Just when you need it the most

[Shippy]

Last Friday, we were out on the bay when a thunderstorm came running down the river. We decided to ride it out figuring it was only going to last 15 mins or so. The storm wasn't that big of an issue, however for the first time, my Autohelm Tri-data started going on the fritz. It was jumping all over the place, but most of the time was showing 0 depth and 0 knots. Intermittedly it would jump back up to a more reasonable, yet not accurate reading. Fortunately we had the GPS so we knew exactly where we were and knew we were in enough water. Anyone have any idea what may have cuased the tri-data to go wacko? It was at the start of the storm before any heavy rains or wind and the seas weren't choppy at all????Thanks...

 

[Bill O'Donovan]

Makes no sense

Unless (1) the battery connections got loose, or (2) you were in the Twilight Zone. In the future, I'd head in the moment you see a thunderstorm approaching. I've run 100 trips a year for 5 years and just had my speedometer go dead. Turns out it was seaweed stuck in the impeller.

 

[Claude L.-Auger]

Air charged up with electricity?

I had a similar experience with my former boat ST-50 Tri-data. We were sailing at hull speed, with the occasional planing down a wave. Thrilling and we were all watching the knot meter as it climbed over 8, then over 10, topping out at 14.3! Even though we had smiles to last us days, sailing a 28.5, all of us knew that something had happened to the Autohelm to make it read that high. We figured that with lighning and thunder all around us, there was so much electricity in the air to create a disturbance in the instruments. The tri-data worked fine after that incident, as if nothing had ever happened. Wonder if somebody has an explanation? BTW, we were heading in to eventually seek cover. Regards.

 

[Gord May]

Atmospheric Electricity

Claude probably came as close (to explaining) the odd event as you'll get.A Grounded Farraday Cage (Aluminum Instrument 'Pod') might help.Gord

 

[Shippy]

That was my best guess also

When we spotted the front, it was coming from the direction of our port, so heading in really wasn't the best option considering that heading home would take us up a narrow channel that also has working tugs and barges. So seeking other shelter such as a protected cove was my first thought, howver when the tri-data went haywire, I didn't feel comfortable nosing into a cove with no real sense of water depth. About half way thru the storm, everything started to work properly again. I think the electricity in the air could be the issue, however that stinks because that is when you depend on the instruments the most.