DESCRIPTIONS OF CLAMSHELL DREDGES 179 



The hull was made entirely of wood, 120 ft. long, 40 ft. beam, and 

 12 ft. 6 in. deep. The length given does not include a moulded 

 bow and stern of falsework, which were added to make the dredge 

 tow easier, and which increased the total length to 160 ft. The 

 A frame was 50 ft. high above deck and the boom 65 ft. long. There 

 was a single spud at each end of the hull, but these spuds instead 

 of extending to the bottom, acted simply as attachments for the 

 anchor ropes by which the machine was really held in position. 

 The usual manner of anchoring dredges working in water too deep 

 for spuds is to run the anchor line from the level of the deck. With 

 a beam wind and heavy sea several anchors are usually required 

 to hold the dredge in place, and these interfere seriously with the 

 free handling of scows and tugs alongside. It was therefore desired 

 to remedy this fault in constructing the present machine. 



The dredge was provided on each side with a spud, 3 ft. 

 square, which extended 25 or 30 ft. below water. At the bottom 

 of each spud there were three sheaves, two fixed across the spud 

 and one fore and aft. On the deck, close to the spud, were located 

 three other sheaves. The anchor lines passed from the drums over 

 the sheaves on deck, down along the sides of the spuds, through 

 guides cut in the spud wells, and under the sheaves in the bottom 

 of the spud out to the anchors, some 300 ft. away. This arrange- 

 ment held the dredge with anchors in six different directions, the 

 line of which were 25 ft. under water, giving free access to scows 

 and the largest tugs to approach the dredge from all directions. 

 In actual operation the center bow anchor was not used, as it was 

 not required, and its removal did not interfere with the free operation 

 of the bucket. The remaining five anchors have proved their ability 

 to hold the dredge on the line of the work with a strong beam 

 wind and heavy sea. The dredge moved backward along the line 

 of the cut, the movement being accomplished by Raiding in on the 

 center stern anchor line. A patent for this form of anchor attach- 

 ment was secured by the Osgood Dredge Co. 



Turning now to the operating machinery, the main engine, 

 placed amidship, operated the dredge bucket. This was an 18 X 

 2-4-in. double-cylinder engine, with Stephenson reversing gear, and 

 was compound geared to two 6O-in. drums, with gear faces 

 12 ft. in diameter and double frictions of the V type, the male V 

 was of iron and the female lined with lignum vitae. The male 

 Y was hollow, and to keep the friction faces cool, water was 



