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

The hauling machinery usually consists of one or more direct-acting hydraulic cylinders placed at the top. Water if forced into the cylinder, and the motion transmitted from the rams to the cradle by means of strong forged-iron rods or chains. In some cases engines with gearing are used, especially if the slip be for small vessels.

The mode of working is as follows : -   The general size and description of vessel to be taken on having been ascertained, the bilge-blocks on the cradle are trimmed to fit the ship as nearly as possible, and the guide-rods and other fittings looked to and put in proper position. The cradle is then run down into the water by its own weight, assisted, if necessary, by a down hauling chain worked by an independent apparatus at the top, arranged also for quickly drawing up the empty cradle after launching a vessel. The extreme end of the cradle may project 30 to 50 feet over the end of the rails, the main ribs being made strong enough for this purpose. The vessel is now floated into position as accurately as possible, being guided by hawsers manipulated from the jetty or shore, and also by the fore-guides fixed at the front of the cradle, which are drawn up into the vertical position by ropes afterwards secured on the vessel. The hauling-up then commences, the ship all the time settling on the keel-blocks placed on the centre rib, and being guided at the stern by the aft guides. At the proper time the sliding bilge-blocks are drawn in by ropes previously taken up to the jetties or on board the vessel, and so the operation proceeds until finally the ship is drawn up out of the water, safely seated on the cradle, and supported uniformly over the whole length of keel as well as by the bilge-blocks on each side.

In launching, the reverse process takes place. The vessel is lowered by the machinery to within a convenient distance of the water. The cradle is then disconnected from the links and, the holding pawls being raised, is left supported entirely on one special single pawl or dagger at the top. The dagger is now knocked out by a blow from a hammer, and the cradle with its burden runs down the way till it reaches the water, and the vessel floats off. The empty cradle is drawn up by the supplementary hauling chain, and after trimming is ready to take on another ship.