Complex sentence: The ships of this class were designed by the Bureau of Construction and Repair, and although unfortunately they were wooden-hulled,, the only one to take part in the Civil War, was usually considered the best of the U.S. monitors.
Split into simpler sentences: The ships of this class were designed by the Bureau of Construction and Repair, and were wooden-hulled. The, the only one to take part in the Civil War, is usually considered the best of the U.S. monitors.