False Alarm
MANY EGO-BRUISING LESSONS WERE LEARNED ON THE DAY I INADVERTENTLY SET OFF A MAN OVERBOARD ALERT.
There are ego-bruising lessons to be learned when you set off an MOB alert by mistake.
Due to an obscure but noteworthy electrical glitch, plus oodles of distracted seamanship on my part, a sizable U.S. Coast Guard team spent part of a beautiful Saturday looking for an AIS man overboard alert associated with my boat,
Gizmo. Fireman Joey Jansen-Hedrick and Petty Officer 1st Class T.J. Iaci were the guys in the boarding party; they had to deal with an owner/ operator (me) who was pretty sure they didn’t know what they were talking about. But they were politely persistent. And as it turns out, they were right.
It was July 29 and I had begun the day at about 10 a.m., motoring over to the launch ramp dock at Eaton Point in Camden, Maine, to pick up six guests. We then tagged along behind the classic boat parade and back into the inner harbor, where we took a few gawker turns around the amazing superyacht
Le Grand Bleu anchored north of town. Then we crossed the bay to check out seals and such, and timed our return to watch the noon Camden Classics Cup race starts. We even took pictures for the
PenBay Pilot. It was (almost) a complete blast of a summer Saturday excursion. I know this is an accurate overview of our cruise because it was recorded on the NMEA 2000 log of received AIS tracks collected by a Yacht Devices YDVR, and later displayed as a GPX file in Coastal Explorer.
Unfortunately, I didn’t have a clue about the one event I really should have paid attention to. I learned about it as I headed back to the ramp to drop off my guests. That’s when USCG 47228 from Rockland Station vectored in on Gizmo. Over VHF the boat’s team told me they needed to board in order to search for the source of a mysterious DSC man overboard alert. While I picked up a mooring, they (nicely) got an assistant harbormaster to ferry over the petty officer and fireman in a small boat.
As I expected, the MMSI they were looking for did not match Gizmo’s FCC-issued vessel MMSI, which was programmed into an Icom M605 that had been powered up throughout the trip and a Standard Horizon HX851 handheld. They wanted to check the handheld, even though it had not been touched. It was at this time—as Officer Iaci patiently asked me if there could be other radios aboard (there were), and I appealed to him to allow me to get on my way—that I wondered if the problem was really a DSC MOB distress call, which requires several manual steps, according to the M605’s manual. “Maybe you mean an AIS MOB distress message?” I asked. “Geez, I’ve got four of those on board.” I headed forward to grab the ditch bag I’d recently used to organize the various safety devices that I was testing. I certainly did not expect any of the beacons to be activated, but when I pulled the McMurdo FastFind S10 out of that big EPIRB pocket, its white translucent end was flashing. It was obviously on. I found instructions on how to turn it off and that’s when the Coasties started grinning.
Iaci and Jansen-Hedrick got the satisfaction of seeing the S10’s preprogrammed MMSI match up with the one they were looking for. Mission accomplished. I, too, was happy to head back to my mooring, though that’s where my embarrassment was compounded as I learned the USCG had tried to contact me by cell phone and even Facebook. I had some explaining to do, at least to myself.
How could a boat as elaborately equipped as Gizmo not see an active AIS MOB alert that was nearby? And how did I miss the USCG calls on VHF, cell phone and Facebook? But most pressing was the mystery of the S10: How the hell did the well-stowed and untouched unit turn itself on?
The S10 has a hand-grenade-like, pull-to-arm pin; the feature is appropriate for an AIS beacon designed for divers who might get separated from their mother vessel. You can activate it while wearing heavy gloves, even mitts, but not accidentally. The spring-loaded orange top easily twists 90 degrees counterclockwise when you want to turn the device off (or test it), but it won’t budge clockwise to “on” unless the pin is pulled. And I had never pulled it.
I was planning to write a WTF email to McMurdo until I mentally connected a few dots—specifically, the magnet symbol molded onto the orange top (a magnetic switch), and the location of the ditch bag.
A couple of weeks before, I had stuffed the ditch bag into a forward starboard hanging locker, with the EPIRB pocket up close to those high-current bow thruster and windlass cables, as well as the 100-amp circuit breaker. In retrospect, I vaguely knew that electromagnetism was possible around such serious 12-volt power flow, but could there have been enough of a focused magnetic field to activate the S10?
There’s an app for that. Actually, there are umpteen magnetometer apps, since most smartphones have the necessary sensors. I quickly settled on the Physics Toolbox Sensor Suite. (I liked it so much I purchased the $2.99 pro version.) Yes, this is the part of the story where I rediscover the joys of joyful modern technology. Even the free version of the Toolbox app let me accurately measure a total magnetic field with its three vector components and collect the results to a .csv file I saved to the GDrive cloud. Later, I converted the data to graphs on a PC.
I held the top of the phone an inch or so from the magnetic area of the McMurdo to determine the approximate magnetic force required to turn the S10 on if the pin is pulled and the orange top is turned 90 degrees clockwise.
Now here’s what happened magnetically when I put the phone in the ditch bag, returned it back to the locker and then ran the thruster and windlass intermittently. There was a relatively significant magnetic burst—about 2.5 times what I measured from the S10’s magnet. I had used the thruster briefly during the cruise to get off the ramp dock, but that timing did not jibe with what I learned from the USCG command center at Sector Northern New England in South Portland.
It was Petty Officer Nicole Van Gieson, an operations specialist in the command center, who had called and attempted to contact me via Facebook, which was not easy since an AIS MOB beacon is not registered to a boat or a person. I figured that the command center saw the beacon tracking with Gizmo on their AIS monitoring screen, but it was more complicated than that. They got their first report of an MOB alert from another vessel just before noon, with an alert position out by Lasell Island. Gizmo was approximately there, according to the USCG AIS screen, but it took another report or two for the USCG to gain confidence that this was an unusual MOB, apparently swimming across the bay at 5 to 10 knots alongside a Duffy 37. It was linked to me via its AIS MMSI registration, some of which is public.
Van Gieson explained that the USCG always acts on the worst possible scenario. (“We strive to have a Coast Guard asset en route within fifteen minutes of a distress call,” she said.) But they also try hard to contact boaters who could be in distress, to double-check. “You would be amazed at the number of people we have been able to locate safely using Facebook,” she later wrote to me... through Facebook. In fact, she’d been reading Panbo when I called on Saturday afternoon, and was perhaps aware that I might be a guy with too many gadgets, even if she just seemed glad that the incident was resolved.
I’ve heard a lot about this admirable USCG philosophy. Of course, they’d like to reduce the huge number of false alarms, and they’re rightfully fierce about intentional ones, but they don’t presume bad intentions and they want boaters to contact them, even if they’re not sure their situation has reached distress level. This is why two-way distress messaging has great value.
At any rate, knowing that my AIS MOB false alert was called in, not
actually seen on AIS at the command center, helps explain the DSC/ AIS mix-up. But I will note that the USCG, and yours truly, could have realized that an MMSI starting with “972” had to be an AIS MOB beacon, as explained at the Coast Guard’s NavCen and often written about on Panbo.com.
But, wait, if the thruster turned on the S10, why was the first report almost two hours later? My theory: The beacon was only intermittently getting sufficient GPS info in and/or AIS signals out, because it was upside down relative to its desired antenna orientation, which is plainly marked on the casing. Plus, it was stuffed in that locker with lots of possible signal obstructions.
Then I remembered the YDVR log, which led to theory refinement and confirmation. The recorder is on the boat’s secondary N2K network, and it not only captured Gizmo’s own AIS track as it was received by the Icom M605, but also the boat’s high-resolution GPS track and the AIS track of the S10 beacon. That 972 MMSI track started just after I left the ramp dock shortly before 10 a.m.—thruster activation confirmed—and ended at the USCG rendezvous.
But the 972 track is also quite consistent over those three hours, indicating that the S10 did have a GPS lock and was transmitting regularly despite its location. I do think that the transmissions were quite muffled—otherwise other boats and the USCG would have been on the case sooner—but the S10 performed pretty darn well in this unplanned test.
McMurdo, incidentally, had never before heard of an accidental magnetic activation of an S10 in its protective pouch, but they were quite interested in this incident and even enthusiastic about its educational aspect. In fact, after looking over my findings, they wrote: “As a result of your detailed analysis of this magnetic field false activation, McMurdo will update our product catalogue to ensure our customers are fully aware of storage and handling best practices.”
So, maybe I can count that as an unintended mission accomplished, except that I still haven’t come clean about my failure to see that the S10 was active. After all, the prime function of an AIS MOB beacon is to alert the boat that it’s on before activation, and freaky Gizmo had two AIS receivers and many AIS plotters turned on that day. Plus, as McMurdo justifiably pointed out, one benefit of its new G8 EPIRB with AIS locator is that it could quickly help a boater deal with an accidental activation.
Part one of my answer is easy. Sometimes the always-on Vesper XB8000 AIS transponder does not join Gizmo's main N2K network when it's turned on. I think the behavior is fairly peculiar to this network, and on the day of that cruise, I imme-diately noticed the lack of targets on the three flybridge MFDs it feeds. But, I didn't bother to go below and reboot the XB. I could see all the boats fine, anyway, and there was lots of enjoy-able socializing going on.
Part two of my answer makes me cringe. It was beautiful that day; we were cruising in very fa-miliar waters, and there were friends on board, which caused me to become distracted. In retro-spect, I'm quite sure that I did get an AIS MOB alert, a very loud one, but I shut it down without looking at what it was.
At the time, I was still getting acquainted with Vesper’s brilliant new smartAIS transponder and its alarm. So, when a loud siren went off shortly after I thrusted Gizmo off the ramp dock, my first guess was the Maretron ALM100s, the only alarm system I’ve encouraged on this potentially way-over-alarmed vessel (that is, until the compelling Vesper update). But there was no sign of alarm on the Maretron displays, and it kept wailing away even when I briefly switched off the N2K network. And, mind you, I was maneuvering through a large field of moored yachts from the lower helm with its diminished visibility while six fresh crew were getting settled or looking over my shoulder for the source of the annoyance.
Finally, I remembered the new Vesper features and had to scramble to open the WatchMate app on the iPad (because I had not yet installed the physical switch). I presumed it was either an AIS or an anchor drag alarm—both of which I had recently fooled with—and went right to the app page where I could mute the siren. But the Vesper XB8000 can also alarm on an AIS MOB message, again even with the app unopened, and I believe I proved that it is almost foolproof.
So many lessons were learned. Hopefully, a lot are already obvious, but I should tell you about a few more mistakes that were made. I should have had another VHF on channel 16 on the flybridge, since I often had the Icom CommandMic on the channel used by the parade and race organizers. I should have had more than a draft of a checklist to consult prior to getting underway; it should have had items like reboot the Vesper (until that glitch is solved). And I should have remembered that the high amount of accidents occurring close to home is a real thing.
Finally, I’d like to apologize to the boaters out on Penobscot Bay that day, whose beautiful afternoon was interrupted by a mysterious and unnecessary AIS MOB alert, and to the USCG, which did an exceptional job of handling the incident and yours truly. I believe that the fabulous safety devices we have these days, and the outstanding SAR services they often alert, come with a responsibility to use them properly, including awareness that they are being used.
Hopefully, this deep analysis of what went wrong will be useful to my fellow boaters. As the wags at Despair, Inc. note, “It could be that the purpose of your life is only to serve as a warning to others.” For more information on this incident, as originally written by Ben Ellison, visit Power & Motoryacht- sponsored Panbo.com.