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Technical Papers
Diesel-Propelled Tanker T1-M-BT1
Source : Pacific Marine Revieuw, Volume 42, 1945.

By L. Chris Norgaard

See also : Drawing Machinery Flat  & General Plan T1-M-BT1

THE UNITED STATES Maritime Commission's latest design for U. S. Navy tankers is designated as design "T1-M-BT1." These tankers are single screw geared diesel propelled. The vessels are of the single deck type, with forecastle, midship, and poop deckhouses, having a straight raked stern and cruiser stern. The cargo capacity is 30,000 barrels, which comprises a cargo of oil and gasoline.
The St. Johns River Shipbuilding Corporation of Jacksonville, Florida, has contracted to build 12 tankers of this design. The detail designs and working plans are furnished by the firm of Joslyn and Ryan, Naval Architects and Marine Engineers of San Francisco, California, who for the past four years have been one of the leading design agents for the U, S. Maritime Commission and the U. S. Navy.

Principal Characteristics

Length o.a.
325' 2"
Length between perpendiculars
309' 0"
Beam (molded)
48' 2"
Depth to main deck (molded)
21' 9"
Displacement (full load, tons)
Design draft (full load)
19' 0"
Shaft horsepower (normal)

The ships will be constructed on the longitudinal system of framing throughout the cargo tanks, with the ends framed transversely. The hull structure will be of all-welded steel construction and oil tight for the extent of the cargo tanks. The ships are divided into six main cargo tanks, which are divided by a centerline longitudinal bulkhead, giving a total division of 12 cargo tanks. Each tank is fitted with an ullage trunk and connection will be fitted to each cargo tank for Butterworth tankcleaning.
The rudder and stern post are of "contra" form.
All watertight doors are of the quick-acting type. All joiner doors within the magnetic sphere of the compass are built of aluminum.
The masts of tapered tubular stes are stepped on the main deck. One three-ton cargo boom of tubular stee is rigged to both the mainmast am the foremast.
These vessels are being built under the special survey of the American Bureau of Shipping, and classed ABE oil carriers, "AMS" and "EAC.' Equipment and construction meet the latest United States Coast Guard regulations, also the International Load Line Convention for the Safety of Life at Sea, Senate Report No. 184 U. S. Customs Admeasurement, Suez Canal Tonnage Rules of Navigation, and the Panama Canal Regulations.
The latest navigation equipment, instruments, and signaling apparatus are to be provided, including gyro compasses.

The main deck in the poop provides space for the crew's quarters, galley, dry stores, refrigerated stores, dry provisions, and steering gear. The poop deck houses additional crew quarters, officers' staterooms, ship's offices, officers' pantry and mess, and sick bay. The main deck in the midship house is arranged for two potable water tanks, each of 20-ton capacity, s.d. stores, canvas stores, clipping room, CO2 room, battle dressing station, damage control office, laundry, and electrical stores and workshop. The bridge deck in the midship house provides for officers' staterooms and lounge, and captain's stateroom and office. The navigating bridge is located on the midship house and incloses the wheelhouse, radio room, and radar, and chart room. The forecastle accommodates a carpenter shop, armory clipping room, bos'un's stores, and resistor, and windlass rooms. The first and second platforms, which are located Just below the forecastle deck, contain ample capacity for cargo stores and ammunition.

Each living space is ventilated, heated, and insulated to insure a comfortable temperature in all climates. All bulkheading in houses and quarters is of incombustible materials.

The ship's refrigerator spaces are insulated with mineral wool of the blanket type. The floors of the refrigerators are covered with 1 1/2" mastic. The refrigeration system is operated by two compressors each of the multi-cylinder, single acting marine type using freon as a refrigerant.

The steering gear is of the Rapson slide, double ram, electro-hydraulic type. The gear is operated by two independent power plants, and is designed to provide independent operation of the rudder by either ram. Steering will be done by telemotor transmission.

The heating of living and working spaces is supplied by a steam generating plant of the self-contained packaged type with a normal capacity of 2500 Ibs./hr., developing a steam pressure of 50 pounds per square inch for fuel oil heaters and oil heating coils, and a pressure of 3 5 pounds per square inch to the ship's heating and service system. These vessels are outfitted with a distilling plant, which consists of a packaged distiller and evaporator. The plant delivers 15 short tons per day at 2,5 gallons per minute.

A complete firemain system has been provided. This system is supplied by risers from the main fire pump, which is of the vertical centrifugal volute type, and delivers 450 gallons per minute at 100 pounds per square inch. The firemain is led fore and aft along the catwalk where exposed to the weather. All magasines are protected by sprinkling systems connected to the firemain. Fixed carbon dioxide smothering systems are installed to protect the after cargo pump room, inflammable stores, cargo hold, and cargo tank hatches. The firemain and fire-fighting equipment is designed to meet all requirements of the U. S. Coast Guard.

The liquid cargo system consists of three fore-and-aft deckmains; the port main will transfer aviation gasoline; the center main, motor gasoline; and the starboard main, diesel oil. These deck mains terminate in port and starboard loading and unloading connections at two stations. Each main has an electrically-driven cargo pump of the horizontal rotary type delivering 730 gallons per minute at 80 pounds per square inch. A pump room forward is provided for a fresh water cargo pump which operates a fresh water main to the aviation gasoline tanks, as the vessels also carry fresh water cargo when aviation gas is not carried. The fresh water pump is the vertical centrifugal volute type having a capacity of 700 gallons per minute.

The main propelling machinery consists of a single diesel engine driving the propeller shaft through a reduction gear and thrust hearing.

The main engine is an exhaust turbo supercharged diesel designed and built by Enterprise Engine and Foundry Co., San Francisco.

The reduction gear is designed to give a ratio of 2.586:1. The pinion and gear are of the single reduction double helical type.

The auxiliary diesel generators, port and starboard, are 240V-DC two wire type, and have a capacity
of 250 kw.

Twenty tankers of similar design are being built for the British Merchant Fleet. These tank vessels are designated as design T1-M-BT2, 14 of which are being built by Todd' Houston Shipbuilding Corporation of Houston, Texas, an'd six by J. A, Jones Construction Co., Panama City, Florida, from the plans of Joslyn and Ryan, Naval Architects.

List of Vendors for BT-1
(List includes only main items and vendors known to date):
Main Engine: Enterprise Engineering & Foundry Co.
Main Cargo Pumps: Smith-Meeker Engineering Co.
Motors for Cargo Pumps: Electro Dynamic Works.
Line Shaft Bearings: United American Metals Corp.
Propeller: Baldwin Locomotive Works.
Emerg. Diesel Eng.& Gen.: Baldwin Locomotive Works.
Steam Generating Plant:  Poster-Wheeler.
Evaporator and Distiller: Bell & Gossett Co.
Refrigeration Compressors: Carrier Corp.
Deck Winches: Sedgewick Machine Works, Inc.
Windlass & Warping Winch: Globe Hoist Co.
Fresh Water Cargo Pump: Dayton Dowd Pump Co.
Steering Gear: Baldwin Locomotive Works.
Binnacles and Compasses: Kelvin W Wilfred O. White Co.
Laundry Equipment: G. H. Bishop Co. Grand Rapids Store Equip. Co.
Boat Davits: Welin Davit & Boat Corp.
CO2 Systems: COs fife. Equipment Co.
Gen. & Dist. Switchboard: Stirling Switchboard Mfg. Co.
I. C. Switchboard & Emerg. Swbd.: Zinsmeyer Co.