There are some sweet side scan sonar systems that send out ~ 200khz chirps to give you a pretty good picture of the sea floor. It might make for a nice map of

There are some sweet side scan sonar systems that send out ~ 200khz chirps to give you a pretty good picture of the sea floor. It might make for a nice map of the bottom, but I think they are a bit pricey. https://www.google.com/search?q=side+scan+sonar+images&client=safari&hl=en-us&prmd=isnxv&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiqo8ml99LzAhWCAp0JHb9xANgQ_AUoAXoECAIQAQ&biw=428&bih=746&dpr=3 https://www.google.com/search?q=side+scan+sonar+images&clien... My depth sounder doesn’t like water that churned up with sand (e.g. prop wash + sandy bottom). Maybe the waves are kicking up sand around the break?