German submarine U-491

Had she been completed, U-491 would have been a Type XIV supply and replenishment U-boat ("Milchkuh") of the German Kriegsmarine during World War II.

Her keel was laid down on 31 July 1943, by Deutsche Werke of Kiel. However, extreme losses amongst the existing fleet of Milchkuh submarines led Karl Dönitz to conclude further production of these boats was not a viable plan. All fourteen outstanding orders for type XIV submarines were cancelled. Plans for a type XX Milchkuh were dropped and the thirty planned boats of that class were cancelled.

U-491 was never launched, and was broken up on the building ways after reaching about 75% completion.