Meantime, the original plan had, in London, undergone considerable modification as to the constitution of the barrage. Originally of three systems, each comprising three lines of mines—upper, middle, and lower levels—the necessity which had developed for wider spacing between mines, to avoid structural damage to neighboring mines when one was detonated—300 feet instead of 150, as originally planned—made it seem desirable to increase the number of lines of mines, so as to maintain the same density of the mine barrage as a whole. The revision aimed to increase the risk to surface passage considerably. No effective patrol being maintained along the barrage, submarines would naturally prefer the surface. The revised plan, in brief, made 10 upper level rows instead of 3, and 4 middle and 4 lower level, instead of 3 each, or a total of 18 rows instead of 9. Rather than shorten our line and again employ only part of the squadron, the Commander of the Mine Force took up the revised scheme at once, ordering 5400 mines prepared, for a field of 5 parallel lines 54 miles long. All 10 ships were loaded nearly to full capacity, _Housatonic_ taking 840 mines. Departure was taken at 2 p.m., Sunday 14 July, hauling down, as we got underway, the dress bunting which had been hoisted in honor of the French Bastille Day. CHAPTER ELEVEN TACTICS Ten ships laden with high explosive, navigating in mine-swept channels, in submarine thoroughfares, and near minefields beyond sight of fixed marks—compactness of the minefield demanding that the layers steam as near together as safe—necessity for keeping together in fog, darkness, or submarine attack—these were the conditions governing our tactics. Thus, the mining excursions were not merely arduous in preparation and execution. Precision and quickness of action while at sea were imperative, from start to finish. To foster these, a steady tension was kept up throughout the squadron, a tension which likewise helped the individual ships to maintain a careful habit among the men, without making them jumpy or fearful. To sustain attention and prevent over-confidence growing with familiarity, unremitting pains were exercised to note and correct any irregularity or apparent slackness—not to find fault but to keep things taut everywhere. Only in this way could compliance with all details be insured—so very important in our work. From assembly at the buoy until the return to it after the excursion, the _San Francisco_, leading the squadron, would maintain a steady pace, sometimes increasing to make up for adverse current, but rarely slackening speed for anything. The squadron’s position was frequently compared with the time schedule, and no effort was spared to carry through the excursion with precision. There was time enough, we had speed enough, but none too much of either, and the whole body felt a constant urge towards a direct and clean-cut movement out to the field, over it, and back to the base.