Having decided _where_ and _how_ things should be done, the remaining question was _when_ they should take place. The operation with its various phases and diversions could not be carried out on the go-as-you-please principle. Every item needed to be carefully fitted in to suit the remainder. The timing of each event was of paramount importance. A long-range bombardment or an aerial attack, if delayed, might destroy our own vessels. The blowing up of the viaduct was calculated to render _hors de combat_ all human beings within a certain distance--our own men on the Mole must not be endangered by it. It would be useless for the blockships to arrive before the fire of the Mole batteries had been suitably diverted. Aerial bombers flying at a hundred miles per hour could not accompany the ships steaming at about one-tenth of that speed. The line of fire from the bombarding vessels could not very well coincide with our approach course, hence the necessity for the monitors to take up independent positions. And so on. How could a satisfactory synchronisation of events be arranged?--that was the problem. There were only two methods to consider: firstly, that of centralised command by signal; secondly, that of working in accordance with a prearranged time table. The former method was obviously impracticable. Signals passed by either the wireless or visual method, during the approach, would make our presence known to the enemy and thus preclude all chance of taking the latter by surprise. After the attack had commenced signals would be impracticable for obvious reasons, chief amongst them being the deafening noise {138} and the presence of artificial fog. So direction by signal could be ruled out. [Sidenote: The Timing Question] Recourse was had to the time-table method. A table was made out showing the exact times (by clock) that the main force was to pass through various positions and to arrive at the several destinations. All other movements were to synchronise according to plan. The time table naturally varied for each day according to the projected time of arrival of the blockships, this, in turn, depending on the time of high tide. But that was not all. It was necessary to guard against unexpected delays due to accident, and against vagaries of the tidal stream. Every unit should know, at a late stage of the oversea trip, if the blockships were likely to be late or early, and the probable difference between actual and projected time involved.