TRANSPORTATION OF THE DEBRIS 



197 



The scow (see Fig. 60) is about 62J ft. long and 22 ft. wide; 

 on this is placed a platform 32 ft. long and 22 ft. wide, which is 

 arranged to slide on 8 roller ways inclined at an angle of 1 in 28, 

 transverse to the axis of the boat. Between these ways there are 

 three struts or braces, one in the middle and the others near the 

 ends of the platform. The lower ends of these braces turn on a vertical 

 bolt fixed to the deck of the boat and the upper ends abut against 

 strong blocks fixed to the platform. These three braces are tied 

 together by a rod attached to a lever which by a simple movement 





FIG. 66. Sidewheel Tugboat. 



releases the braces from their blocks and leaves the platform rest- 

 ing free on the rollers. Wooden guides keep the platform to its 

 track. 



The dumping operation is as follows: As soon as the braces are 

 released the platform glides outward on the inclined track by reason 

 of its load. After moving about 3 ft. it is checked by bringing 

 in contact the blocks fastened one to the platform and the other 

 to the deck of the boat. Under the change in the center of gravity 

 the boat assumes the position shown in Fig. 65 B until the deck 

 load is discharged, an operation consuming about 10 seconds. 



