Novel review: Herman Melville - Moby-Dick (1851)

Maybe my first foray into the classic literature canon but I'll try to be indulgent despite judging it by its story crafting/telling and not its poetic value. I bought this Penguin Classics edition in a thrift store half a year ago and finished it today after a month or two of uneven reading.
My first reaction is that the hype is mostly deserved but the major faults given a pass by literary people who don't want to treat it as a novel; which it is supposed to be.
Ahab's mania is beautiful and pure, even in his rare showing of weakness or sorrow, that much is true. The various characters expanded upon aren't boring or flat, yes. The overdetailed description of whaling (the business, technique, the crew's valour) is entertaining and finally that slow descent into madness towards a fitting end does deserve the too-often misused word "epic".
Add to that Melville's obvious writing talent and you've got a masterpiece.
…Sadly, stopping here would be ignoring some glaring issues. The first would be that said writing, while good, often crosses my "purple prose line" - or more accurately rams it - with self-indulgent segments full of philology or religious references and unlikely character theatrics that made me roll my eyes more than once.
I mean, an entire chapter of ~10 pages analyzing the white colour of Moby-Dick really isn't a good idea. And this kind of rhythm-trouncing antics becomes more and more frequent as one progresses through the work, until it peaks at something like 2/3 then abates a bit.
Moby-Dick simply is hamstrung by Melville not wanting to choose between novel and poetic prose then proceeding to ruin the whole by sitting firmly in the middle without exercising much restraint.
Drastically trim and reduce those encyclopedic chapters, same with the jarring theatrical outbursts and fits of academic references and maybe focus a bit more on the story telling or characters. Then I guarantee you'll have something that reads smoother than swallowing a bucket of rusty nails.
Basically, there's a truly good novel struggling to get out of that (at times brilliant yet often boring) mess but that is not what I got to read.