In late 1917, light forces of the High Seas Fleet began interdicting British convoys to Norway. On 17 October the light cruisers and intercepted one of the convoys, sinking nine of the twelve cargo ships and the two escorting destroyers before turning back to Germany. On 12 December, four German destroyers ambushed a second British convoy of five cargo vessels and two British destroyers. All five transports were sunk, as was one of the destroyers. Following these two raids, Admiral David Beatty, the commander of the Grand Fleet, detached battleships from the battle fleet to protect the convoys. The German Imperial Navy ("Kaiserliche Marine") was now presented with an opportunity for which it had been waiting the entire war: a portion of the numerically stronger Grand Fleet was separated and could be isolated and destroyed. Hipper planned the operation: the battlecruisers of I Scouting Group, along with light cruisers and destroyers, would attack one of the large convoys, while the rest of the High Seas Fleet would stand by, ready to attack the British dreadnought battleship squadron.