WESTERN RIVER STEAMERS. 61 



side at New Orleans by triple and compound tugs and is towed down from Pitts- 

 burgh by compound condensing towboats. Since for so many years the ocean and 

 lake power has been developed with from one-third to one- fourth this consumption 

 of fuel, we may readily look to our engine rooms for some of the losses that are 

 annually augmented by labor charges and loss of time. 



The satisfactory performance of the tunnel propeller towboat A. M. Scott 

 on the Missouri River has been the cause of the U. S. Engineer Department order 

 ing from Mr. Ward a sister vessel to replace the stern-wheeler Mississippi. The A. 

 M. Scott has two 6o-inch propellers, driven by triple-expansion surface-condensing 

 engines. The four tunnel boats now in use on the Missouri River were not designed 

 for service on that stream, which, in low water, is more nearly a flowing roadway. 

 There are always details of construction that make a craft more adapted to certain 

 localities. The tunnel steamer Chester was designed as a triple screw, with wing 

 triple engines exhausting into a non-reversible low-pressure turbine, which should 

 add about 400 indicated horse-power to this plant, but the boat has seen service for 

 three seasons as a twin-screw packet boat, and the center propeller and the more 

 economical turbine have not been installed. This installation will add about one- 

 third more speed to the boat, at absolutely no additional fuel expense. 



We found that, in shallow waters, much more power is required by any type of 

 boat. A constant for this increase of power is not obtainable as in deep-water 

 practice, owing to the constantly changing conditions of current and depth of water. 

 On any paddle-wheel boat, perceptible and sometimes vastly apparent losses of 

 power and speed occur when running into shallower water, but no tests that are 

 available have been made. The stern-wheel steamer Advance, drawing 36 inches of 

 water and pushing a barge about her own size drawing 48 inches, showed the fol- 

 lowing losses, during a recent test on the Missouri River. Soundings were taken at 

 the engine-room door, and not on the head of the tow, a difference of about 200 

 feet. We find practically no loss of time or power with the tunnel boats, and no 

 squatting or wallowing in extremely shallow water with 6 inches to one foot of 

 water under the hulls. 



