I missed this post when it hit so I’m catching up.
John thank you for the Buck quote and posting the info, great stuff!!! A miracle of science that water density works this way.
Love the article on how we all have our own interpretations. This is why a lot of my best learning has come from being in the boat with other spoonpluggers.
So, for me, I take 1 to 2 minutes when I launch and drive in the straightest line possible from shallow to deep and I find out these things: inside weedline, outside weedline, other various mental notes on the weeds like width and density, all breaklines - where and how deep they break (not always but usually the same around the lake and when you find place that are different you will notice them due to the first 2 minutes of study), hard to soft bottom transition, and finally thermocline. All of these things show up perfectly clear on any depth finder. Present day I find them easiest on downscan view.
Finally, for me, the thermocline is just as valuable as the rest for a few reasons. First, in most lakes I fish I will never catch a fish below it. Some have argued this point with me as there are some lakes heavily spring fed and/or have oxygen below the thermocline but this is rare. I’m not a scientist and I know thermocline is a sensitive subject here but for me it is a significant breakline in the lake and it changes depths and strength until it disappears in the fall. And yes, some lakes don’t get one but this also seems rare. Other lakes can lose it for various reasons but it can also come back.
One last thing for anyone new and/or struggles with remembering the things I listed in my first 2 minutes on the water - write them down. Keep a notebook in the boat with a clipboard and draw out your side view from shallow to deep. You will always find one in my boat. One of my favorite aspects of spoonplugging is the knowledge to identify these things and study them, learn from them, and catch fish because of them. Pretty cool.