If your slow drifting searching for larger targets you will find that different fish show up differently .HDS units seem to illustrate some what of a artists brush stoke at a really slow drift. So my advice after scratching my head around one for a year now is pay attention to the sounder when you hook fish and remember the different stokes the HDS unit portrays. At a slow troll speed the unit seems to display asmuch or less as most sounders on the market today. Don't be afraid to crank up the sensitivity to 90% at times and don't read into to much of the clutter , look for the stand out stokes as the blobs to me seem like , jellyfish and floating weed and rubbish in the water colum. Hope a fellow raider can post some info on the structure scan for the unit as now the Gen2 has a down scan capability of 95m ...Gen1 was 50m max.