(ii)
her own draft over the rock, and when the NE-going stream was likely to be still far too strong to be safely carried through. It follows that such a lengthy outward tow only becomes a practical proposition during the extended 'Slack' of the smaller tides, avoiding anything bigger than a middle height tide (say 8.0M at Liverpool when the depth over Cheese Rock would be around 21 ft(Fig.8)), which after allowing Emrys' "absolute minimum" 2 ft underkeel clearance forces the conclusion that the channel isn't really suitable for any 20 minute outward tow deeper than 19 feet.(see Note 15) Even this is deeper than anything which has ever passed outward through these waters up to the time of writing (November 2004).
Although proven to be possible, the inbound transit was bordering on the foolhardy and Capt Goddard very nearly lost her then.(Goddard Text2) But he had passed over the rock right on top of HW with 3' 6" under his keel, and with the tide behind him without any fear of being defeated by a contrary stream. By contrast page 6a explains why the outbound tow would necessarily need to start 20 minutes earlier on the tide, which after allowing Capt Goddards 18 minutes to reach the rock meant the outbound ship would have to pass over the rock 40 minutes sooner with 3 ft less water!!Page 6b Add to this a). An extraordinary spring tide which would be turning against her, and b). The following stream which at the required time of entry on a big tide might still be too strong to pass under the bridge as much as 20 minutes before the 'Slack', and in every respect a 20 minute outward tow so excessively deep as to be limited to an equinoctial spring tide was so marginal as to be impractical.
Examining the chart shows the bottom in the area Cribben Gutter/Britannia Bridge to be highly irregular. There were only a few small rocky upstands to be flattened and the situation would have been transformed. Since the difference between the highest and lowest tides of the year was only 4' 9",(page 14) it only needed the upper 5 ft of these few upstands to be removed and there's no reason why the ship should not have made the transit during the extended 'Slack' of a docile neap tide,(Sherwin) and in any case well away from the severe streams and brief period of 'Slack' associated with the highest tides. However, the unavoidable use of underwater explosives which this would entail so close to the footings of Britannia Railway Bridge rendered this quite unlikely to have been an option.(see note 17)
2/. Politics? : But Management's priorities had switched away from the ship towards putting down roots at Plas Newydd upon which the future of the Establishment depended. Once achieved, even in 1949 the time could already be envisaged when the ship would become a costly and unneccessary surplus to requirements.(see note 16) Capt Goddard was reasonably confident about the inbound transit ("I was very glad when it was accomplished")(Goddard page_233) and they were not going to be deterred by doubts about the outward tow. Once the ship had gone through to Plas Newydd the prospects for her eventual outward transit, while not impossible, must have been regarded as borderline at best, ("the North Wales seafaring fraternity who had declared the undertaking to be a foolish one")(Goddard page 233) and once at Plas Newydd her safe extraction could only be guaranteed by some unidentified extraordinary proceedures which could not include deepening the channel. If in sending the ship inbound Management was fully aware of this, as indeed was its duty to be, that highly contentious information never passed beyond the Committee Room door.
3/. The Weather : Yet given the ideal conditions of a very low barometer and a healthy wind from the southwest (which would have delayed and attenuated 'The Slack', increased the depth of the water and weakened the SW-going stream) the outward transit was not impossible. But conditions on the day were the complete opposite with pressure about the seasonal norm and a force 6 increasing 7 (gusting 10) from the northwest.(Bidston) Nevertheless, had the ship proceeded 20 minutes earlier as Pilot advised there's no reason to doubt that she would have reached the Suspension Bridge, but that still left a long way to tow against what turned out to be an accelerating tidal surge that morning, without any guarantee that she might not have piled up somewhere in the populated area on the other side of the bridge with even more disasterous results. So the percieved need for the (predicted) 'highest tide of the year' had overshaddowed the equally important consideration of suitable weather, with the result that the transit was attempted in the worst possible wind which not only promoted the severe tidal conditions the ship was to run into that day, but ironically would also have left the tide in all South Irish Sea areas significantly below predicted levels.