Hey guys, ive done mainly fishing at sandbanks and stuff so have never really used a sounder that much. Went out on my cousins boat who he is also still learning to read sounders well. Ive attached some photos as i would like to get some help from people who actually know what to look for. I understand arches etc, and also not always u will get a perfect arch.
What you have there is fish under the transducer/boat. Because you are stationary the fish appear as straightish lines and not as aches. A fish needs to move through the sounder beam to produce an arch. You or the fish need to be moving. It would appear that the boat was moving up and down in the chop/waves to produce the shakey look to what is displayed on the screen. Hope this is of some help.