The next day he wrote a long letter, amplifying the difficulties and reporting against any such barriers. But our ordnance experts were thoroughly convinced the project was feasible. On May 9th they outlined their plans in a memorandum to be submitted to the British Admiralty, and on May 11th I cabled to Admiral Sims: "Much opinion is in favor of concerted efforts by the Allies to establish a complete barrier across the North Sea, Scotland to Norway, either direct or via the Shetlands, to prevent the egress of German submarines." I added, "The difficulty and size of the problem is recognized, but if it is possible of accomplishment the situation would warrant the effort." He was directed to consult with the British Admiralty regarding this plan. Two days later came the reply: From all experience Admiralty considers project of attempting to close exit to North Sea to enemy submarines by the method suggested to be quite impracticable. Project has previously been considered and abandoned. In a dispatch on May 14th Sims said: "The abandonment of any serious attempts at blockading such passages as Scotland-Norway, the Skagerrack and Scotland to Shetland has been forced by bitter and expensive experience." "As may well be imagined," he wrote later, "this whole subject has been given the most earnest consideration, as it is, of course, realized that if submarines could be kept from coming out, the whole problem would at once be solved." But he said, "I cannot too strongly emphasize the fact that during nearly three years of active warfare this whole question had been the most serious subject of consideration by the British Admiralty," which had concluded that no "barrier can be completely effective." This, however, did not deter our ordnance experts. The more they studied the question, the more were they convinced that the barrier could be "put across." Believing in mines, preparing for mine operations on a large scale, they were astonished when, on May 31st, Sims reported that, instead of our giving attention to mine production, the British Admiralty "consider we can more profitably concentrate on other work."