SNAME Los Angeles Holds First Meeting, Discusses Low Power Marine Steam Cycle
The first meeting of the 1981- 1982 season of the Los Angeles Metropolitan Section of the Society of Naval Architects and Marine Engineers was held recently aboard the Princess Louise in the Port of Los Angeles.
George Stiehl, incoming chairman of the Section, opened the meeting and introduced the new officers: George Henning, vice chairman; and Dr. Maxwell Cheung, secretary-treasurer. Mr. Henning then introduced Paul Cromer of Todd Shipyard, San Pedro, author of the evening's paper titled "A Marine Steam Cycle for Low Powers." The author described a steam cycle for propulsion plants of 5,000 hp or less, and stated that the purpose of the cycle was to provide a means for smaller vessels to use coal as a fuel. He utilized preliminary heat balance data for two sets of steam conditions for a plant of 2,500 hp as a basis for the discussion. Mr. Cromer said that recent orders for large coal burning marine steam turbine-powered ships is the result of present and projected prices of petroleum products and questioned the lack of similar new technology for smaller vessels that are usually powered by diesel or gas turbine systems. He cited two developments that may make a simple, low-powered, coal burning turbine plant possible ; the refinement of the controllable- reversible pitch (CRP) propeller; and the use of the main reduction gear for driving major plant auxiliaries.
The CRP propeller, when used with a geared steam turbine, eliminates the astern turbine and reduces the speed range over which the propulsion turbine is required to operate. The use of the main reduction gear for driving major auxiliaries, such as the shaftdriven generator, is common for ships with DRP propellers since most ocean transit time is spent at one turbine speed and power setting.
The author detailed the beginning steps in the design of a marine steam plant: the development of the steam cycle suitable to the application; and the prediction of the cycle's performance for a number of steam conditions.