From the 15th to the 19th six sloops and seven gunboats were despatched against submarines in the Fair Island Channel and north of the Shetlands, the _Campania’s_ sea-planes again assisting from Pierowall Harbour. Destroyers were also helping during a portion of the period covered by the operations. On the 16th the gunboat _Speedwell_ reported having sighted the periscope of a submarine, ramming her at a speed of 15 knots. The submarine was struck on her starboard quarter at an angle of 10 degrees, but there was, unfortunately, no evidence to show that she was sunk, although it was probable that she was considerably damaged. She was not seen again. On the same day a submarine was reported by the armed yacht _Zaza_, as being in a drift-net 12 miles east-north-east from Fair Island. Local patrol vessels, gunboats and four destroyers concentrated on the position and explosive charges were fired, but without certain result. From the 25th to the 27th a sub-division of destroyers searched, fruitlessly, a large area to the northward of the Hebrides for submarines and a reported submarine base ship. They were assisted by four sloops operating in the area from the 26th to the 30th. On the 18th and 19th a division of destroyers was engaged in moving a neutral fishing fleet away from an area to the eastward of the Firth of Forth where they interfered with Fleet operations. Submarine C 27 had for some little time been operating against submarines in the North Sea from Scapa, in tow of a trawler, to which vessel she was connected by telephone. This idea, which had first been conceived at the Rosyth base, had also been put into operation at Scapa, the arrangements being made under the direction of Admiral Sir Stanley Colville. On July 20th the trawler _Princess Louise_, Lieutenant Morton, R.N.R., being in command, with Lieutenant Cantlie, R.N., a submarine officer, on board, was towing Submarine C 27 (Lieutenant-Commander Dobson) in a submerged condition when a German submarine, U 23, was sighted 1¼ miles off on the port bow. C 27 was informed by telephone, telephonic communication then breaking down. U 23 opened fire at a range of 2,000 yards on the _Princess Louise_. Lieutenant Cantlie, being unable to communicate further with C 27, slipped the tow and proceeded to abandon the trawler with every appearance of haste. U 23 closed to within 600 yards and stopped. Meanwhile, Lieutenant-Commander Dobson, hearing nothing further by telephone, but noticing the splash and explosion of the projectiles in the water, got well clear of the trawler after slipping, and then brought his periscope to the surface for a look around. He sighted U 23 about 900 yards off, closed to a good position for attack within 500 yards, and fired his first torpedo, which missed. His second shot hit; there was a heavy explosion, and U 23 sank; four officers and six men were picked up out of a crew of 34. The whole attack was exceedingly well managed and a very well deserved success