How old is Jack & Maturin through the series?

I know there's some... Temporal freedoms taken in the series, and I'm perfectly fine with that. The ambiguity works well and hasn't bothered me in the least.

But, I am curious! They sometimes allude to Jack getting older, how he is capable of swarming up the... Ratlins? Ratlines? (Help, I've only done the audiobook versions!) "despite his age".

So, how old is he? I did find links to some articles discussing this, but they were all 404 by now, as the discussion on this sub was 11 years ago. I figured a new discussion could be interesting, even if I could probably "just google it" :)