In these circumstances the Admiralty in ’68 determined to consider both types, with a view to embodying the best arrangement in the new class of vessels then projected. The principal shipbuilders of the country were invited to compete, and were presented with specifications for a first-class warship so widely drawn as to leave them the greatest latitude in design. Of the seven designs submitted, three were of the central-battery type, three were turret ships, and one a compound of the two. After comparison with an Admiralty design produced by Sir Edward Reed, it was decided to adopt this in preference to those of the private firms, and to build a whole class of six ships to it. The result was the _Audacious_ class--of which the best-remembered are the _Iron Duke_ and the ill-fated _Vanguard_. In this class a strong all-round fire was obtained by arranging two central batteries of the same size, one on the main and one on the upper deck. The main deck battery had only broadside ports for its six 12-ton guns, each gun training thirty degrees before and abaft the beam; the upper deck battery had four guns of the same calibre mounted at ports cut in armour facets at forty-five degrees with the keel-line, and training through ninety degrees. To allow axial fire from these guns the upper battery was made to project slightly, sponson fashion, over the sides of the ship, and the bulwarks forward and aft of the battery were set slightly back toward the centre line to enable the guns to fire past them.