safety of ship or person onboard. This is conveyed by speaking the word “Pan” 3x.
  •  Safety is the next message priority, which conveys a navigational or weather warning by speaking the word “Security” 3x.
  • These three are the only messages that are general broadcast. All others should be directed to a specific vessel or station.
  • Channel 16 (156.8 Mhz) should be monitored at all times. It is reserved for hailing and emergencies. Most radios have dual monitor switches that allow you to hear channel 16 and another channel at the same time. Commercial ships will monitor 16 and use channel 13 for hailing. You MUST switch to another channel for basic communications.
  • When attempting to contact other vessels on ch 16, limit calling to 30 seconds. If no answer is received, wait 2 minutes before calling again.
  • When you call another vessel, say the name three times and then ALWAYS identify your vessel. e.g., “BYC launch, BYC launch, BYC Launch, this is motor vessel Albacore channel 68, over.”
  • The word “over” lets the other party know we are done talking and it is their turn to talk. “Clear” ends a transmission without further response. “Wilco”says that the message is received and will be complied with.  “Roger” tells the other operator that all of a transmission has been received.
  • If you hear other people talking on your frequency, let them finish! Don’t talk over or “step on” other radio traffic, and always listen before transmitting.
  • Cursing and swearing is not allowed.
  • Make it short and sweet. Get to the point. Remember the safety nature of the medium. If you want to talk about how the fish are biting or how great the weather is, make sure you are on a “non-working frequency” (those routinely monitored by harbor masters or marinas for instance). Or better yet have these private conversations on your cell phone. Needless or superfluous radio communications are not authorized in maritime service. The primary purpose of bridge to bridge communications is for navigational communication.
  • Most cruising guides will provide the frequencies routinely monitored by harbor masters, marinas and yacht clubs.
  • Radio checks are a way of knowing your radio is sending and receiving properly. Again identify yourself, “radio test, radio test, radio test, M/V Albacore ch 68.” The proper response being, “M/V Albacore, loud and clear, (your location) Nantucket Harbor.” Better yet, use the new automated radio check system on ch. 28.
  • Sign off properly when your call is complete: “This is M/V Albacore going back to 16/13, off and clear.”
vhf handheld
Be careful with VHF handhelds not to lean on the transmit button and create an "open mike" situation.

For more information about VHF radio protocols, read the study questions and answers to the marine radio operators permit test, or simply understand the larger
FCC role in marine safety. VHF radios play an important part in safety at sea and should be used with respect and understanding of FCC and international treaty regulations.

This is Peter d’Anjou going back to channel 16, off and clear.