Can the first person singular pronoun 'I' take in 's' in the simple present?

I am quoting from The Memoirs of Sherlock Holmes, The Gloria Scott by Arhur Conan Doyle : "Thank you sir, said, the seaman, touching his forelock. I am just off a two-yearer in an eight-knot tramp, short-handed at that, and I WANTS a rest".
Is it just a spelling mistake (I am using a book from Wordsworth classics) or ‘I’ does take an ‘s’ in some situations ?