Fig. 5. Anchor paying out mooring cable as it sinks. Plummet strikes bottom and locks cable drum.
Fig. 6. Anchor on bottom submerging mine distance equal to length of plummet cord.
A. MINE CASE
B. ANCHOR
C. PLUMMET
D. PLUMMET CORD
E. SLIP HOOK
F. MOORING
The barrage did more than take toll of submarines sent to kingdom come by its mines. "There is no doubt," reported Sims in the "Summary of Activities of American Forces in European Waters," "that the barrage had a considerable moral effect on the German naval crews, for it is known that several submarines hesitated some time before crossing. Also, reports from German sources are that the barrage caused no small amount of panic in some of the submarine flotillas. It is also probable that the barrage played a part in preventing raids on Allied commerce by fast enemy cruisers."
Admiral Strauss, in his testimony before the Senate Investigating Committee, declared that if the Northern Barrage and that across the Straits of Dover had been fully completed as we planned, "it would have ended the submarine menace, so far as submarines going from the North Sea into the Atlantic were concerned;" and that the building of the mine barriers across the Adriatic and Aegean seas, for which we were preparing materials, "would have actually ended submarine operations."
Could it have been built in 1917, a year earlier than it was? Strauss said it could, and this was the firm belief of Earle and other ordnance experts. True, the antenna mine we developed later was a big improvement, superior to any previously devised. It would have taken two or three times as many mines of the type then in use, perhaps 180,000 of them, as was estimated. We manufactured 100,000 of the antenna type, and could have made as many more, if necessary. The British had no antenna mines, Admiral Strauss pointed out, and all the mines they laid in the barrage were of the older type. After all the objections were presented to him, Admiral Strauss, when asked if he still considered it would have been feasible to have gone ahead with the barrage in 1917, unhesitatingly answered: "Yes."
Not laying that barrage earlier—in fact, at the earliest possible moment—was, in my opinion, the greatest naval error of the war. If the British had erected it early in the war, and put a similar effective barrier across the Straits of Dover and Otranto, the Germans would have been so restricted that widespread U-boat warfare, with its terrible destruction of life and shipping, would have been impossible.
"Shutting up the hornets in their nests," as President Wilson expressed it, was the first idea that occurred to us when we went to war. The Bureau of Ordnance on April 15, 1917, submitted a memorandum urging that we "stop the submarines at their source" and suggesting that mine barriers be laid across the North Sea, the Adriatic and the Dardanelles. "The northern barrier," it stated, "would extend from the mid-eastern coast of Scotland to the Norwegian coast, a distance of about 250 miles," and the southern (that is, to close the Straits of Dover) would extend "from the southeast coast of England and to a point on the French coast near the Belgian frontier, a distance of about forty miles." Next day I cabled Admiral Sims, who had just arrived in London:
Is it not practicable to blockade German coast efficiently and completely, thus making practically impossible the egress and ingress of submarines? The steps attempted or accomplished in this direction are to be reported at once.
Two days later came the answer: