The First Air Fleet, the task force that was to undertake the Hawaii Operation, was protected by the battleships Kirisima and Hiei, sister ships. Hiei was laid down on 4 November 1911 and completed on 4 August 1914. Her displacement was 29,330 tons, her length overall 704 feet and beam 92 feet. She carried eight 14-inch and 16 6-inch guns, eight 5-inch anti-aircraft guns and other light guns as well as four 21-inch torpedo tubes. The battleships sailed in the rear of the formation and Hiei, which had the best reception, picked up radio messages from Tokyo and relayed them by flag or blinker (signal light) to the rest of the fleet.
See also: First Air Fleet
You can find out more about the Hiei in the following Osprey book: