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Baltimore Mail Liners Demonstrate Speed, Utility and Economy in Service Co. inaugurated a new _ passen- ger, fast freight and mail serv- ice between Baltimore, Hampton Roads ports and Hamburg, with a call at Havre, on July 2, 1931, when the S.S. Crry or BAttrmore, the first of five converted ships, sailed on her maiden voyage. As they were fin- Te: Baltimore Mail Steamship ished, at approximately monthly in- . tervals, the other four ships were put in commission and fitted into the schedule, so that for several months there have been weekly sailings of these ships from Baltimore. The five ships, renamed Ciry OF BALTIMORE, CiTy OF NORFOLK, CITY OF Newport News, City or Havre and Ciry oF HAMBURG, were formerly the INDEPENDENCE, VICTORIOUS, ARCHER, Ecuipse and INVINCIBLE, built for the United States shipping board in 1918. They had originally a deadweight ton- nage of about 11,800; length between perpendiculars of 440 feet; beam, 56 feet, and a normal sea speed of 10% knots. Increased Length for Speed After conversion of these five liners, which was done at the Federal Ship- building & Dry Dock Co., Kearny, N. J., their characteristics have been changed to the following: Length over all, 507 feet % inch; length between per- pendiculars, 486 feet; breadth molded, 56 feet; depth molded, 38 feet to shelter deck. The displacement loaded at a draft of 24 feet *4-inch became 13,525 tons in the case of the Crry oF BALTIMORE; her gross tonnage, 8424, and net tonnage, 5220. Before conversion there were no passenger accommo- dations, while now 81 cabin passengers can be taken care of on each ship. The cargo capacity in the new condition is 5000 tons and in cubic feet, 427,- 225 bale, 26,610 refrig- erator, 7200 baggage and 7025 stores. The cruising speed was in- creased to 16 knots and on her trial trip the CITY OF BALTIMORE made 18.25 knots. The problem presented to the naval architect, Gibbs & Cox Inc., was to convert these 1014- knot cargo ships into 48 Engine room, City of Baltimore. reduction gear. By H..7. Dyer 16-knot vessels and add passenger accommodations for 81 persons. The lines of the original ships were satisfactory for the 10%-knot speed, but totally unsuited for 16 knots. A study of this part of the problem and extensive model experiments revealed that by removing the bows and sterns, and adding about 40 feet at the for- ward end of the ships, with a new design of bow, fitting a new stern frame and rudder, it would be possi- ble to so improve and fair the lines of the ships as to drive them at 16 knots with a reasonable increase in shaft horsepower. This part of the change worked out so that the appearance of the vessels has been materially improved. The watertight subdivision of the vessels has been brought up to a two compartment standard by the installa- tion of additional bulkheads and the vessels comply throughout with the re- quirements of the International con- fernce for safety of life at sea. The original machinery installation provided for developing 2900 shaft horsepower with a single propeller. To increase the speed and provide ample margin at 16 knots, a plant of 9500 shaft horsepower was installed with the limitation that the original ma- chinery spaces could not be enlarged, and that a single shaft arrangement must be retained. A study of this The author, H. T. Dyer, is a member of the staff of Gibbs & Cox, Inc., naval architects. MARINE Review—April, 1932 im De Laval steam turbines and double An efficient dependable modern propelling pela problem resulted in the installation of four oil burning Babcock & Wilcox boilers of 20,800 square feet total heat- ing surface, operating normally under forced draft, supplying steam at 275 pounds and-100 degrees Fahr. super- heat to a DeLaval steam turbine, fit- ted with double reduction gears, turn- ing a manganese bronze propeller of about 20 feet diameter at 95 revolu- tions per minute, made by the Amer- ican Manganese Bronze Co. In addi- tion to the main units the DeLaval Steam Turbine Co. also supplied the boiler feed pumps which are. 2-stage driven by DeLaval turb?rnes and each designed for 250 gallons per minute capacity. The same company also sup- plied the turbines and worm gears for driving the fans. Good Turbine Economy This particular pressure and temper- ture was selected as being capable of giving good turbine economy, without the complications that would be re- quired to maintain the high purity ¢¢ teed water had considerably higher pressures and temperatures been used, although it was recognized that a cer- tain loss in overall efficiency must De accepted. Throughout the engineering plant simplicity of parts and arrangements was the keynote, so as to reduce the initial cost of the changes, and at the same time produce a plant that would be easy to operate with the minimum of personnel and upkeep expense. Auxiliary equipment on the convert- ed ships include: pumps, Worthington Pump & £%Machinery Corp.; windlass Hyde Windlass Co.;. 12 win- ches, Hyde Windlass Co.; steering engine, American Hoist & Der- rick Co.; and electric generators, Westing- house Hlectric & Mfg. Co. Interior arrange- ments of the_- ships were materially changed, and an en- tirely new deckhouse fitted, to accommodate passengers. On the boat deck forward, un- der the bridge, are located rooms for the captain and various other ship’s. officers. Forward on the deck below, is the lounge;