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

This Invention consists of a mode of constructing the cradles and longitudinal sloping rails or " ways," in such a manner that a ship having been hauled up to a certain point upon the main cradle can be transferred to an auxiliary cradle, the main cradle being thereby liberated to receive another ship.

With this object in view we construct the main rails or ways of the slipway and the cradle running upon them in the ordinary manner and at the necessary slope or inclination, but of such additional length as may be required for the working of the auxiliary cradle upon its rails or ways, as next described. Alongside the upper portion of the main rails or " ways ," and parallel with them, we place auxiliary rails or ways with the auxiliary cradle running upon them.

The slope or inclination of these auxiliary rails or " ways " is greater than that of the main rails or " ways, " to such an extent that when a ship has been hauled up on the main cradle until she is over the auxiliary cradle and " bilge " blocks have been fitted between the ship and such cradle, and the arms of the main cradle have been swung round and laid over the side rails, when the further heaving up of the two cradles simultaneously causes the ship to be gradually lifted off the main cradle by the increased inclination of the rails or " ways " upon which the auxiliary cradle is travelling, until the ship is quite clear of the main cradle and her whole weight is bourne by the auxiliary cradle. The main cradle is then at liberty to be lowered down the " ways " and launched to receive another ship, the auxiliary cradle with the ship resting on the upper portion of the slipway.

When the ship on the auxiliary cradle is to be launched, the main cradle with the arms swung round and resting on the side walls is hauled up under the ship, and the main and auxiliary cradles and simultaneously lowered down the "ways; " the greater inclination of the ways of the auxiliary cradle causes the ship to gradually approach and seat itself on the resting blocks of the main cradle. The " bilge " blocks on the auxiliary cradle are then removed, the arms of the main cradle are swung round to their proper places, and the sliding " bilge " blocks are run in, when the main cradle with the ship resting on it moves down the slip-way, leaving the auxiliary cradle behind ready for receiving the next vessel.