I have been reading Carry On, Mr. Bowditch by Jean Lee Latham with the boys and they are really enjoying it. OK, I have been, too. It's the story of Nathaniel Bowditch and his contributions to ocean navigation. It's also a great story for kids since Bowditch had to overcome so much in his life. He overcame obstacles "sailing by an ash breeze," a term referring to the use of oars when a ship was becalmed.
The book's readability level is listed as 5th grade, but my 2nd and 4th grader understand things just fine with some extra help on terms and meaning. There's a helpful study guide available online, too. There are many tangents we have explored as well, such as geography, nautical terms, and American history. Highly recommended.
From the back cover:
In her Newbery Media-winning book, Jean Lee Latham chronicles Nathaniel Bowditch's journey, from his modest beginnings, to his first sea voyage, to his rigorous self-education, to the triumphs of his fine-tuned mastery of navigation and eventual publication of his famous work, The American Practical Navigator (also known as the "Sailor's Bible"). Nat's amazing discoveries and accomplishments are brought to life for generations of readers in this engrossing maritime biography.