While standing through Stronsay Firth in a long, single column, the British squadron, which was in the lead, opened fire on its starboard quarter, its escorting destroyers gathering to drop bombs about a certain spot. Upon signal from the _Princess Margaret_, the starboard wing destroyers of our escort speeded ahead to join the attack, but the port wing destroyers remained on station, although the leading squadron’s destroyers had left theirs. In a few moments, a submarine broached about 1500 yards, two points on _San Francisco’s_ starboard bow, heading across to port, through the column, between the two squadrons. Some destroyers followed and continued bombing. Smoke screens were laid by our escort (_Vampire_, Captain Godfrey, and 11 others of 14th Flotilla) and by our own ships, which thus had a good test for their smoke outfits. _Roanoke_ chanced to have a steering engine disablement just at this moment, causing her to sheer out and shift to hand gear, and the _Housatonic_ also had some steering trouble, but there was no mishap, and the submarine also for the time escaped. By good luck, an official photographer happened to be on board _San Francisco_, and he got some pictures of genuine activity. A delay at the morning rendezvous, the long distance round about, and adverse current combined to make a late mining start. While the mining was in progress, the bodies of two German sailors were passed, and a heavy explosion was observed in the eighth minefield, five miles distant, in a position that plotted in the same place a submarine would be which had been reported shortly before. Darkness shut in about an hour before planting was completed but it caused no suspension nor interference. At the end of the field, buoys were dropped as usual, and all ships together turned left, without signal but on orders given before dark, to the course north, then formed in two columns for the run home. The British and American squadrons had now separated and they passed back through Westray Firth in succession after daylight next morning. Off Pentland Skerries a suspicious craft ahead caused another submarine alarm, and the escort again enveloped the squadron in a smoke screen, but the alarm proved false. This time, the 10 American vessels had planted six lines, two at each of the usual levels, 46 miles long, 5520 mines in all, the maximum of any excursion; the 4 British vessels planted one line at deep level, 1300 mines, 32 miles long, making altogether 6820 mines on the excursion, the largest single minefield ever planted—done in 3 hours and 50 minutes. Upon returning to the bases, Admiral Strauss signaled “The Commander Mine Force congratulates the squadron on this biggest and most successful excursion.” CHAPTER FIFTEEN FINISHING THE BARRIER