TOM SAWYER Twin Screw Diesel, River Towboat screw tunnel type diesel engine propelled towboat recently com- pleted under contract by the Mid- land Barge Co., Midland, Pa. for the Inland Waterways Corp. for service on the upper Mississippi river and its tributaries. This towboat was designed by the engineering depart- ment of the Inland Waterways Corp., under the direction of Major Gen- eral T. Q. Ashburn. : Trials were conducted on the Ohio river near Midland, Pa., during the middle of May when thorough tests of all machinery and the maneuver- ability of the boat were proven sat- isfactory to the owner’s representa- tives. The accompanying photograph was taken just previous to its trip down the Ohio to be delivered to its owner at Cairo, Ill. The towboat is built to the fol- lowing dimensions: Length, mold- ed, 160 feet; breadth, molded, 40 feet 0 inches; depth at sides, 8 feet 0 inches; crown, 6 inches. The bow is modeled with sponson; and the stern is of tunnel type for propellers. The sheer forward is 14 inches, and the sheer aft is nil. The draft is 4 feet 6 inches fully stored including 50 tons of diesel fuel oil and 30 tons of fresh water. Classification is with the Ameri- ean Bureau of Shipping and the ves- sel was constructed under a special survey of the bureau. The hull is of steel construction throughout. There are six transverse bulkheads extending from side to side of shell. A watertight center line bulkhead extends from forward end to after end of boat except in way of sunken deck of engine room through which a watertight keelson is constructed. In way of the engine room sunken deck, longitudinal strength is ob- tained through the heavy guard decks, wing bulkheads, ship sides, Te TOM SAWYER is a twin 16 and bottom plating, which form box sections five feet wide by eight feet deep on port and starboard sides of the boat. Heavy engine foundation girders extend through the bulkheads at the forward and after ends of the sunk- en deck, the inboard girders con- necting to longitudinal trusses are spaced midway between the wing and center line bulkheads. The sunken deck which is 30 feet by 26 feet long extends to the wing bulk- heads and consists of transverse floors about 2 feet deep covered with removable sections of %-inch alu- minum alloy plates. Constructed of 3/16-inch and %4%- inch plating the main deck house is reinforced by suitable angle iron stiffeners and divided into seven compartments by steel bulkheads. The upper deck house is construct- ed of long leaf yellow pine studding and tongue and groove cypress boards and is lined inside with 4- inch pressed board. The hurricane deck is constructed of 2 x 6-inch deck beams and planked with 1% x 5%-inch tongue and groove yellow pine. The entire deck outside of pilot house is covered with No. 4 eanvas thoroughly filled with lead paint. The pilot house is construct- ed of long leaf yellow pine and lined with pressed board. Skylights over the engine room and galley, walkways and_ (floor plates in engine room are all alu- minum alloy to decrease weight, as light draft is very essential on the upper Mississippi and its tribu- taries. Living quarters consist of 12 rooms, 6 baths, 7 toilets, 14 lava- tories, 2 mess rooms, 1 pantry, 1 double refrigerator, and one galley, arranged for accommodating a nor- mal crew of 18, with 5 spare berths. MARINE REVIEwW—July, 1933 Two rooms with baths separate the galley personnel from the rest of the crew. Diesel Propelling Machinery The vessel is propelled by two vertical eight-cylinder four-cycle single acting mechanical injection direct reversing marine diesel en- gines of 12%-inch bore and 22-inch stroke, built by McIntosh & Sey- mour Corp., Auburn, N. Y., having a normal rating of 590 brake horse- power at 300 revolutions per min- ute and 675 brake horsepower at 330 revolutions per minute making a total of 1350 brake horsepower at overload rating. This power can be maintained for several hours with- cut imposing undue strains on the engines. Each engine is fitted with fly wheel, built-in thrust bearing, two stage air compressor gear type lu- bricating oil circulating pump, recip- rocating jacket water circulating pump, attached speed governor, fuel transfer and booster pumps, fuel in- jection pumps. indicator motions, hand turning device, air intercooler and after cooler, air automatic un- loading valve, and air pressure re- ducing valve. Each Kingsbury thrust bearing is rated at 37,000 pounds. Each air compressor has capacity to supply air at 350 pounds for 6 starts of each engine per hour. Each lubri- cating oil circulating pump has ¢ca- pacity to supply 100 gallons per minute, and each jacket water pump circulates a sufficient quantity for proper cooling of engine. In common with the usual prac- tice on the rivers, these boats are relatively wide, and the engines are mounted at some distance apart. The maneuvering gear, however, is arranged through shafts and chains Tom Sawyer— twin screw, tun- nel stern, diesel drive, river towboat, com- pleted May, 1933, by Mid- land Barge Co., Midland, Pa, for Inland Wa- terways Oorp. Speed 8 statute miles per hour. Sister boat Huck Finn to be completed July 16