Despite the industrial revolution, the Royal Navy of the 1880s was largely obsolete. Many warships were still iron clad wooden hulls with rigging and sails to supplement very basic steam engines. Only a few true iron warships had been built.
The Naval Defence Act of Mach 1889 firmly brought the industrial revolution to the Navy. Central to the act was the building of 8 standard battleships of the new Royal Sovereign class, an all-iron design with the most modern armaments, armour and propulsion. It may seem obvious now, but the then revolutionary new concept of standardisation simplified logistics and also facilitated the manoeuvring of these ships as a cohesive fleet. At the time the Royal Sovereign class were the largest warships ever built, displacing 14,190 tons, and made their predecessors in the Royal Navy and other navies obsolete.
Their main armament was 4 x 13.5" guns. On 7 of the sovereigns including the Empress of India these were mounted on armoured platforms or barbettes, one twin gun platform forward and one twin gun platform aft. The design of the Hood was modified slightly, with the fore and aft decks lowered to allow the guns to be mounted in fully armoured turrets. Secondary armament on all ships was 10 x 6" guns mounted 5 on each side.
The lower freeboard of the Hood resulted in poor handling in heavy seas, so she spent most of her active service in calmer waters with the Mediterranean fleet. Nevertheless the overall design of the Royal Sovereign class formed the basis for the later Majestic class, which at 9 ships was the most numerous class of battleship ever built for the Royal Navy.
In 1914 HMS Hood, stripped of armament, was scuttled as a block ship in the south entrance to Portland harbour. The Hood now lies with bows pointing north in 18 metres of water, rising to just 4 metres.
A year earlier in 1913 HMS Empress of India was used as a target for gunnery practice towards the west side of Lyme Bay. She now lies in 50 metres and rises to 35 metres.
As battleships have a habit of doing when sinking, both are the Hood and the Empress of India are completely inverted.
Both situated off the Dorset coast, the Hood and the Empress of India represent the two extremes of compressed air sport diving.