Maritime Commission Design C1-B

Descriptions for MC-94 to 98 (Western Pipe & Steel built)

General

The first of five C-l-B design full scantling cargo motorships which are being built by the Western Pipe & Steel Company, San Francisco, Cal., for the United States Lines, New York, under a contract placed by the Maritime Commission, was delivered to the owners on April 11. The contract for the construction of the vessel was awarded in October 1939, her keel was laid on February 5, 1940, and the vessel was launched on August 8, 1940, when she was christened American Manufacturer by Mrs. K. D. Dawson. The vessel will be used in the United States Lines' service to the Orient and Australasia as a unit in the American Pioneer Line's fleet until after the war when with her sister ships she will go into the transatlantic service. Her sister ships under construction by the Western Pipe & Steel Company are the American Leader, launched on October 8, 1940; American Builder, launched on December 17, 1940; American Press, launched on March 11, 1941, and American Packer, scheduled for launching on May 22, 1941. The detailed plans of these vessels were prepared for the Western Pipe & Steel Company by George G. Sharp, naval architect, New York. The American Manufacturer is of the flush deck full scantling type with a raked stem and cruiser stern, and was built to the American Bureau of Shipping's highest class. Two complete steel decks, the main and second decks, are fitted and a third deck is fitted below the second deck extending from the stem to the forward machinery space bulkhead. Abaft the machinery space a flat is fitted below the second deck at the level of the top of the shaft tunnel. The steel was supplied by the Columbia, Bethlehem and Republic Steel Companies, the castings by Columbia, Monach and Acme and the forg-ings by Bethlehem. The hull is of all-welded construction. The main deck has sheer and a camber of 14 inches in 60 feet. The second deck has sheer but no camber and the third deck is parallel to the second deck without camber. The double bottom extends from the forward collision bulkhead to the after collision bulkhead. Deep tanks are provided for 702 tons of liquid cargo. The hull is subdivided by seven transverse bulkheads, all watertight to the main deck. Five cargo holds are provided, three forward and two aft of the machinery space. Cargo is handled through five hatches, one for each hold, no side ports being fitted. The hatches on the main deck are fitted with steel covers and on the lower decks with wood covers. Masts are fitted on the centerline of the vessel between hatches Nos. 1 and 2, 2 and 3, and 4 and 5, to which cargo booms are rigged. The masts also serve as exhaust or supply ventilators to the cargo holds. Two king posts, one port and one starboard, are fitted at both the forward and after ends of the deck house. These king posts carry cargo booms and also serve as ventilators for Nos. 3 and 4 holds. Hatches Nos. 1 and 5 are provided with two 5-ton booms and two winches each. Nos. 2, 3 and 4 hatches are provided with four 5-ton booms and four winches each. Each of the sixteen 5-ton booms have an outreach of 14 feet over the maximum beam of the vessel. All of the booms are stepped above the resistor houses in order to clear deck lumber loads. A 30-ton booms is stepped on top of the resistor house on the centerline of the vessel forward of No. 2 hatch. The cargo winches, supplied by the American Hoist and Derrick Company, are driven by 50-horsepower General Electric motors. Two of the winches are of the double-gear type for handling 30-ton loads. The remaining fourteen winches are of the single-gear type. All of the winches are installed on the main deck. The single-gear winches have a capacity of 6720 pounds at 220 feet per minute and a normal load of 3000 pounds at 350 feet per minute. The anchors and anchor chains were supplied by the Baldt Anchor, Chain & Forge Corporation. The windlass, supplied by the Markey Machinery Company, is of the horizontal spur-geared type driven by a 50-horsepower General Electric motor. A single Markey capstan is installed aft for warping and mooring. The steering gear, supplied by Lidgerwood, is of the electro-hydraulic double-ram type, controlled by a telemotor transmission and gyro-pilot system. The living quarters are all in a deck house amidships. As shown on the general arrangement plans the crew's quarters, messrooms, galley, hospital and ship's stores are on the main deck, while the officers' quarters, accommodations for eight passengers, combined dining room and lounge and the pantry are on the cabin deck. The captain's office and stateroom and the chief mate's stateroom are on the bridge deck with the wheel house, chart room, radio room, gyro room, fan room and the emergency generator room. Mechanical ventilation and heating is provided for all living and working spaces. The cargo and living spaces, radio room, gyro room, laundry, linen lockers and dry storerooms are provided with a mechanical supply system ; the hospital, galley, pantries, and emergency generator room with both supply and exhaust, and the toilets and radio battery room with exhaust only. The ventilating fans were supplied by the B. F. Sturtevant Company and the radiators by Modine. In the accommodations the plumbing fixtures were furnished by the American Radiator & Standard Sanitary Corporation, the lighting fixtures by the Dayton Manufacturing Company, the general alarm and annunciator systems by the Tourney Electric & Engineering Company and the telephones by the American Automatic Electric Company. The vessel is thoroughly protected against fire hazard not only because it is built throughout of incombustible or fire-resisting materials but also because complete fire-detecting and fire-extinguishing equipment has been installed by Walter Kidde & Company. The Rich "smoke-pipe" fire-detecting system is installed in all cargo spaces, the paint locker, carpenter shop, dry storeroom and bosun's storerooms. A complete C02 extinguishing system protects the cargo spaces, service spaces and machinery space. This is supplemented by the usual water fire-extinguishing system served by the fire pump and the fire and sanitary pump, and also by the required number of portable fire-extinguishers. The lifesaving equipment includes two 28-foot Welin lifeboats, with a capacity of 60 persons each, stowed under Welin mechanical davits on the bridge deck. Very complete navigating equipment is installed. In the wheel house forward on the bridge deck there is a magnetic steering compass, the steering wheel, a Sperry gyro-pilot and Sperry gyro-repeater, a Submarine Signal Company fathometer and a Tourney engine-room telegraph. On the top of the wheel house there is a standard magnetic compass, a Sperry gyro-repeater, a radio direction finder loop, a steering stand, an engine-room telegraph and an 18-inch searchlight. At the after end of the main deck there is also a steering station with a steering wheel and gyro-repeater. The gyro-compass is located in the gyro room aft of the wheel house. A complete ship's radio communication system, supplied by the Radio Corporation of America, is installed.

Propelling Machinery

Propulsion of the vessel is by a 4-bladed solid manganese bronze propeller, with a diameter of about 18 feet 6 inches and airfoil-section blades, supplied by the Doran Company of Seattle, driven by two Busch-Sulzer two-cycle, trunk-piston Diesel engines through Westinghouse electro-magnetic couplings and Farrel-Birmingham reduction gears. The Busch-Sulzer main engines each have seven cylinders, 20 1/2 inches diameter and 27 1/2 inches stroke, and the two engines develop 4150 shaft horsepower when turning at 233 revolutions per minute for normal continuous duty. At this speed the propeller turns at 90 revolutions per minute, which gives the Vessel a speed of 14 knots. The engines are duplicates of those installed on the M. S. Mormacpenn, a detailed description of which was published in our March 1940 issue, except for the fuel pumps. The arrangement of the machinery is shown in the plans of the machinery space, reproduced on page 69. Power is transmitted from the engines to the gears through Westinghouse electro-magnetic couplings, which act as a cushion preventing pulsations of the engine torque from reaching the gears and also as disconnecting clutches by which the engines can be connected to or disconnected from the propeller shaft instantly. The savings in machinery weight and space of this installation as compared with a direct-connected engine of equivalent horsepower and turning the propeller at the designed speed are too obvious to require comment. In addition, the Farrel-Birmingham reduction gear increases the flexibility of the drive by permitting the twin propulsion units to drive a single shaft and also by permitting either main engine to be shut down for inspection or adjustment at sea while the ship continues on its course at reduced speed. In order to provide steam for heating and auxiliary use, a combination waste-heat and direct-fired boiler, manufactured by the Foster Wheeler Corporation, is installed on a grating just aft of, and above, the main engines. The unit consists of a single steel casing and single steam drum, but the heating portion is divided into three separate sections. As there are two engines, the boiler is fitted with two similar heating sections, each of which receives the exhaust gases from one engine. The gases pass upward over the heating surface and generate 1330 pounds of steam per hour at 50 pounds per square inch pressure. The third section of the boiler is heated by direct firing from an oil burner fitted to a refractory-lined furnace, producing 5660 pounds of steam per hour. There is material difference between the waste-heat boiler sections and the direct-fired boiler section, because of the difference in temperature of the gases and the rate at which steam is generated. The waste-heat sections are fitted with horizontal heat-absorbing elements built of 2-inch seamless steel tubing, upon which are shrunk a series of cast-iron gilled rings, having an out- side diameter of 4 4/8 inches, thus giving about six times the heat-absorbing surface of the bare tubing. The castings are 6 or 8 inches long and fitted with male and female joints at the ends, in order to prevent any contact between the sulphur-bearing flue gases, or moisture from sweating, as the steel tubes would rapidly be corroded by either. Cast iron, on the other hand, is highly resistant to oxydation and deterioration from weak sulphuric acid. Thus, the elements have the strength of steel, the corrosion resistance of cast iron, and a great area for the absorption of heat at low temperatures. The elements are expanded into an inlet header at the bottom and connected in parallel series by bolted return bends up to the top row, connections from which are expanded into the steam drum. These elements are arranged horizontally in the gas passage, are secured to a fixed sheet at the end below the steam drum, but are free to expand at the other end. thus eliminating the imposition of any stresses upon the joints. All tube joints are immediately accessible for inspection or tightening by the removal of quick opening access doors, and are out of the gas passage. The oil-fired section is of orthodox, cross drum, forged steel sectional header boiler design, arranged for a straight through path of gases, no baffling being used. The unit is compact, supported upon a heavy steel frame, and heavily insulated to assure high efficiency. Experience with waste-heat boiler construction has dictated unusual requirements for stiffness to offset pulsations created by the engine exhaust. In operation, the steam generated by heat recovered from the exhaust of the main engines at full load is ample for the ship's requirements. At low engine load, or while in port, the oil burner is fired as necessary to make up any deficiency in steam generation. Simplicity of operation is a characteristic of the design and surprising reliability has been experienced with such waste-heat units in the last ten years. The sister ships of the American Manufacturer' will carry similar steam-generating units. Refrigeration of the ship's stores is by a Carrier Freon motor-driven unit located at the upper level in the engine room, port side. In addition to cooling the ship's stores this unit also provides 150 pounds of ice per day from an ice-making machine. The pantry has a self-contained refrigerator. Electricity for lighting and power purposes is supplied by two Diesel-driven 250-kilowatt General Electric compound-wound three-wire 120/240-volt direct-current generators installed on the starboard side of the engine room. The main generator engines are of the Atlas Imperial type mounted on Kortund steel spring vibro-isolators to eliminate vibration. The main switchboard, supplied by General Electric, is located on the flat above the generators. For supplying current to the emergency circuits a 10-kilowatt 120-voJt direct-current compound-wound General Electric generator is installed on the bridge deck. This unit is driven by a Buda Diesel engine. The emergency circuits are controlled from a General Electric emergency switchboard located in the emergency room. Exide storage batteries are provided for starting the emergency Diesel engine and for supplying current to the interior communication system. The motors for driving the various engine-room auxiliaries were supplied by the General Electric Company. The auxiliaries include the following: Three motor-driven Ingersoll-Rand air compressors. Two of these are main units, designed to deliver 100 cubic feet ot free dry air per minute when compressing the air to 500 pounds per square inch. The third unit is a make-up or emergency compressor capable of delivering 10 cubic feet of free air per minute when compressing to 500 pounds per square inch. Two De Laval fuel-oil centrifuges and two De Laval lubricating-oil centrifuges. Three Condenser Service & Engineering Company lubricating-oil coolers for the main engines, also freshwater coolers. One Condenser Service & Engineering Company salt and water separator, capacity 30 tons per hour. One Condenser Service & Engineering Company distiller, capacity 6000 gallons per day. One Condenser Service & Engineering Company oil and water separator, capacity 30 tons per day. The Condenser Service & Engineering Company also supplied the fuel-oil heaters for the main engines and for the purifiers.

Pumps

The centrifugal pumps installed on the American Manufacturer were supplied by the Warren Steam Pump Company, Inc. ; the geared pumps by the Quimby Pump Company, Inc., and the steam-driven pumps by the Worthington Pump & Machinery Corporation. The pumps and their capacities are. as follows: Motor-Driven Centrifugal Pumps (Warren) 3 vertical salt-water circulating; 950 gallons per minute against head ot 30 pounds per square inch; 25-horsepower motors. 1 vertical fire; 400 gallons per minute against head of 125 pounds per square inch; 50-horsepower motor. 1 vertical lire and general service; 400 gallons per minute against head ot 125 pounds per square inch; 50-horsepower motor. 1 vertical ballast ; 425 gallons per minute, against head of 35 pounds per square inch; 15-horsepower motor. 2 vertical bilge; 425 gallons per minute against head of 3 5 pounds per square inch; ] 5-horsepower motors. 3 vertical fresh-water circulating; 375 gallons per minute against head ot 40 pounds per square inch; 15-horsepower motors. 1 horizontal chilled water circulating; 5 gallons per minute against a head ot JO pounds per square inch; 1/3-horsepower motor. 1 vertical refrigerating condenser; 15 gallons per minute against a head of 25 pounds per square inch; 1/2-horsepower motor.

Geared Pumps (Quimby)

3 lubricating-oil service No. 4 vertical gear-in-head screw pumps with steel bodies and bronze screws' for main engines; 300 gallons per minute against head of 70 pounds per square inch; 20-horsepower motors. 2 No. 1 1/2 AB horizontal gear-in-head Rotex pumps with steel bodies and bronze rotors for lubricating-oil service for reduction gears; 50 gal-lon> per minute against head of 50 pounds per square inch; 3-horsepower motors. 1 No. 4 vertical gear-in-head screw pump with steel body and mehomite screw tor fuel-oil transfer; 225 gallons per minute against head of 35 pounds per square inch; 10-horsepower motor. 2 No. 1 1/4 A horizontal gear-in-head Rotex fuel-oil booster pumps with steel casings and hardened steel rotors; 7 gallons per minute against head of 65 pounds per square inch; 1/2-horsepower motors. 2 permanent oil cargo pumps', 3-C horizontal external gear and double external bearing Rotex pumps, with cast-steel bodies and bronze rotors; 125t gallons per minute against head of 50 pounds per square inch; 7 1/2 horsepower motors.

Steam-Driven Pumps (Worthington)

2 vertical simplex boiler feed, 6 1/2 by 3 1/2 by 8 inches; 15 gallons per minute against a head of 100 pounds per square inch. 1 horizontal duplex salt-water evaporator feed. 3 by 2 3/4 by 3 inches; 20 gallons per minute against a head of 50 pounds per square inch. There is also a Nash rotary wet vacuum priming pump, with a capacity of 15 cubic feet per minute against a 15-inch vacuum, driven by a 1 1/2-horsepower motor, and two manually operated pumps, one for the steering gear system and the other for the bilge from the chain locker.