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BoD kota are sister ships in all respects except the main propelling engines, the Delaware being fitted wth the reciprocating type of engine and the North Dakota with the Curtis marine steam turbine. "Tf a fair comparison between the different types of engines installed on the two sh'ps is to be made it should show the results from the steam consumed by the engines, and all other factors and influences should © be arranged so this resuit can be obtained. In other words, if the re- ciprocating engines on the Delaware use less steam per hour than the tur- bines on the North Dakota when the ships are run at the same speed then the economy of the Delaware's pro- pelling machinery is better than that of the North Dakota. Th's result is not indicated in the same way by. a comparison of the coal consump- tion, because other factors are then introduced which do not confine the comparison to the engines only, "This comparison cannot be made on a basis of the amount of steam per horsepower, because the horse- power for a given speed is much less on the Delaware than on the North Dakota on account' of the better effi- ciency' of the Delaware's propellers, made possible by the use of recipro- cating engines. The comparison must, therefore, be made on a basis of the amount of steam consumed per hour at a given-speed, and for this reason we have tabulated the amount of steam in tons used by all machinery in operation, per hour, for the differ- ent speeds. A comparison of these figures with those obtained from the trials of the North Dakota show a less consumption of steam for the Delaware at all speeds than for the North Dakota, this difference being about 35 per cent at twelve knots." _ The following comparative table is supplied by the Bureau of Steam En- gineering, and shows the comparative steam performances of both ships re- duced to a common speed basis. Ai the cruising speeds the difference be- tween the two ships is not only marked but striking: A comparison of the powers of the two- ships at practically the § same speed is of interest. At 21.6 knots the shaft horsepower of the North Dakota is given'as 31,400 and of the Delaware at 21.56 knots the indicated horsepower is stated as 28,578. Al- lowing 88 per 'cent mechanical effi- ciency for the engines on the Dela- ware, or in Other words, 12 per cent for friction losses, the shaft horse- power will be roughly 25,150 as com- pared with the 31,400 of the North THE Marine REVIEW December, 1909 : DELAWARE. Wat eee He Pe hour, main en-] 12 knots. 19 knots. 21 knots speed. fies ty tea, aati - a i setae eee sae i 15.48 lbs. 1227<1bs. 12.9 lbs. water. WwW t Pe peredet bP; per 12.24 knots. 19.225 knots. 21.563 knots speed. ater per H. P. per hour, all parece Ta hoes ie ie ha ae Total ter rc all. purpesesic. 3 oe. 12.24 knots. 19.225 knots. 21.563 knots speed. eee j 83,463 Ibs. 250,549 Ibs. 422,931 Ibs. water. Total wat2r per hour, for main engines. 12 knots. 19 knots. 21 knots speed. Only ss : Se DRA eae Sees PN see ' 55,000 lbs. 205,000 Ibs. 312,000 Ibs. water. NORTH DAKOTA. Water per S. H. P. per hour, train fur-{ 12 krots. 19 Ixnots. 21 knots speed. PICS Cathy rt nite Rican gies ec awn aa ones § 20.6 Ibs, 14.25 lbs. 13.8 Ibs. water. "Water per. SiH. "Ps per hour, maia tur-] 912.1 knets. 19.245 knots. 21.64 knots speed. bines+ and sengines: auxiliariés..:...0.. << §. 423,94 Ibs: 15.92 lbs. 14,408 Ibs, water. Total water per hour, main turbines andl 12.066 knots. 19.245 knots. 21.64 knots speed. PONOTM ES ra IIATICS 6 Gi esas be a eee eee § 90,984 Ibs. 266,761.1 lbs. 450,965 lbs. water. Total water per hour for man turlines( 12 knots. 19 knots. 21 knots speed. GTdYe Mar eis ee gee Get MA ine oe § 76,000 lbs. 23,800 lbs. 349,000 lbs. water. Dakota, so that for power actually delivered: to the propellers the effi- ciency of the latter is practically 25 per cent higher in the 'case of the Delaware than of the North Dakota. Th's difference in propeller efficiency is observable to a greater or less ex- tent between all turbine and recipro- cating engine driven ships, though sel- dem in so marked a degree. NEW STERN WHEEL TOW BOAT. Joseph Supple, shipbuilder, land, Ore. 'has taken a contract for the construction of a wooden stern wheel towing boat for the Willamette & Columbia River Towing Co. The machinery, irons and chains from an old hull will 'be used in the new boat. The complete boat will represent a value approximating $34,000. dhe hillis. 160 ft. long, 33 ft. beam with 7 wt. depth of hold. The irames are double, flitch sawed fir, 4. in. Suiare set. 22:1. on. centers... Che propelling machinery ts set on oak foundations with steel I beams used in place of engine timbers. Oak lum- ber is used genefously in all places of special strain or wear. This makes one- of the staunchest hulls on the Columbia river. The engine cylinders are 19 in. in diameter by 84 in. stroke, stern wheel type. The boiler is of the fire box type, burning crude oil for fuel. The hull is modeled on fair- ly fine lines forward so that the boat running will make good time when light. General Shipbuilding Conditions at Portland. Commenting on general business conditions; at Portland, Ore, Mr. Sup- ple says: "Aside from this contract and a regular run of repairs on small oratt-iand work in the yard is scarce for this season of the year. barges, Port-. I hope that business will pick up alter' the 'first' ol tite "year." © There will always be some demand for wooden boats and always some repairs to be made. Thus, while there is a great tendency toward steel consiruc- tion, the days of the builders of wooden craft are not yet numbered." CATALOG OF WATER TUBE BOILERS. An attractive catalog describing a new type of 'water tube boiler has been issued by the Ballin Water Tube Boiler: Co, of -sPortland, Ores The catalog = consists. 6. 29. 5 by 37 in pages, with a large number of draw- ings and photographs showing in de- tail the 'construction of the Ballin water tube boiler. The first boiler of this type was installed in the high speed passenger steamer H. B. Ken- nedy, where it has given continuous service under trying conditions. for over seven months. The 'boiler. was completely described in THe Marine Review, Oct. 1909. The catalog con- tains considerable engineering data, tables and formulae bearing on the proper selection of boilers for marine service. The new tug M. P. Howlett, launch- ed at Wilmington, Del., last week for M. P. Howlett of. Philadelphia, has been towed to New York for her engines and boilers which will be put in place by the Waters, Gloderslee Calver Co, at Staten Island. The Boston-Galveston steamship service will be inaugurated on Dec. 1. The service will be given jointly by the Mallory and Clyde lines and there wilf tbe weekly Four vessels, two from each line, will con- stitute the fleet. sailings.