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

Water from the accumulator having been admitted to one or more of the main hauling-rams, according to the weight and position of the vessel on the ways, the crosshead is pushed up, forcing the ram into the returning cylinder and drawing up the links.

On reversing the valve-lever, the pressure is shut off and the main cylinders opened to exhaust, so that the constant-pressure ram reverses the stroke, forcing in the main rams and pushing down the links to the position from which they started.

A definite upward and downward travel, equal in length to the stroke of the rams, can therefore be given to the links by the forward or backward movement of the hand-lever.

◊ Slipways for Repairing Ships - Plate 5 - Figs. 5 and 6.

From Plate 5, Figs. 5 and 6 it will be seen that the links are jointed with rectangular flat plates, and as all links and plates are made of equal length, it follows that if suitable pawls are fixed to the cradle, and arranged to gear with the ends of the joint-plates, the cradle will be drawn up at each upward stroke of the rams, while during the downward motion of the links the pawls will slip, the cradle remaining in its highest position, being held by the pawls in gear with the rack cast in the centre line of rails.

The hauling pawls, of which several sets are used, are shown in elevation in Plate 5, Fig. 6, and are made of forged iron secured to the main rib by cast steel or malleable cast-iron brackets.