The consensus of British naval opinion after the Crimean War favoured the large steam-powered two-decker line-of-battle ship with 101 or 91 guns.

The 91s were given similar engines, while their smaller increase in size was largely taken up with an additional 15 feet (4.6 m) overall for a finer length-to-beam ratio and improved lines in HMS Defiance.

Nevertheless, the Royal Navy continued to convert old sailing line-of-battle ships to steam, and to order and lay down new Bulwark-class two-deckers.

[6] So it was prudent to continue building unarmoured steam line-of-battle ships, which would in any case be "the common currency of sea-power for some years to come.

[9] completed as Prince Consort Bulwark and Robust were suspended on the stocks in March 1861 in an advanced state of construction.

The Controller "had plans prepared for the Bulwark to be converted into a twin turret breastwork monitor but they were never used.

As Edward Reed pointed out this was a wise policy as they would have been inferior to, and yet more costly than, iron-hulled ships built from scratch.