Volume Ten - Pre-Victorian to the present day - even more aspects - The Patent for the Penarth Slipway - 1881 . . .

For example, the four graving docks recently constructed at Spezzia had cost £312,000, or nearly £80,000 each, and the Somerset dry dock at Malta had cost £150,000. Such cases, however, were very exceptional ; and the same might be said of some of the floating docks recently constructed — notably the iron floating dock weighing 4,500 tons, constructed at a cost of £132,000 by Schneider and Co. at Creusot for Saigon in Cochin China. Those costly works being expressly built to accommodate the largest men-of-war afloat, could not, of course, be usefully compared with slipways and docks built exclusively for the purposes of merchant and passenger steamers.

After considering some of the advantages and disadvantages of slipways compared with other arrangements for the repair of ships, he thought it might be fairly said that, except in special cases, the provision of a dry dock was more advisable than that of a slipway in a locality where some of the vessels requiring repair exceeded a length of 300 feet or 2,000 tons displacement.

That opinion was strengthened by a letter that he had received from a large firm of shipowners in the north of England, an extract from which he might be permitted to read : —

“ We decidedly demur to haul a ship of 350-feet length up a patent slip if a floating or a dry dock could be had. We should consider such a vessel liable to strain by being put upon a slip, although we believe that it is occasionally done, for by enquiry which we have just made we find that a steamer of 300 feet in length has been put upon the Wallsend Slipway at Newcastle without any bad results whatever — but they have not had a longer one on. We may mention, however, that this slipway is of recent construction and probably one of the best in the kingdom.”

He fully agreed with the Authors that in setting up a shipbuilding establishment, the choice of a plan should be left entirely to the engineer, after he had made a careful study of the locality, as in all such cases the chief merit would deservedly belong to those who, after a long and patient study of different systems on the ground, chose the method best adapted to the special circumstances of the site where economical first-class ship accommodation was urgently needed.