24 METHOD OF CONSTRUCTION OF CONCRETE SHIPS. 



engine-room. The installation of the oil piping is similar to the installation in a 

 steel ship of similar type. In Fig. 2, Plate 5, the holds for the oil cargo are marked 

 "Cargo Oil." Immediately forward and aft of these compartments are small holds 

 for dry cargo. To serve these holds each of the two masts is provided with one 

 5-ton boom. 



There is very little to be said in regard to the fitting out of the crews' quarters, 

 for they differ in no way from the quarters on any of the other Emergency Fleet 

 ships. The exterior walls of the deck erections on all the ships are of concrete ex- 

 cept the poops on the 7,500 D. W. T. ships, which are of wood bolted to the con- 

 crete by through bolts. None of the crew are quartered in the forecastle. The 

 eight seamen have two large staterooms in the poop, and the rest of the ship's com- 

 pany are quartered in the bridge-house. 



TRIAL TRIPS. 



After the outfitting and installation of machinery has been completed, it is 

 customary to subject the ship to two tests before it is accepted as ready for service. 

 The first test is made while the ship is tied at the wharf and is known as the "Dock 

 Trial." At this time the boilers are fired and the engines run at full speed for a time 

 long enough to satisfy the trial board as to their proper performance, and the aux- 

 iliary engines are tested. 



After the dock test the defects discovered are remedied and the second and 

 final test made. In this test the ship is taken to sea and made to perform all the 

 evolutions to be encountered in actual service. 



At the time of writing, only the 3,000 and 3,500-ton D. W. experimental con- 

 crete ships have made their trial trips. 



On the trial trip of the Polias (3,500-ton D. W.) the log shows that she was 

 run for six hours at full speed, averaging 10.5 nautical miles per hour. Over a 7- 

 mile stretch of this course, the speed was figured at 1 1.4 nautical miles per hour. At 

 this speed her engines were making 93 revolutions per minute and indicated 1,364^/3 

 horse-power. This part of the trial is run to test a ship's propulsive equipment 

 and determine if she makes her guaranteed speed, which in the case of the Polias is 

 10.5 nautical miles per hour. 



After the speed run had been made, the maneuvering powers were tested. 

 While the ship was running at full speed she was steered through a figure 8. The 

 log shows that the complete turn on the port wheel was made in 6 minutes 25 sec- 

 onds and on the starboard wheel in six minutes. The wheel was thrown from hard 

 over to hard over in twelve seconds, which is a very good average for a ship of 

 this size. 



Next the auxiliaries were tested. The dynamo was loaded to its maximum, the 

 ice machine tried out, feed pumps testeid, and the temperature of the feed water 

 and stack gases taken. Both anchors were let go and hove up in fifteen minutes, and 

 the hand-steering gear used to steer the ship ; finally, the engines are reversed and 



