196 A TREATISE ON DREDGES AND DREDGINd 



merits. These hopper steamers being very expensive, only govern- 

 ments and public corporations can afford to invest an enormous 

 capital for the sole purpose of obtaining a better means of trans- 

 portation. On account of the almost prohibitive cost of the steam 

 hoppers, manufacturers have devised schemes to extend their utility. 

 The propelling machines have been increased in power so that the 

 steamer could be used as a tugboat; and in many cases with good 

 weather prevailing have been used, even with a full cargo, to tow a 

 line of dumping scows. Steam hoppers have been also supplied with 

 fire-extinguishing pumps so as to be utilized as a fireboat. In such 

 cases the steam hopper performs a double duty. Steam hoppers have 



B 



FIG. 65. Dumping Scow with Sliding Platform. 



also been supplied with a centrifugal pump and a suction tube, and 

 thus have been converted into a sea-going hopper hydraulic dredge of 

 small capacity, convenient for cleaning the quays and piers around 

 the harbor. Finally the steam hoppers have been used for life- 

 saving purposes and for helping vessels that are in distress. Thus 

 the steam hoppers "San Demetrio" and "San Caledonio" built by 

 H. Satre & Co. and used in the improvements of the harbor of 

 Santander, Spain, on many occasions during the great storms pre- 

 vailing in that locality have put to sea and helped numerous fishing 

 smacks and steamboats. 



Another type of dumping scow built on an entirely different 

 principle was used for dumping rocks in the dyke construction 

 at Newburyport, Mass. 



