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

Mr. Bruce Bell cont'd :

The inclination of the ways would be 1 in 18; this would give 14 x 18 = 252 feet of slipway covered with water in advance of this point, which, in addition to the 300 feet, made 552 feet in all covered by water. Of this 50 feet might be gained by allowing the vessel to over-hang at both ends, and telescoping the steering pieces as the Authors suggested, but it still left 500 feet covered with water, and valueless as dock-floor. It was true that part of this was generally utilised by allowing the last vessel docked to remain on the cradle to be operated upon by tide work. The choice, therefore, between these two forms of dock depended much upon local circumstances and the means at command.

In order to gain additional surface of dock-floor, vessels requiring extensive repairs had in some cases been removed bodily to one side of the slipway. Messrs. Barclay, Curie & Co. worked their slipways on the Clyde for many years in this manner, and in some cases built new vessels on the side of the slipway, and launched them by removing them on to the cradle.

Sir Frederick Bramwell.

Sir Frederick Bramwell said he did not know that he had much to say on the subject of the Paper, but it touched incidentally upon other modes of raising vessels for repair, in which he had some experience. He might say after Abemethy, “ Read my book,” as he believed that the history of the matter, both with regard to slips and to other modes of repair, had been fully dealt with by himself in a Paper read before the Institution of Mechanical Engineers in 1867.

It might be interesting to mention a mode of docking ships for repair mentioned in Belidor’s "Architecture Hydraulique,” in which he suggested that, in lieu of the expense of pumping out a dry dock below the level of the water, there should be, in places where there was a sufficient supply of inland water, a lock made, into which the ship would be floated, and then, the inland water coming in and raising it, it was to be taken into a higher lock, and, the gates being closed, the water was to be allowed to run down ; that was a mode of raising the ship out of the water instead of pumping the water away from the ship. There was a good engraving of it in the excellent edition of the book which was in the Library of the Institution.