Page 31 - Minutes of Proceedings of Civil Engineers Vol CXCV 1913-14 Part 3 Correspondence
P. 31
746 0oRRESPoNDENCE oN THD coNsrRUcrIoN oF [Minutes oI The author. feared that timber alone would sufer seryerely from the glancing blows of n 40,000-ton ship. In reply to questions about the wall for portion O (l'igs. 11, Pldte 2), the reinforced-concrete piles were never seriously damaged by the driving. A sawdust helmet, above which was a short dolly, was used to protect the pile-head. Occasionally the concrete at the pile-head was slightly broken, but as this hnd to be cut away in any case to mould on the beams, no harm was done. Mr. Leitch seemed to think that the driving. of the piles (which was done after the wall in front of them had been ' built up) would increase the lateral pressure on that rvall: but piles driven into earth undoubtedly helped to prevent it from slipping, and if driven behind a retaining-wall it would seem that they should dirninish the latoral pressure, not increase it, Mr. Ilunter antl others had condemned the face batter on tho walls, and the consequent use of floating dummies. Dummies had some advan- tages, however, in a tidal dock, as they enabled the ship's side to be inspected and painted, and they also gave a better Iead for the mooring-ropes. As to the general lay-out of the dock, the Author fancied that the Navigating Officers at Southampton would hardly agreo with Mr. Ilunter's view that the width of 400 feet was excessive. It must be borne in mind that, the dock being laid out for four berths, a vessel night have to pass in or out between two others. A large ship might have four or five tugs in attendance, rrnd it was necessary to have sufficient room for all these craft. The reason why the dock was made 40 feet deep, while the approach- channel rvas only 35 fect, was that this arrangement permitted a vessel like the " Olympic," drawing, say, 35| feet, to lie afloat in the dock evel at an extraordinarrly low spring-tide, whereas the sailing-times did not require her to be in the entrance-channel at such tides, which occurred about 6 p.*. Mr. Wil&ing had made some interesting remarks on the dimensions of the ship of the future. It could be wished that shipowners and dockowners could come to some agreement on this point. It seemed to the Author that the cost of providing dock accommodation for ships increased rnore rapidly than the earnings from the irrcrease in tonnage, and thot if shipowners wished to greatly enlarge the dimensions of their ships the tonnage-dues would eventually have to be raised to uroot the €xpense. In conclusion, the Author wished to thank the corlrlnpondonts, who had contributed facts and criticisms which woro of gt'ont vtlue.
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