I had Moby Dick assigned in a high school English class and never made it past the first chapter or two. I’m reading it now as an adult (I’m about 80% of the way through) and I’m enjoying it immensely.
I agree with you that the conventional plot, the part we all know about the tyrranical captain with the whalebone leg, is hardly found in the actual novel. The part I’m enjoying is the interior life of Ishmael. He is a lowly deckhand on a whaleboat, about the lowest level of 19th century society and yet he is an amazingly erudite, highly educated person.
The best description I have of the story is that it is essentially the autobiography of Dilbert’s genius trash collector. Would you expect that book to be a riveting tale of getting up early and hanging off the back of the truck?