128 



A TREATISE ON DREDGES AND DREDGING 



deep and serve to strengthen and carry the weight of the upper 

 deckhouses. They also sustain the weight and thrust of the front 

 A frame and furnish the necessary support for the wheel beams at 

 the aft end. The hull is further stiffened by four transverse water- 

 tight steel bulkheads. 



The engines are of the triple-expansion marine type of 500 H.P. 

 The engines and pump as they appear in the engine room are illus- 

 trated in Fig. 37. There are no special features about this engine 



FIG. 39. Dredge "King Edward VII." 



which call for detailed desciiption. It is simply a first-class marine 

 engine without the link motion. The work of driving a centrifugal 

 pump is somewhat analogous to that of driving a screw propeller, 

 and therefore the type of marine engine is well adapted to the pur- 

 pose. There are, of course, many little practical details concerning 

 the manner of attachment of the pump and providing for the special 

 wear and thrust that occur in the pump that are different from 

 marine practice. 



The dredging pump itself is of the centrifugal type, of a pattern 



