HMS Thunderer (1872)

HMS Thunderer was a British Royal Navy Devastation-class battleship.

Thunderer was an ironclad turret ship designed by Edward James Reed with revolving turrets, launched in 1872. Thunderer and Devastation were the world's first mastless battleships; armed with four 12-inch guns in rotating turrets and with a central superstructure layout, these ships are the prototypes of all subsequent warships. With 12 inches of ironclad armour from end to end, they weighed over 6,000 tons, despite a length of only 285 feet. Their hydraulic turret machinery and twin screw propulsion - with sufficient coal to provide a range of 4,700 miles - put them in the forefront of mechanical design. The innovations introduced on these ships led to them being regarded with some suspicion, and this was partly justified when two unfortunate accidents clouded the initial success of the design.

On 14 July 1876 shortly after completion she suffered a disastrous boiler explosion which killed 45 people when one of her eight 30 pound per square inch (210 kPa) box boilers burst as she proceeded from Portsmouth Harbour to Stokes Bay to carry out a full power trial.

The explosion killed 15 people instantly, including her captain who was in the boiler room at the time and injured around 70 others, of whom 30 later died. The reason for the explosion was that the pressure gauge was broken and the safety valves had seized through corrosion. The boiler explosion signalled the end of box boilers in favour of the Scotch cylindrical type, and it led directly to the writing of the first official RN Steam Manual in 1879.

Thunderer suffered another serious accident in January 1879 when the left 12 in gun in the forward turret exploded during practice firing in the Sea of Marmora killing 11 and injuring a further 35. The reason for this accident was that the muzzle-loading gun had been double loaded following a misfire, and was a major reason for the Royal Navy changing to breech loading guns. It led to improved loading and handling procedures, and Thunderer herself was re-equipped with long-calibre 10" breech-loaders, and settled down in her old age to become a favourite of the Fleet: King George V served in her for a while as Lieutenant Prince George of Wales. With her broad beam she was a fine gun-platform, and the phrase "As steady as the old Thunderer" was high praise for any newcomer to the Navy.

She was refitted in 1881 and equipped with triple expansion engines, that roughly halved her coal consumption at 80% power (and thus doubled her range), paving the way for the widespread introduction of these engines in the Royal Navy.

Further extensive modifications were carried out in 1890–1892.