Defiance was a development of the Renown class. The second pair of Renown's, HMS Atlas and HMS Anson, had a modified, finer stern run. Defiance was originally laid down as to the same plan as Atlas, but a new plan dated 8 October 1858 was prepared giving Defiance a lengthened bow. Defiance was the last ship to use the midsection design that Isaac Watts created for HMS James Watt.