around 38,000 men. German invasion Fleet movements The German invasion began on 3 April 1940, when covert supply vessels began to head out in advance of the main force. The Allies initiated their plans on the following day, with 16 Allied submarines ordered to the Skagerrak and Kattegat to serve as a screen and give advance warning of a German response to Operation Wilfred, which was launched the following day when Admiral William Whitworth in set out from Scapa Flow for the Vestfjorden with twelve destroyers. On 7 April, bad weather began to develop in the region, blanketing the area with thick fog and causing rough seas, making travel difficult. Renowns force was soon caught in a heavy snowstorm, and , one of the destroyer escorts, had to drop out of formation to search for a man swept overboard. The weather aided the Germans, providing a screen for their forces, and in the early morning they sent out Gruppe 1 and Gruppe 2, which had the longest distance to travel. Although the weather did make reconnaissance difficult, the two German groups were discovered south of the Naze (the southernmost part of Norway) slightly after 08:00 by Royal Air Force (RAF) patrols and reported as one cruiser and six destroyers. A trailing squad of bombers sent out to attack the German ships found them farther north than they had been before. No damage was inflicted by the attack, but the German group's strength was reassessed as being one battlecruiser, two cruisers and ten destroyers. Because of a strict enforcement of radio silence, the bombers were not able to report this until 17:30. On learning of the German movement, the Admiralty came to the conclusion that the Germans were attempting to break the blockade that the Allies had placed on Germany and use their fleet to disrupt Atlantic trade routes. Admiral Sir Charles Forbes, Commander-in-Chief of the British Home Fleet, was notified of this and set out to intercept them at 20:15. With both sides unaware of the magnitude of the situation, they proceeded as planned. Renown arrived at the Vestfjord late that night and maintained position near the entrance while the minelaying destroyers proceeded to their task. Meanwhile, the Germans launched the remainder of their invasion force. The first direct contact between the two sides occurred the next morning without either side's intention. Glowworm, on her way to rejoin Renown, happened