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

Thompson’s System - This system, designed by Mr. John Thompson of Newcastle, and Mr. T. B. Lightfoot, by whose firm the machinery was constructed, is now in use at the slipways of Messrs. Cleland and Co., and Messrs. Palmer’s Shipbuilding Company, on the Tyne ; at Penarth Docks ; and at Messrs. Raylton Dixon and Co.’s Works, Middlesborough.

◊ Slipways - Thompson's system - Plate 80 - Figs. 8, 9, 10 and 11.

It consists of a treble-powered hydraulic hauling apparatus, Figs. 8 and 9, Plate 80, placed at the top of the ways, and connected by means of suitable crosshead and rods to a double set of main traction links, which extend nearly to the bottom of the ways. The three powers are obtained by allowing the pressure (which may be taken either direct from a pump or from an accumulator) to act respectively on the centre ram alone, on the two outer rams, or on all three together.

The rams are single acting, and the water is admitted or exhausted by the attendant, controlling an ordinary hydraulic working valve. The return stroke is accomplished by means of a small single-acting hydraulic cylinder, on the ram R of which the pressure water constantly acts.

The connection to this ram R is in some cases made by chains, Fig. 10, attached to the extreme end of the links, and carried round suitable pulleys up to the returning cylinder, which is fixed above low water.

In other cases, Fig. 11, the ram R is applied direct to the crosshead of the hauling cylinders, rods or chains being taken down the whole length of ways to the bottom end of the links, so as to transmit the proportion of power required for hauling them down the ways.