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Just returned to my boat after a two week hiatus. My new this season Garmin GMI 20 for some reason was displaying the same reading for both True and Apparent wind. My sense is that it was displaying only apparent wind. This was the case for both wind speed and direction. No previous issues
Tried calling Garmin when I got back to the mooring but they seemed to be having some major systems issues and were not answering any phone calls. Back home did some research and it seems that the wind vane used with the GMI 20 sends only apparent wind info. It then uses info from the GPS / Chartplotter (or a heading sensor) to calculate true wind. The manual for the GMI 20 indicates that there is a system setting for “Heading: sets the reference used in calculating heading information” Won’t be able to see if changing this setting corrects my issue until tomorrow.
Anyone familiar with the GMI 20 think I’m on the right track? Don’t know why this would all of a sudden become and issue or how a setting could change in its own. As these marine electronics become more complex it becomes more of a PITA to diagnose issues and even just figuring out how to configure the settings is a pain.
Found out I was on the wrong trail here. As it turns out I was assuming the transducer actually a triducer (speed, temp and depth) was all electronic when actually it still uses a paddle wheel. The real issue probably is a fouled paddle wheel not being able to send speed information used to compute true wind speed. Garmin sells the triducer on their website but it’s actually made by Airmar. Can’t tell from the Garmin website that it has a paddle wheel but found it out on the Airmar website. Garmins website provided no manuals for the triducer.
Did find out that the source of speed for purposes of calculating true wind speed can not be changed I either the Chartplotter or wind instrument menu.