Engineering Wonders of the World
Volume I

THE EQUIPMENT OF A MODERN SHIPYARD. 73 trations as representing the latest methods of ship construction. The stem bar and stern frame, which are usually of forged iron or cast steel, must be got into position on the build- Stem Bar and K ,, , . , _ mg berth at an early stage m Stern Frame. ° J ° the vessel s construction. The stem bar is at the extreme fore end of the vessel, and extends upwards from the termina- tion of the keel plate to the highest deck. To the stem bar the shell plating on both sides of the ship is attached. The stern frame, or, as it is some- times called, the stern post, is at the extreme after Fig. 12.—the “ Lusitania’s ” stern frame and SUPPORTS FOR THE INNER PROPELLER SHAFTS. The immense size of the castings forming the stern frame and propeller shaft supports, which weighed nearly 100 tons, will be appreciated on comparing them with the 6-foot driving wheel which the man is holding up in the position that was afterwards occupied by the rudder. end of the vessel. As in the case of the stem bar, the plating of both sides of the vessel is con- nected to the stern frame. In the stern frame for a screw steamer there must be a support for the shaft passing from the engines to the pro- peller ; or, in the case of a twin-screw vessel,two such supports must be provided, one for the port and the other for the starboard propeller shaft. Connections for the rudder must also be forged or cast on the stern frame, the rudder usually being added to the vessel at a later stage. A view of the cast-steel stern frame of the Lusitania, as it appeared in the shop of the makers, is given in Fig. 12. The supports for the two inner propeller shafts (the vessel was fitted with four propellers) may be seen to the right of the picture, while nearer the left the connection for the rudder is shown. As the Lusitania and Mauretania were designed to act as armed cruisers or scouts in time of war, the Fig. 13.—PORTABLE RIVETERS FOR GIRDERS. rudder of each vessel had to be fitted well below the water-line to protect it against gun fire, and consequently the design of the stern frame was somewhat different from that usu- ally adopted in a merchant steamer. The framing of the ship being well in hand, the outside or shell plating is commenced, and drawings are supplied for this purpose to