If you're looking to read a story of surviving at sea, read Unbroken. Alone : Orphaned on the Ocean is not very well written, twice as long of a book as it needs to be (the author wants to remind us about the toughness of Wisconsonites every few pages), and, oddly, kind of boring.
The true story of Tere Duperrault's ocean survival after her family is murdered on a sailing yacht was news to me. The background on their killer was sad, and I am glad to know more about this history. There really is very little focus on her time on the float (which was disappointing as that had been the reason I was compelled to read this book). I can see how it was therapeutic for Duperrault to co-author this book, but a newspaper article on the story would have been enough for me.