EVOLUTION OF SCREW PROPULSION IN THE UNITED STATES. 57 



shipyards, he strongly recommended building an iron steamer propelled by twin 

 screws as being the most suitable for the service. Acting upon this advice, a con- 

 tract was made with the firm of Betts, Harlan & Hollingsworth, of Wilmington, 

 Delaware, for a vessel of the following description : 



Length, water line, 125 feet. 



Breadth, 23 feet 6 inches. 



Depth of hold, 10 feet. 



Rig, 3 masted, for and aft schooner with bowsprit and standing gaffs. 



Machinery, twin screw consisting of two single engines, 22 by 24-inch cylinders. 



One drop flue boiler. 



Stateroom and berth accommodations for about 150 persons. 



The keel was of 7-16 inch plate. 



Hull plating, \ inch to f inch thick. 



Frames, flat bar iron, 3 inches by f inch, spaced 20 inches, to which the 

 plating was secured by U-shaped clips, or keepers, one foot apart, rivetted to the 

 plates. 



The price of the hull, based on a weight of 94,447 pounds at 9I cents per pound 

 was $9,208.58. 



Price of machinery, $7,650.00. 

 Separate contracts were made for carpenter and joiner work, rigging, painting, 

 etc. The toal cost of the vessel, ready for sea, was about $21,000.00, an itemized 

 bill for which, submitted by the builders, is in the possession of the writer. 



The propellers were 8^ feet in diameter of the "Loper" type, for the use of 

 which the patentee was paid a royalty of $530.00. The increased cost of living seems 

 not to have obtained in the matter of propeller wheels since 1845. 



The vessel was about 7 months in building, was named the "Bangor," and at 

 a builder's trial on the Delaware July 25, 1845, showed a mean speed of 11.56 miles 

 per hour, with steam pressure of 46 pounds. 



She then went on the route between Boston and Bangor, and on her second 

 trip, when entering the Penobscot River, fire was discovered in the cargo, which 

 spread rapidly to the woodwork of the vessel which was entirely destroyed. She 

 was beached as soon as possible after discovery of the fire and no loss of life occurred. 

 The finances of the Company did not survive the wreck, and the boat was floated 

 and rebuilt by other parties and taken South where, under the name of "Scourge," 

 she was used by the Government as a transport in the Mexican War. At the close 

 of that war she was sold in New Orleans after which time all record of her seems to 

 have been lost. 



The President : — If there is no further discussion on this paper, we will pass 

 it, with the usual thanks to Mr. Cramp for the interest he has taken in the subject. 

 The paper "Floating Dry Docks in the United States ; relative value of wood and 

 steel for their construction," by Mr. William T. Donnelly, Member, we will take 

 up now. 



