Quote Originally Posted by Whopper View Post
Not sure if it's related, but there was a large gray boat that was anchored between Kellys and South Bass most of the day. Never got close enough to see if there were diver flags or anything.
Well that was the area I was hearing that noise.. It was probably around 5 PM til 6. It would be a couple thumping sounds in succession. Very load and very weird, but under the surface for sure. My guess is some kind of sonar for looking for wrecks or for studying bottom beneath the lake bed.