I have a Garmin GPSmap 498, was included with the boat. My question, should I expect it to "keep" the bottom at 40mph? Wasn't sure if I purchased a better (read more expensive) finder, whether it would do a better job. It seems to loose the bottom after making a run to a reef just as I'm really interested in what the bottom looks like. It may take it several minutes to find it again. I keep the gain and most of the other settings on "Auto". Might be I just need a good tutorial on finders.
Thanks,
Tneut