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Mid-Coast To Build N&SA-Designed Voith Tractor Tug Jack Wilskey, president of Mid- Coast Marine in Coos Bay, Ore., recently signed a contract to build a new Voith tractor tug for Wil- lamette Tug & Barge, a division of Riedel International, Inc., Port- land. The tug was designed by Nickum & Spaulding Associates, Inc. (N&SA), Seattle, Wash. This trend-setting vessel will have a Voith-Schneider cycloidal propel- ler system shipped to the United States for use in this U.S.-built and operated commercial tug. The new tractor tug will replace the steam-driven sternwheeler S/S Portland, designed by one of N&SA's parent companies—W.C. Nickum & Sons Co., Inc. Mid-Coast Marine, Inc., the builder of the new tractor tug, has been constructing workboats since 1956. They are known for a broad range of tugboats built for the logging and dredging in- dustry, as well as for a new line of fishing trawlers which were introduced in 1970. Nickum & Spaulding has a long history of designing unique work- boats. The firm recently designed a Voith tractor tug, which is cur- rently undergoing sea trials in Singapore. This tug, and her sis- ters that are yet to follow, will see ship handling service in the Arabian Gulf. Design of the boat for Willamette Tug & Barge, however, has started a West Coast trend as evidenced by other recent building contracts for Voith tractor tugs. This propeller system will en- able the tractor tug to move more quickly and precisely while easing ships into and out of their Port- land berths. The first meeting of the 1981- 1982 season of the Los Angeles Metropolitan Section of the So- ciety of Naval Architects and Marine Engineers was held re- cently aboard the Princess Louise in the Port of Los Angeles. George Stiehl, incoming chair- man 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 Principal Dimensions Length Overall . 95'0" Beam 32'0" Draft 14'9" Horsepower 2,600 Complement . . . 6 Fuel 25,800 gallons 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 ves- sels to use coal as a fuel. He uti- lized preliminary heat balance data for two sets of steam con- ditions 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 pro- jected prices of petroleum prod- ucts and questioned the lack of similar new technology for small- er vessels that are usually pow- ered by diesel or gas turbine sys- tems. He cited two developments that may make a simple, low-powered, coal burning turbine plant pos- sible ; the refinement of the con- trollable-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, elim- inates the astern turbine and re- duces 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 shaft- driven 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 begin- ning steps in the design of a ma- rine steam plant: the develop- ment of the steam cycle suitable to the application; and the pre- diction of the cycle's perform- ance for a number of steam con- ditions. W S A ENGINEERS TAKE VOU TO THE TOP Maintenance-free aluminum gangways and accommodation ladders designed and fabricated by W &. A Engineers come in standard and custom designs Accommodation ladders are available with upper rotating platforms, fixed tread or feathering tread and handrails adjustable lower platforms and varying widths. DESIGNERS S ^ FABRICATORS W Si A ENGINEERS, INC. 4Q4Q Veterans Highway • PO Bdx 73DB • Metairie, Louisiana 7DDD5 • [5D41-8B7-D1 31 SNAME Los Angeles Holds First Meeting, Discusses Low Power Marine Steam Cycle Shown during the first 1981-82 meeting of SNAME, Los Angeles Metropolitan Sec- tion, are, left to right: George Stiehl, chairman of the section; George Henning, vice chairman; Paul Cromer, author and presenter; Dr. Maxwell Cheung, secretary- treasurer; and Gary Cash, public relations chairman. Outboard Profile 28 Write 351 on Reader Service Card Maritime Reporter/Engineering News
