Adamsanta,
Thanks for posting all the pictures. My first thought in looking through them is turbulence but I would like to see a better view of the center section of your hull. Would it possible to take a picture looking up and forward from the transom? If you measured of the centerline to the outboard side of the hull to appears that the transducer is mounted pretty close to the half way point, can you confirm this? There are a couple things to know about how the Bottom Discrimination mode works on the 587. First there is a minimum depth and I want to say it is around 15-18ft. Second is that it uses both frequencies to determine the bottom classification even though only you are displaying only 50 or 200Khz. This means that both frequencies need to have good bottom returns for the BD mode to function. When you are looking for turbulence the things to key on are gaps in the bottom on 50Khz. Start at the dock to see how well the 50Khz is working and then gradually increase your speed. If you start to seeing noise, weaker returns or gaps that is signs of turbulence.
Snips