I swear to you that just the other day I was trying to find these books, but I couldn't remember the names of the characters or anything other than there was a

I swear to you that just the other day I was trying to find these books, but I couldn't remember the names of the characters or anything other than there was a group of young boys in a club doing some shenanigans on a lake. I was, of course, looking for "The Strange Sea Monster of Strawberry Lake (1960)". Thank you, thank you, thank you for posting this here! EDIT: I also remembered the Old Cannon one. Awesome stuff. I'm going to re-read them!