230 THE PROPELLING MACHINERY OF THE U. S. S. LEVIATHAN. 



Lower half casing. — The first four rows at the steam inlet end were badly 

 damaged. 



Top casing. — (a) The first three rows at the, steam inlet end and last row at 

 exhaust end were badly damaged. 



(&) A pocket about i6 inches wide had been cut through seven rows of blades. 



All this blading was refitted, amounting to about lO.ooo blades and packing 

 sections. 



This turbine was closed up on October 4, and on October 20 it had been 

 coupled up to the low-pressure ahead and both revolved in ahead and astern di- 

 rections satisfactorily. 



High-Pressure Astern {Starboard Inboard). — When this casing was opened it 

 was sd£n that very considerable repairs would be necessary to make this turbine 

 work successfully: — 



(a) The three rows of the impulse wheel buckets of rotor were badly damaged. 



(b) The dummy cylinder had been removed, and the dummy piston showed 

 clearly that it had been rubbing in contact with the dummy cylinder. Lumps of 

 metal had fused on to the piston surface and it was badly distorted. 



(c) The four last rows of rotor and casing blades were damaged and re- 

 quired renewal, together with a pocket 18 inches wide which had been cut through 

 six rows of rotor blades and six rows of casing blades in the lower half. 



(d) The cast-iron casing was also found to have large cracks or fractures, 

 which had undoubtedly been caused by the revolving dummy piston of rotor coming 

 in contact with the dummy cylinder, which eventually fractured into a number of 

 pieces. These pieces apparently jammed whilst the rotor was revolving, and finally 

 resulted in fractures developing in the main casing" walls. 



Top casing. — (a) On the interior surfaces there were four fractures in all, three 

 being in the nozzle openings. Fig. 16, Plate 103, shows the approximate position of 

 the damage in the casing, and also the extent of the fractures. 



(&) Externally, there were small cracks under the nozzle openings, in line with 

 the internal fractures. 



Fig. 16A is a section across the inlet steam belt of the top casing and looking 

 forward. 



Fig. 16B is a hand sketch of a cross-section, in way of the nozzle openings. 



Lower casing. — In this half of the casing the damage was much greater, and 

 the question of making satisfactory repairs became a very serious matter. 



(a) There were eleven internal fractures or cracks, and Figs. 17A and 17B, 

 Plate 103, give the approximate location of the damage and also show the extent 

 of each fracture. 



(b) Fractures i to 4 are somewhat similar to the three in the upper half; they 

 extend from the facing to which the dummy cylinder is bolted right over to the 

 dished end wall of the casing. 



(c) Fractures 5 to 8 occurred in the wall which supports the end of the dummy 

 cylinder, and are similar to fracture 4 of the upper half casing. 



