That was such a hard slog. We can probably cut ol' Jules Verne some slack given he helped start the genre but holy crap that was quite tedious.
So, first off, I don't think there is one single woman in the book (there are crowds of people on a boat but there's no single defined character that is a woman.) The Nautilus is full of apparently celibate or gay men as they never touch land and there never seems to be any women about.
So what happens: well, they sail around, the main character describes sea creatures, they often hunt and harpoon things, and generally chat. They have an improbable stabby-harpoony battle with a bunch of octopi. Kill a shark, a bunch of sperm whales (there's some really odd scientific name that I googled came up with sperm whales), a dugong, some kangaroos, countless fish, some birds, turtles, whatever they come across (but not some other whales for some incomprehnsible reason).
But occasionally, for paragraphs and pages the main character just goes on a tangent speaking in mostly scientific names of things in the ocean. It's like Jules Verne got a book of sea creatures for his birthday and then replicated whole passages in the book. It was a bit dull and my eyes did glaze over.
I found in the meshes of the net several species of alcyonarians, echini, hammers, spurs, dials, cerites, and hyalleae. The flora was represented by beautiful floating seaweeds, laminariae, and macrocytes, impregnated with the mucilage that transfused through their pores; and among which I gathered an admirable Nemastoma Geliniarois, that was classed among the natural curiosities of the museum. P. 124.
And the main character, a naturalist, must be a pretty crap one as he thinks that 'the unicorn' (what turns out to be the Nautilus) is an electric narwhal. What.
The only thought I had as I was reading it was how improbable it was, but that improbability of not knowing what the ocean contains (or what the South Pole is made of) is today's equivalent of going to Mars or other planets. So there's the grand tradition of making shit up and looking a bit daft later on in science fiction.
I think part of the problem with the plot is that if you've got an invincible submarine and you're not going to restrict the movements of the people you've taken aboard - there's not a whole lot of dramatic tension. The last 10 pages or so were the best as there was some actual tension, rather than just: 'Oh! we'll do this. Oh we can't. Boo.'
Finally, one of the main characters was named Ned Land and he was supposed to be from Quebec. Not a very french name which bothered me throughout the whole book! Also this line: "Who calls himself Canadian, calls himself French." I don't think so Mr. Verne.
But really, I don't recommend reading it unless you really like fish and pointlessness for 317 pages. Or oysters, I think there was 3 whole pages talking about oysters. It was hard going for not really much reward. Basically, you could read the first 50 pages, then skip to the last 50 pages and you'd be sorted. Maybe not even that many. 2/5 stars because it's old or whatever.