In considering the Anti-Submarine work of the destroyers, it must be remembered that hunting is not, generally speaking, their first object. They are out, not for sport, but for ‘business as usual.’ They have a large number of U-boats to their credit, but in most of these cases the kill was incidental; it resulted from the perfection of skill and smartness with which some professional duty was being performed, at the moment when the opportunity occurred. A few typical examples will make this clear.
In August 1917, an upward sweep of the Norwegian coast was being carried out by a light squadron, consisting of three cruisers and six destroyers, the whole under the orders of H.M.S. _Yarmouth_, Captain Thomas D. Pratt, R.N., with Commander Geoffrey Corbett, R.N., as Senior Officer of Destroyers. The light cruisers were in line abreast, visibility distance apart--anything from five to ten miles--and each was screened by two destroyers. The cruiser on the port wing was _Birkenhead_, and the destroyer on her port bow was the _Oracle_, which was therefore outside ship of the whole squadron.
Just before dark, Lieutenant-Commander A. Grendon Tippet, R.N., commanding _Oracle_, was informed that very strong German wireless from two different sources was being intercepted; and as one of the sources was evidently near by, he decided to keep all hands closed up to their quarters throughout the night. Nothing, however, happened until broad daylight, when, at about 6 A.M., Lieutenant Claude Butlin, officer of the watch, sighted a vessel on the horizon. No one else on the bridge could see it, but Mr. Butlin reported it, and his captain, who knew his exceptional alertness and powers of vision, ordered him to continue the look-out and report again. Shortly afterwards the vessel was sighted by the midshipman and the signalman of the watch, and was pronounced to be a trawler.
But a few minutes after this Mr. Butlin saw a bow and stern lift out of the water, well to left and right of the vessel’s sail, and decided that she was a submarine. He at once informed his commander, who ordered full speed, course to be altered, and the proper signals to be made. The sail then disappeared, and the submarine’s conning-tower became clearly visible, at a distance of something under seven miles.