The Sea Fairies (L. Frank Baum)

Our first stop aboard the Arabella is actually underwater.  So, we're going to lower the anchor and prepare ourselves to leap overboard.  This is The Sea Fairies by L. Frank Baum.  The story is centered around a young girl named Trot and her friend, a grizzled old sailor named Cap'n Bill.  One day, as Cap'n Bill is explaining to Trot how no one has ever seen a mermaid and lived to tell of it, a mermaid appears and tells the pair that she had heard what they said, and that the mermaids all agree that they want to prove Cap'n Bill wrong.  After some slight hesitation, Trot and Cap'n Bill jump out of the boat, exchanging their legs for tails, and go on a deep-sea adventure.

Your captain (that's me) will freely admit that I did not finish this book.  I read it back in grade school a couple of times, and remembered liking it.  But, reading it again, I was struck by how slow it was.  While as a child, I would have been dazzled by the beauty of this underwater world, and all the amazing sights to be seen, as an adult, I kept checking my watch, or skimming, or even dozing off in the sunshine while I waited for something, anything to happen.  C'mon, I thought to myself, let's have someone get eaten by a sea monster or get trapped in an underwater cave or something!  But, nothing happened.  Until about 120 pages in, when the evil sorcerer plot started up.  But, by that point, I was kind of done, so I pulled my bookmark and moved on to new adventures.