THE PROPELLING MACHINERY OF THE U. S. S. LEVIATHAN. 233 



the only provision being a small drain cock and pipe led from the stop-valve on each 

 boiler down the boiler front to the bilges. 



The boiler installation is very similar to that of the Imperator, and a full de- 

 scription, with illustrations, was published in Engineering, June 12, 1914. 



General Overhaul. — Whilst the repairs to the main turbines were in progress, 

 the auxiliary machinery was overhauled thoroughly; the four main condensers were 

 water-tested, new tubes fitted to the auxiliary condensers, and new packing was 

 fitted to the gland bushes of all reciprocating engines and steam cylinders of the 

 auxiliaries. 



The main steam lines, as well as the auxiliary steam lines, were fitted with 

 proper drains and traps. 



The forced lubrication system, including oil coolers, oil drain tanks and piping, 

 was thoroughly cleaned. 



The line shaft bearings were removed and freed of all grit and dirt, and the 

 stern tube glands repacked. 



DOCK TRIALS. 



The preliminary steam trials of the turbines began early in November and 

 were made with the turbines uncoupled from the line shafting. 



All the turbines were driven up to full-speed revolutions, namely, 180 per min- 

 ute, in ahead and astern directions. 



A slight hitch occurred with the starboard high-pressure astern. The regula- 

 tor valve jammed open, resulting in the turbine gaining momentum rapidly. On 

 shutting the by-pass valve the steam pressure on top of the piston forced this down 

 with a bang, and on opening out the valve it was found that the piston valve was 

 fractured right around the metal which supports the valve stem. It is useless to 

 speculate just when this fracture took place, but it is not improbable that it may 

 explain why this turbine was damaged much more than the other units. 



SEA TRIALS. 



The vessel left New York Harbor for extended trials on Saturday, Novem- 

 ber 17, and returned on Thanksgiving Day, November 29. During that time vari- 

 ous trials were carried out at cruising speeds, and records of the coal consumed 

 were made. 



A short trial was made at full speed, the average revolutions of the four 

 shafts being 171 per minute, corresponding to a speed of about 22.50 knots. No 

 torsion meters were in use, but the estimated shaft horse-power amounted to about 

 65,000. 



The main turbines worked splendidly throughout the whole series of the trials, 

 and absolutely no adjustments had to be made. The engines maneuvered splen- 

 didly, and the astern turbines did good work. 



Minor adjustments were made to some of the auxiliary machinery and to the 

 steering gear, but, taking everything into account, the performance of the machin- 

 ery was most satisfactory. 



