Dreadnought was originally named Fury and was designed by the Director of Naval Construction (DNC), Sir Edward Reed, as an improved and enlarged version of the preceding Devastation-class ironclad turret ships.

[3] The main changes were to increase the beam by 18 inches (457 mm) and widen Reed's armoured breastwork to cover the full width of the hull.

This increased the ship's freeboard amidships which improved buoyancy and stability and provided additional, badly needed accommodation for the crew.

In addition, the maximum thickness of the armour was increased from 12 to 14 inches (305 to 356 mm), it was extended all the way to the bow and reinforced the ram.

Barnaby and White's initial plan was to extend the breastwork fore and aft, almost to the ends of the ship, but this was changed to run all the way to the ends after the results of Devastation's sea trials in 1873–74 revealed that her low bow caused major problems in head seas.

Other changes was the substitution of more economical inverted vertical compound-expansion steam engines for Reed's original horizontal, low-pressure engines, more powerful 12.5-inch (320 mm) guns for the 12-inch (305 mm) ones first chosen, and the fitting of hydraulic pumps to work the gun turrets.

[5] Dreadnought was the first ship to have a longitudinal watertight bulkhead that divided the engine and boiler rooms down the centreline.

Dreadnought's engines were powered by a dozen cylindrical boilers with a working pressure of 60 psi (414 kPa; 4 kgf/cm2).

Dreadnought reached a maximum speed of 14.5 knots (26.9 km/h; 16.7 mph) from 8,216 ihp (6,127 kW) during her sea trials.

The ship carried a maximum of 1,800 long tons (1,829 t) of coal, enough to steam 5,650 nautical miles (10,460 km; 6,500 mi) at 10 knots (19 km/h; 12 mph).

The 184-foot-long (56.1 m) armoured citadel protected the bases of the gun turrets, the funnel uptakes and the crew's quarters.

[15] The renamed ship was launched on 8 March by Agnes Wood, daughter of William Courtenay, 11th Earl of Devon.