The Naval Defence Act 1889 resulted in orders being placed for 21 second-class protected cruisers of the Apollo-class, together with 8 of the larger and better armed development, the Astraea class.
The Apollo-class were an enlarged version of the Marathon-class cruiser built under the 1887–1888 shipbuilding programme.
Three Apollos, Indefatigable, Iphigenia and Intrepid were ordered from the London and Glasgow Shipbuilding Company.

Indefatigable was one of 10 ships of the class that were sheathed in wood and copper to reduce fouling when serving in tropical waters.
She was 314 ft 0 in (95.71 m) long overall and 300 ft (91.44 m) between perpendiculars, with a beam of 43 ft 8 in (13.31 m) and a draught of 18 ft 6 in (5.64 m).
Displacement was 3,600 long tons (3,700 t).
Five cylindrical fire-tube boilers fed steam to two Triple-expansion engines rated at 7,000 ihp (5,200 kW) natural draught and 9,000 ihp (6,700 kW) with forced draught.
This gave a design speed with forced draught of 18.75 kn (21.6 mph; 34.7 km/h).

An armoured deck of between 1 ¹⁄₄ inches (32 mm) and 2 inches (51 mm) protected the ship's magazines and machinery, while the ship's conning tower had 3 inches (76 mm) of armour and the gunshields 4 ¹⁄₂ inches (110 mm).
Two QF 6-inch (152 mm) guns were mounted fore and aft on the ship's centreline, while six 4.7 in (120 mm) guns were mounted three on each broadside.
8 six pounder guns and 1 three pounder provided protection against torpedo boats.

Indefatigable was laid down as Yard number 264 at London and Glasgow's Govan shipyard in 1890 and launched on 12 March 1891 and completed in 1892.
The Naval Defence Act 1889 resulted in orders being placed for 21 second-class protected cruisers of the Apollo-class, together with 8 of the larger and better armed development, the Astraea class. The Apollo-class were an enlarged version of the Marathon-class cruiser built under the 1887–1888 shipbuilding programme. Three Apollos, Indefatigable, Iphigenia and Intrepid were ordered from the London and Glasgow Shipbuilding Company. 
Indefatigable was one of 10 ships of the class that were sheathed in wood and copper to reduce fouling when serving in tropical waters. She was 314 ft 0 in (95.71 m) long overall and 300 ft (91.44 m) between perpendiculars, with a beam of 43 ft 8 in (13.31 m) and a draught of 18 ft 6 in (5.64 m). Displacement was 3,600 long tons (3,700 t). Five cylindrical fire-tube boilers fed steam to two Triple-expansion engines rated at 7,000 ihp (5,200 kW) natural draught and 9,000 ihp (6,700 kW) with forced draught. This gave a design speed with forced draught of 18.75 kn (21.6 mph; 34.7 km/h).
An armoured deck of between 1 ¹⁄₄ inches (32 mm) and 2 inches (51 mm) protected the ship's magazines and machinery, while the ship's conning tower had 3 inches (76 mm) of armour and the gunshields 4 ¹⁄₂ inches (110 mm). Two QF 6-inch (152 mm) guns were mounted fore and aft on the ship's centreline, while six 4.7 in (120 mm) guns were mounted three on each broadside. 8 six pounder guns and 1 three pounder provided protection against torpedo boats.
Indefatigable was laid down as Yard number 264 at London and Glasgow's Govan shipyard in 1890 and launched on 12 March 1891 and completed in 1892.
HMS Indefatigable (1891)