(Here you go Lula.) I read this book as a short, clear-the-palette book between heavier reads. It is a children's book about the ironclad ships that were built during the Civil War. It wasn't that great of a book. Of course I now know more than I ever thought I would about ironclad ships which is actually quite interesting to me, but the book didn't have a strong enough story.
Avi is usually a very good, diverse writer for kids books. He certainly did his research for Iron Thunder as he does for all his other historical fiction books. I would suggest reading his book Crispin The Cross of Lead which won the Newbery (and takes place at the same time our friend Katherine Swynford was alive!), or another really good one of his is The True Confessions of Charlotte Doyle. It's about a girl in the mid 1800's who accidentally ends up on a ship of men travelling from England to the USA. It is a Newbery Honor Book.
Iron Thunder gets a C- or D+ from me. But read the other two! They are good!