Pretty good!
I recently went up to Madeline Island and bought three books related to the general Lake Superior area in one way or another. The first one I read was marginal. The second one I read was quite bad. After two strikes, I began, with trepidation, the Unholy Apostles: Shipwreck Tales of the Apostle Islands, which I bought at the Bayfield Maritime Museum ... and it was quite good!
With numerous clippings and quotations from ye olde newspapers and crew member accounts, the author gives relatively short chapters, each covering a notable shipwreck from the heyday of the shipping era on Lake Superior (Part 1 being pre-1900 wrecks and Part 2 being post 1900 wrecks - but don't expect the Edmund Fitzgerald story as it isn't in here). Each chapter begins with the vessel's specs, which can be (let's face it) quite boring for the layperson (I was reading aloud to a friend for whom English is a second language and I broke up into laughter while reading out the long litany of maritime jargon, and said, "This must be the most boring thing for you." He said, "Actually I don't understand anything you said"). Still, Keller manages to make the actual accounts of the ships interesting. The loss of life is appalling, but there are also accounts of lives saved! Especially compelling is the story of the SEVONA, and be sure to read the account of the R.G. STEWART all the way to the end!
One drawback of the book is that, like many books that are published independently, the actual printing is not sharp, and photos lack proper contrast to see well, as if they were copies of a copy (they may have been, who knows). Also, while the book is edited well without any considerable typos, I really think using a few commas could help readability for some sentences -- enough so for me to notice (maybe the comma key was broken the day they typed it).
Overall, GOOD!
Spoiler: The ship sinks.
My two cents: Christening a ship as "Coffinberry" was just asking for trouble, come on.