History of Orkney should continue to be observed in Orkney and Shetland. Thus the udal succession and mode of land tenure (that is, absolute freehold as distinguished from feudal tenure) lingered to some extent, and the remaining udallers held their lands and passed them on without written title. The islands cluster round the huge deep-water anchorage of Scapa Flow like a protecting hand, and in both World War I and World War II, the Royal Navy had a major base there, enabling them to challenge any attempt by German warships to emerge into the ocean through the Norwegian Sea. After the Armistice in
Atlantic U-boat campaign of World War I Atlantic U-boat campaign of World War I The Atlantic U-boat campaign of World War I (sometimes called the "First Battle of the Atlantic", in reference to the World War II campaign of that name) was the prolonged naval conflict between German submarines and the Allied navies in Atlantic waters—the seas around the British Isles, the North Sea and the coast of France. Initially the U-boat campaign was directed against the British Grand Fleet. Later U-boat fleet action was extended to include action against the trade routes of the Allied powers. This campaign was highly destructive, and resulted in the loss