. "U-D4 was a O 21-class submarine. The boat was laid down as the Dutch submarine K XXVI and renamed O 26 but was captured during German invasion of the Netherlands in World War II and commissioned in the Kriegsmarine."@en . . . . . . . . . . . . . . "--04-20"^^ . "U-D4"@en . . . . "German submarine U-D4"@en . . "U-D4 was a O 21-class submarine. The boat was laid down as the Dutch submarine K XXVI and renamed O 26 but was captured during German invasion of the Netherlands in World War II and commissioned in the Kriegsmarine."@en .