The Germans planned to use Vice-Admiral Franz Hipper's fast scouting group of five modern battlecruisers to lure Vice-Admiral Sir David Beatty's battlecruiser squadrons into the path of the main German fleet. They stationed submarines in advance across the likely routes of the British ships. However, the British learned from signal intercepts that a major fleet operation was likely, so on 30 May Jellicoe sailed with the Grand Fleet to rendezvous with Beatty, passing over the locations of the German submarine picket lines while they were unprepared. The German plan had been delayed, causing further problems for their submarines, which had reached the limit of their endurance at sea.