above the main deck. 'X' barbette's was 8 inches thick all around. Below the main deck, the barbettes' armour thinned to four inches except for 'A' barbette (eight inches) and 'Y' which remained 11 inches thick. The thickness of the main deck ranged from . The middle deck was thick on the flat and where it sloped down to meet the bottom edge of the main belt. Over the magazine for 'A' and 'Y' turrets it was 3 inches thick, on slope and flat both. The lower deck armour was forward and 2 inches aft where it increased to 3 inches to protect the steering gear. The sides of the conning tower were 11 inches thick and it had a 3-inch roof of KNC. It had a communications tube with 8 inch walls of mild steel down to the Transmitting Station on the middle deck. The walls of the signal tower were 8 inches thick while it had a roof of 3 inches of KNC armour. 2 inch torpedo bulkheads were fitted abreast the magazines and shell rooms of 'A', 'X' and 'Y' turrets, but this increased to 4 inches abreast 'P' and 'Q' turrets to compensate for their outboard location. In common with all major warships of her day, Dreadnought was fitted with anti-torpedo nets, but these were removed early in the war, since they caused considerable loss of speed and were easily defeated by torpedoes fitted with net-cutters. Electrical equipment Electrical power was provided by three 100 kW, 100 V DC Siemens generators, powered by two Brotherhood steam and two Mirrlees diesel engines (which later changed to three steam and one diesel). Among the equipment powered by 100 volt DC and 15 volt DC electrical systems were five lifts (elevators), eight coaling winches, pumps, ventilation fans, lighting and telephone systems. Construction Dreadnought was the sixth ship of the RN to bear the name Dreadnought, which means "fear nothing". To meet Admiral Fisher's goal of building the ship in a single year, material was stockpiled in advance and a great deal of prefabrication was done from May 1905 onwards with approximately 6,000 man weeks of work expended before she was formally laid down on 2 October 1905 on No.5 Slip. In addition, she was built at HM Dockyard, Portsmouth which was regarded as the fastest-building shipyard in the world. The slip was screened from prying eyes and attempts made