In the strong tides, particularly at night, some such procedure had to be adopted, because the tide was not felt until the ships were clear of Swona Island, and then the effect of it, if running to the westward, and particularly at the period of spring tides, when it has a speed of 10 knots, was to bring a leading squadron or division back on top of that in rear of it. Frequently also a ship, emerging from slack water into the strength of the tide, would be caught by the tide on the bow, and, unless the greatest possible care was taken to watch the steering (and even sometimes in spite of every care), the ship would be turned round through 8, 12 or even 16 points,[F] becoming a danger to those astern of her, as she would be almost unmanageable for a time. Such a situation on a dark night, with a large fleet showing no lights, was not pleasant, and it speaks well for the skill shown in handling the ships that no accident occurred from this cause. [F] 8 points = 90 degrees. The practice in regard to the destroyers, when they accompanied the Fleet (as was necessary after the first twelve months of war), was for the various groups which were detailed by the Commodore (F) to screen the squadrons or divisions of the heavy ships, to meet them just outside the submarine obstruction and screen them from there in daylight, or on moonlight nights, and to form astern on dark nights, in readiness to re-establish the screen at daylight. In the early days of the War, and indeed for the first eighteen months, the practice was for the destroyer flotillas to be stationed some 10 miles from the Battle Fleet at night in order to avoid any chance of their being sighted and mistaken for enemy destroyers; but this procedure caused considerable delay in forming the submarine screen at daylight, and in thick weather the destroyers frequently experienced difficulty in finding the Battle Fleet. Consequently, it became the practice to keep the destroyers actually in company at night, and this procedure was undoubtedly preferable. After the various squadrons had passed the Pentland Skerries, the organisation provided for their taking certain defined routes; the usual practice was to use three routes with the squadrons divided between them, the routes being about seven miles apart. A concentration point, which the squadrons would reach at the ordered speed shortly after daylight, was given in the departure signal, and the squadrons closed in on this point at the appointed time, so that the whole Battle Fleet, including detachments coming from Cromarty, was concentrated shortly after daylight, with the cruisers in their assigned positions scouting ahead. The organisation of the Battle Fleet provided for the strongest squadron being on the eastern flank, because it was considered that the enemy would invariably make towards his bases if touch was gained, and it was desired to have our strongest squadron in the van.