Revell 05078 Deutsches U-Boot German Submarine Type XXI with Interior Scale 1/144. The Type XXI U-boats were German ocean-going submarines whose serial production began in 1944. The Type XXI units were 76.7 m long, 6.6 m wide and had an underwater displacement of 1,820 tons. The maximum speed on the surface of the Type XXI U-boats was 15.6 knots, and the maximum speed underwater was 17.2 knots! The main armament of the Type XXI units consisted of six 533 mm torpedo tubes located in the bow. Secondary armament is 2 twin 20mm AA guns or 2 twin 30mm AA guns. The Type XXI U-boats were created in connection with the increasing losses suffered by German submarines in the Battle of the Atlantic, linked to the use of increasingly sophisticated methods by the Western Allies (Combating Submarines). The command of the Kriegsmarine in 1943 decided to create a completely new type of submarine, which turned out to be a technological breakthrough in the construction of this type of unit. First, a large-scale modular structure was used, which significantly reduced the production time of a single vessel. Furthermore, a new type of propulsion was used and a much better hydrodynamic shape of the hull and kiosk was taken care of, which allowed the phenomenal underwater speed of 17 knots for those times! The Type XXI ships also had a long range, a very large maximum depth, and were much quieter than previous German submarines. They also had rich - as at the end of the Second World War - electronic equipment. All these qualities made them an extremely dangerous weapon against Allied merchant shipping in the Atlantic. However, considerable production delays, the Western Allies' offensive bombing of Germany, and the loss of Atlantic ports in 1944 meant that the first Type XXI ships did not enter operational service until March 1945! However, after the end of the Second World War, the acquired copies were intensively studied by the Americans, British and Russians and, to a large extent, marked the development of submarines in these countries until the end of the 1950s!