An Alarming Situation

Cruising boats have a lot of safety systems.  Many of these systems are equipped with audible alarms to alert the crew to potential problems.  On Fulmar, we have alarms for engine overheating, low engine oil pressure, low alternator voltage output, low battery voltage, shallow water depth, radar target proximity, Automatic Identification System (AIS - an anti-collision system), and anchor dragging (which tells you that your boat is moving when it shouldn’t be).  Both of our marine radios also have alarms that will sound if another nearby vessel is having an emergency.   We even have an alarm to alert us if the refrigerator temperature gets too warm.  Yes, warm beer is an emergency!  

Smoke and carbon monoxide (CO) alarm.

Then there are the really scary alarms: carbon monoxde, smoke, and propane gas leak.  Carbon monoxide (CO) can be a problem if there is an engine exhaust leak or if the cabin is sealed up tight while you’re roasting the Thanksgiving turkey.  Propane is used for cooking on most cruising boats and because it is denser than air, any propane that leaks from the system will sink to the lowest point and can fill the bilges, causing a devastating explosion.  (Go ahead, Google “boat propane explosion”.  It will sober you right up.)  And it may seem nonsensical, but most sailors are far more afraid of fire than they are of storms or rough seas.  Most pleasure boats are made of fiberglass and no other construction material burns faster or hotter than fiberglass.  Throw in the other flammable materials that you typically find on cruising boats, like 50 gallons of diesel fuel; 20 pounds of propane; 5 gallons of gasoline; and a few gallons of solvents, paints, varnishes, and lubricants…well, you get the picture.

The control panel with status indicator lights for Fulmar's two propane "sniffers."  Sensor I is located near the tank, below the air-tight propane locker and sensor II is beneath the galley stove.

All of the alarm systems on a boat are meant to warn the crew before a situation becomes critical.  The problem is that they all sound pretty much the same: high-pitched, ear-piercing pulses.  BEEP BEEP BEEP!  When an alarm sounds, it can take a little while to figure out which one it is.  We try to remember what each one sounds like, but it’s a challenge.  We also know where each alarm is physically located.  Manufacturers intentionally make the alarm sounds very high-pitched because high frequencies are easy to distinguish from the other sounds on the boat (despite what most people think, a sailboat can be quite noisy).  But the problem is that the human auditory system has trouble localizing high-pitched sounds, especially ones that are brief.  In other words, it’s difficult to tell where the alarm is coming from.  You may have experienced this when one of your home smoke alarms started to “chirp” its low-battery warning at 2:00 AM.  You groggily walked from room-to-room desperately trying to figure out which smoke detector was dying.  

To help identify an alarm sounding on Fulmar, each one has an indicator light on an instrument panel and the engine alarms also have gauges.  When an alarm sounds, you first check the most likely ones.  If the engine is running, you check for overheating, low oil pressure, or low alternator voltage.  If it’s none of them, you check the smoke, CO, and propane alarms.  Context helps.  If you’re not running your engine or cooking, it’s probably not any of your engine alarms or the CO alarm. 

Fulmar's engine instrument panel.  When the oil pressure, overheat, or alternator voltage alarm sounds, one of the red indicators will light up to tell you which alarm is sounding.

With all of these sensors, it is pretty common to hear an alarm.  Sometimes the settings are too sensitive or an alarm may be malfunctioning.  When we installed our new AIS, the default setting triggered the alarm whenever another vessel broadcasting an AIS signal came within a mile of us or when a collision could occur within 5 minutes.  These default settings are appropriate for sailing far offshore, but way too sensitive for near-coastal sailing, where there is a lot of boat traffic.  In the Intracoastal Waterway, this AIS alarm was sounding every time we passed another boat, which could be every few minutes.  It was very annoying and it really upset the overly-anxious canine member of the crew.  Loki retreated to the foredeck or the v-berth to get as far away from the alarm as possible.  We quickly figured out how to disable that AIS alarm, much to Loki’s relief.  

All this is background to the story that we really want to tell…     

Last month, we were sailing across Albemarle Sound during some pretty “sporty” weather conditions, when all of a sudden we heard  BEEP BEEP BEEP!  It was the CO/Smoke alarm.  We were able to identify it immediately and also determined that it wasn’t telling us that we had a fire or CO leak; it was telling us that it was malfunctioning.  Probably the internal battery was dying, even though it was supposed to have another 2 years of life.  In the heat of the moment, Janet removed it from its mount and stuck it in a sock drawer to keep it from driving us (and Loki) crazy.  The next day, we bought a replacement and installed it.  But we didn’t throw out the old one because it is considered hazardous waste and we didn’t know where to properly dispose of it in an unfamiliar port.  So we left it in the chart table and forgot about it.  

A few weeks later, we were in Chesapeake Bay heading for Deltaville, VA when again we heard  BEEP BEEP BEEP!  This time we couldn’t figure out which alarm it was.  None of the indicator lights or engine gauges showed anything out of the ordinary and there was no smell of smoke or gas.  It was an unfamiliar sound and we couldn’t tell where it was coming from.  It would give a few ear-piercing beeps then fall silent before we could locate it.  Janet would go below to investigate but the alarm would stop.  She’d go back topsides and a few minutes later it would sound again.  BEEP BEEP BEEP!  It was driving us crazy, especially the poor dog.

Then we remembered that we still had the old smoke/CO detector in the chart table.  It sounded different but we attributed that to the fact that it was inside the chart table and to its dying battery.  By that time we were entering a marina so we were too preoccupied to deal with it.  But the alarms were becoming increasingly frequent.  BEEP BEEP BEEP!  There was no doubt we had arrived; the entire marina could hear us coming!  When we were safely tied up to the dock, we figured out how to completely disable the hard-wired battery and disposed of it at the local boat yard.  Phew, what a relief!  

The back of the old smoke/CO alarm, showing how you can permanently disable the battery.

The next day, we were headed to Urbanna, VA, and were more than a little surprised when that same alarm sounded as we passed under the Rappahannock River Bridge.  BEEP BEEP BEEP!  What the heck?  Now we were getting really worried.  If it wasn’t the old smoke alarm, it must be a real alarm and we must be in some kind of danger.  But what?  We still couldn’t figure out which alarm it was or the location from which it was coming.  Damon ran below while Janet negotiated a tricky spot – passing under the Rappahannock Bridge while dodging a tug and barge.  

The high temperature alarm for our refrigerator with its fuse removed to disable it.  We were trying to identify the mystery alarm through a process of elimination. 

We checked all of the alarms and looked for anything that seemed out of the ordinary.  The engine seemed to be running fine.  The bilge was dry.  It wasn’t the new smoke/CO detector (we physically removed it from the cabin and brought it topsides, where it happily and quietly rode along silently in the sunshine).  It wasn’t the propane sniffer.  But this mystery alarm kept sounding every 15 minutes or so.  BEEP BEEP BEEP!  BEEP BEEP BEEP!  What in the world?!  We reduced engine RPMs and slowly made our way to Urbanna, worried there was something terrible happening on the boat.  Loki retreated to the bow, glaring back at us with disgust.  

Poor Loki hiding in the v-berth.

Our relief at reaching the snug harbor at Urbanna was shattered as the alarm screamed relentlessly as we turned into the channel.  BEEP BEEP BEEP BEEP BEEP BEEP BEEP!  The sound appeared to echo, as if it was coming from inside a large compartment with lots of hard surfaces.  The most likely spot seemed to be the engine room.  The trouble is, there aren’t any alarms that are located in the engine room, at least none that we knew of.  Maybe Fulmar’s previous owners had installed some sort of alarm down there that we didn’t know about.  We limped to the anchorage and were relieved when we had the boat anchored and engine shut down.  Blissful silence – no engine, no alarm.  Phew.  Now to figure out what was happening.

We tore the boat apart looking for this mystery alarm and couldn’t find anything.  We like to think that we know our boat’s systems pretty well; it was a little embarrassing to have an alarm that we couldn’t identify.  So Janet turned to her people, the Women Who Sail FaceBook group.  She posted a question to solicit ideas from the group’s members.  They came up with a lot of good suggestions (without any snarky comments about not knowing our boat well enough to find a simple alarm, which is what you often get from other sailing forums).  We were still stumped until one of the group members asked if we had recently purchased a new iPad or updated our navigation software.  In fact, a couple of weeks earlier, when we were in Coinjock, NC, we bought a new Android tablet to replace our aging and unreliable one.  We use the tablet as a backup to our boat’s main navigation system.  It is always helpful to have redundancy on a boat.  We loaded the latest versions of Aquamaps and Navionics on it.  We tend to use Aquamaps in the ICW but since we have been in Chesapeake Bay, we switched to mostly using Navionics.  

A chart displayed by Navionics on our new tablet.  Our boat is the red arrow pointing upwards in the center of the screen.  The smaller red arrows are other boats that are underway.  You can see one off our starboard bow, heading away from us and one approaching from around the corner at the bottom of the screen.  These two boats are broadcasting AIS data which includes their identity, type of vessel, size, position, speed, and heading.  Our AIS takes this information, along with that on the motion of our own boat, and calculates the closest point of approach and the time to the closest point of approach.   

When we started using Navionics, we were surprised to find that it displayed AIS data (it shows the locations and headings of other boats on the chart plotter).  Our previous tablet didn’t have that capability.  We realized that the new tablet was somehow getting the AIS information from the boat’s main navigation system.  We didn’t think much of it at the time, but the commenter in the Women Who Sail forum said that she had experienced the same thing when she replaced her tablet and that it was the AIS alarm in the new Navionics.  It turned out that the tablet had automatically connected to the wifi hub on the boat’s main AIS system (Vesper AIS) without our knowledge.  We tested the alarm and BEEP BEEP BEEP!  It was unmistakably the same alarm.  The sound quality of the alarm made it seem like it was in an echo chamber, hence the reason we thought it was coming from down in the engine room.  We didn’t think of an AIS alarm because we already disabled the main AIS alarm.  The default alarm settings in Navionics triggered it whenever another boat came within a half mile.  We realized that every time the alarm sounded, we had Navionics running and there was another boat near us.  If we had used Navionics in the ICW or while transiting through Hampton Roads, one of the busiest ports in the country, we probably would have figured it out immediately.  

Mystery solved…much to Loki’s relief.  And thankfully, it wasn’t a problem that we had to fix, other than to disable the alarm.