Homicidal autopilots

I had a problem with my cellphone speaker magnet affecting the tiller pilot. It made my boat swing around and jibe when I sat next to it.

 

...I met a girl in a bar like that once....

 

gonzo....sort of like leaving a screwdriver next to the steering compass......hopefully you have learned your lesson now.....also watch where you install the fluxgate, and also use twisted wires (DC) anywhere near the compasses.

 

I totally forgot about the phone in my pocket. Never again.

 

Voltage fluctuation was the culprit in both of my autohelm nightmares. The first was on the first night of a delivery. Owner told us to please not mess with his plotter screens. Unfortunately, owner didn't sail at night and none were setup for that! So I'm on a strange boat at night with bad screens, and the captain is below finishing some work on the boat, and I'm three miles off Gun Cay under sail. I decide to start an engine. Then I go get some deck help with lights. Everything is fine until we are nearly on Gun Cay then the helm just dies. Turns out the compass was powered by the start battery and it went stupid when I started the diesel. The boat was balanced under sail and I didn't know the helm was dead for three miles. It wasn't until a week later, after two more incidents that I figured out what was going on. (but I began to fiddle with the screens immediatly!)
This could happen with the compass hooked to a house bank if a compresser started or a radio transmitter powered up. I wonder if a little DC/DC converter just for the compass might solve some of these problems?

 

DcDc converters to prevent voltage spikes are a good addtion to the " brain" circuit of an autopilot or any electronics..

 

6 Months ago I had an incident that put the use of autopilots and keeping the (power down switch within arms reach). One of the alternators on a 6LY2 malfunctioned and caused a magentic flux field that affected the Raymarine Fluxgate compass and resulted in the autopilot veering almost 90 degrees off coarse. At the time we were passing through and SPM (Single Point Mooring) field for oil tankers. As a general rule I would never leave the helm for longer than I can hold my breath; even if I am in daylight and have performed a clearing scan. .