By Kevin

When you here the cliched warnings that GPS units sometimes fail so have a backup available, heed them.

In early November, we installed a new Garmin 441s electronic chartplotter, which we purchased at West Marine in Fort Lauderdale. We installed it by running the wires into the engine room (directly under the steering pedestal) and attaching the positive directly to the house battery bank switch and the ground to a ground terminal block that was also servicing our 12 volt auxiliary outlets.

Fail.

It seemed to work fine but when we got the boat off the dock in lightly choppy water, it cycled off. Each time we turned it back on, it would only stay on for 5 minutes or so. Fortunately, it was enough to get us to Miami and one of the crew had good local knowledge that allowed us to get into port after dark. (Thanks, Captain Gerry!)

West Marine was gracious and replaced the main GPS unit, in case the one we had was faulty. We kept the existing wiring in place and swapped out just that unit.

Fail.

The next time we went out, on a flat Biscayne Bay, it cycled off.

We rewired the positive to the 12 volt auxiliary circuit, as I suspected the house bank connection was loose.

Fail.

Unfortunately, the night we chose to leave for the Bahamas, crossing deep ocean water, it failed again. This time one of the crew (yes, Captain Gerry again!) had the Navionics iPad app and we used that for the 12 hour passage to North Bimini Island.

So, now in Bimini I hired a Garmin authorized installer to take a look. He thought the problem was the wimpy 3 amp inline fuse holder that comes with the unit. So, he replaced it with a heavy duty automotive-style fuse holder.

Fail.

We left the dock at North Bimini to sail 60 miles east. Within minutes of getting off the dock, the unit turned off again. So, we cancelled our crossing of the Great Bahama Bank and anchored out.

Since we want to get out of Bimini as soon as a weather window opens, we decided to order a new GPS chartplotter. We ordered a Garmin 78sc handheld chartplotter from West Marine. It will be shipped overnight to a private airplane company that flys between Bimini and Fort Lauderdale. Hopefully we’ll get it by Sunday, which is our next potential departure date.

So, the problem with the 441s should be either the voltage disappears, the voltage drops, or the amps drop. I turned on a voltage alarm on the unit when the problem first started that will sound if the voltage drops below 11.5. It hasn’t sounded when the unit cycles off. So, that leads me to believe either the amps cut out because of a corroded wire or the volts disappear because of a partially broken wire.  

The only 2 things left to do to troubleshoot are: Rewire the unit directly to the battery to see if it works without fuses, breakers, etc in the circuit; second, replace the power/data cable that came with the unit, as it may have an intermittent wire break that only acts up when there is some wave or wind movement.

But, that will have to wait until we get to Nassau.