The Naval High Command (Oberkommando der Marine or OKM), commanded by Admiral Erich Raeder, intended to continue the practice of using heavy ships as surface raiders against Allied merchant traffic in the Atlantic Ocean. The two Scharnhorst-class battleships were based in Brest, France, at the time, having just completed Operation Berlin, a major raid into the Atlantic. Bismarck's sister ship Tirpitz rapidly approached completion.