The aircraft cruiser (also known as aviation cruiser or cruiser-carrier) is a warship that combines the features of the aircraft carrier and a surface warship such as a cruiser or battleship. Early types The first aircraft cruiser was originally a 1930s experimental concept of creating an all-around warship. The early aircraft cruisers were usually armed with relatively heavy artillery, mines and a number of aircraft fitted with floats (making the ship a kind of seaplane tender/fighter catapult ship). The early aircraft cruiser turned out to be an unsuccessful design. The rapid development of naval aircraft in the 1930s quickly rendered the vessels obsolete, and they were rebuilt e.g. as anti-aircraft cruisers. A United States design for a flight deck cruiser from 1930, was described as "a light cruiser forwards [and] one half of a aft". Although not built, similar ships were created during and after World War II as reconstructions and later from the keel up. The Japanese built a pair of aircraft cruisers in 1937, the Tone-class cruisers. These ships had their main armament of 4x twin 8" gun turrets placed forward of the superstructure, and an aircraft handling deck was built aft of the funnel. The ships could carry a maximum of 8 float planes, launched by catapult, though the normal complement was 6. During World War II, in part to offset the loss of carriers at the Battle of Midway, Japan rebuilt its s as hybrid carriers, placing the flight deck and hangar aft to replace the rear turrets, while retaining their main guns forward and amidships. The cruiser Mogami also had its rear gun turrets (which had been damaged at Midway) replaced by aircraft handling facilities. The German Kriegsmarine also studied several "Flugdeckkreuzer" (flight deck cruiser) designs in 1942 which included 20.3 cm (8 inch) or 28 cm (11 inch) gun turrets forward of the flight deck. Helicopter cruisers A newer variation of the aircraft carrier is the helicopter carrier, which is capable of operating at least 4 or more helicopters, including medium and heavy lift models. This is in contrast to surface warships such as cruisers, destroyers, and frigates which have basic aviation facilities, including a hangar and landing pad, that are sufficient only for 1–2 light/medium helicopters. Post-war the United Kingdom reconstructed the Tiger-class cruisers, and into helicopter cruisers, retaining their guns forward but having their aft guns removed for the installation of a