Page:Victory at Sea - William Sowden Sims and Burton J. Hendrick.djvu/265

1917-18] used up to that time—the same design which was used in the American navy—was defective. But the process of developing new mines in war-time had proved slow and difficult; and the demands of the army on the munition factories had prevented the Admiralty from obtaining a sufficient number. The work of the Dover patrols was a glorious one, as will appear when all of the facts come to public knowledge. But in 1917 this patrol was not preventing the U-boats from slipping through the Channel. The Straits of Dover, at the point where this so-called barrage was supposed to have existed, is about twenty miles wide. The passage-way between Scotland and Norway is 250 miles wide. The water in the Channel has an average depth of a few fathoms; in the northern expanse of the North Sea it reaches an average depth of 600 feet. Mining in such deep waters had never been undertaken or even considered before by any nation. The English Channel is celebrated for its strong tides and stormy weather, but it is not the scene of the tempestuous gales which rage so frequently in the winter months in these northern waters. If the British navy had not succeeded in constructing an effective mine barrier across the English Channel, what was the likelihood that success would crown an effort to build a much greater obstruction in the far more difficult waters to the north?

The one point which few understood at that time was that the mere building of the barrage would not in itself prevent the escape of submarines from the North Sea. Besides building such a barrage, it would be necessary to protect it with surface vessels. Otherwise German mine-sweepers could visit the scene, and sweep up enough of the obstruction to make a hole through which their submarines could pass. It is evident that, in a barrage extending 250 miles, it would not be difficult to find some place in which to conduct such sweeping operations ; it is also clear that it would take a considerable number of patrolling vessels to watch such an extensive barrier and to interfere with such operations. Moreover, we could not send our mine-layers into the North Sea without destroyer escort; that is, it would be necessary to detach a considerable part of our forces to protect these ships while they were laying their mines. Those responsible for anti-submarine operations believed that in the spring and summer of 1917 it would