Howdy from a year long or so lurker. All the great info here is awesome, particularly now that I have a question that hopefully someone can help me with. I recently replaced my separate GPS and Fishfinder units with a single unit, the components of which include a Garmin 3006c GPSmap/chartplotter, the corresponding GPS 17N antenna, a GSD 21 sonar module, and the corresponding transducer. Everything works great except the sonar/fishfinder. The first time out it worked fine up until I was cruising at about 14kts heading up Derickson Bay in what the chart indicated was 400'+ of water when the depth reading went to 24'. I slowed and eventually came to a complete stop to get an accurate reading but after that I could not. The next time the sonar seemed to work right was back in the small boat harbor at Whittier. Every time out since then I get good readings in the harbor until I exceed 7 kts or so, then it flashes with inaccurate readings. I expect that when moving along, but once upset the sonar will not read accurately even if at a crawl or stopped. I've tried turning off the motor, resetting all of the electronics, adjusting all of the settings, pretty much everything I can think of short of replacing parts. The Garmin tech line has been zero help so far. Anyone have similar issues? Any thoughts, ideas fixes would be much appreciated. BTW great weather in PWS last week, the shrimp were tasty too!