I have been trying for decades to find a book from my childhood. I would have been about 6 or 7 when I got it, so it would seem to be late 1970’s/early 1980’s. It was a hardcover book, about 8.5 x 11 size, with illustrations on each page that had the reader solve a mystery. I cannot remember the title though I seem to think it was a set of two, and perhaps the main character had “professor” in his name somehow. I also seem to recall one or both mysteries being set on a dock and/or boat. The illustrations were brightly colored with dark outlines; a graphic style more so than a detailed realistic illustration. Any help would be appreciated!