SLIPWAYS. 



323 



cradle. Alongside the upper portion of the main rails, and 

 parallel with them, is placed a second set of ways, upon which 

 the auxiliary cradle travels. The slope of these rails is greater 

 than that of the main ways, in order that when a vessel has been 

 hauled up until it is over the auxiliary cradle, and new bilge- 

 blocks have been fitted, the hauling-up of the two cradles 



FIG. 320. End View of Cradles yoftetfrom top of Slipway. 



simultaneously may cause the vessel to be gradually lifted up by 

 the auxiliary cradle from the increased inclination of its rails ; so 

 leaving the main cradle free to be lowered down the ways for 

 receiving a second vessel after the transverse arms have been 

 swung round into a longitudinal position. 



When the ship is to be launched, the main cradle, with its 



FIG. 321. End view. 



arms, swings round, and resting on the side ribs, is hauled up 

 under the vessel, the arms are then put into position and the 

 bilge-blocks run in, and the main and auxiliary cradles 

 simultaneously lowered down the ways. The greater slope 

 of the rails of the auxiliary cradle causes the vessel gradually 

 to approach and seat itself on the resting-blocks of the 

 main cradle, and, the bilge-blocks on the auxiliary cradle being 



