L.A. Meyer’s Bloody Jack series (of which I’ve read only the first five so far) is set in the Napoleonic era, and largely involves naval activities, but isn’t doing quite the same thing as Hornblower or Aubrey/Maturin.
For one thing, it’s a YA series; for another thing, the protagonist, Jacky Faber, is a girl, which means that there’s no way to write a traditional naval tale. What this means is that while some thing do happen on the HMS Whatever, an awful lot of it happens outside of the organized navy—on a whaling ship or a pirate ship or a Mississippi riverboat or even an on-land finishing school.
On the one hand, this gives the series a pleasant variety; on the other hand, it also makes it wildly uneven. The first book (very naval) is fun; the second (finishing school) is really depressing and frustrating; the next two (back on the sea in various ways) are back to being fun; and then the fifth one (journey down the Mississippi) was unlikable enough that I put the series down and haven’t gotten back to it.
There’s enough good in the series that I don’t disrecommend it, but if it’s Napoleonic fiction you want, there are a lot of really excellent choices, so “good enough, in spots” doesn’t put this one high on the list. Still and all, I might go back and read the rest of the series—there are another seven books—someday. And of course I should note that I’m not really the intended audience; if I were an actual YA, I might well have a more positive take.