During my formative years, I had access to many older publications and learned, or thought I did, that its' is the proper way to indicate possession. Thus:
"Speaking of this boat, its' hull needs patching up."
I am reading, mostly in current grammar blogs, that this form is absolutely incorrect. I am perplexed. For many years I have thought it was the opposite. I do not mind being wrong, so I thought I would ask.