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Sternwheeler Betsy Ann, converted to an excursion vessel in 1982, is powered by two Hagglund hydraulic motors driven by hydraulic pumps/diesel engines. High-torque, low-speed hydraulic motors are being used on many paddlewheel vessels all over the world. This form of propulsion transmission and its benefits would appear to be attractive in other applications also. Hydrostatic drives are by no means new for propulsion transmis- sion on paddleboats. One of the first installations goes back to 1972 on a passenger vessel on the Bavarian Lake in Germany. That craft's origi- nal steam engine was replaced by two 230-hp Hagglund hydraulic drives. Similar projects have been realized in Italy, Australia, the Netherlands, and especially in the U.S. A count of the existing hydrostat- ic-powered paddleboat fleet in the U.S. shows about 20 installations. They all rely on Hagglund high- torque, low-speed hydraulic motors, which are particularly favorable in this area. The majority of these ves- sels are newbuildings designed for the growing industry of "nostalgic cruises." The promoters of these ventures have revitalized the old traditions and awakened memories for many senior citizens. Potomac River Boat Company's Cherry Blossom went into service in 1984 as the first paddleboat on that Washington, D.C. river in almost 40 years. She was built by Offshore Shipbuilders in Palatka, Fla., a company that also delivered the 125-foot sidewheeler Andrew Fletcher. Operated as an excursion vessel by Seaport Line in New York Harbor, she is said to be the first large sidewheeler built in the U.S. in the past 60 years. Offshore Ship- builders have plans to construct three more hydrostatic-powered paddleboats. Marine Power, Inc. in Florida, a firm owned by naval architect Wil- liam G. Preston, is well known in the paddleboat field, and has de- signed more than 10 hydraulic-driv- en sternwheelers to date. The firm is optimistic about further similar projects. Their largest existing paddlewheeler is the 100-foot Land- ing Queen, operating on Lake Con- roe, Texas. She was built in sections by Walker Marine at Moss Point, Miss., and assembled on the shores of Lake Conroe. Marine Power is currently working on a 132-foot sternwheeler, the Discovery III, for Alaska River Ways, Inc. LaCrosse Riverboat in LaCrosse, Wise., another specialist in paddle- boats, has so far built 10 sternwheel- ers. The largest is the 125-foot Ta- hoe. Four more sternwheelers are currently in the design stage; all will be hydraulically powered. Like many sternwheelers, the Betsy Ann has a split paddle to assist steering. Steering is further improved with two go-ahead and two back-up rudders. Each of the vessel's 240-bhp diesel engines, operating at 1,100 rpm, drives a variable-volume, pressure-compen- sated hydraulic pump. Each pump powers a torque-arm-mounted Hag- glund hydraulic motor. High-torque, low-speed hydraulic motors or radial piston design are of course applicable in many other types of machinery where similar conditions are encountered. The hy- drostatic transmissions offer the fol- lowing benefits: Efficient torque- limiting by relief valves; smooth, easy speed control from zero to maximum; easy reversing; high torque/inertia ratio, low time con- stant; easy adoption to feedback control systems; freedom to place the prime mover in any suitable space; and simple installation. Compared with high-speed type hydraulic motors, the Hagglund mo- tor offers higher starting torque effi- ciency and elimination of reduction gears. Because of the low-speed ca- pability, this also means faster ac- celeration, quicker reversing, and lower noise level. Hagglunds' hydraulic motor de- sign is particularly well suited for the power ranges concerned—up to 750 hp at 20 rpm per motor. It hydromechanical efficiency is ex- tremely high and it has a reliable low-speed performance, even at 0.5 rpm or less. With a high external load capac- ity, the Hagglund hydraulic motor can be mounted in a bracket or with a torque arm arrangement. The mo- tor is also easily adapted to the drive shaft, with no welding or keyways necessary. Hagglunds foresees a continuing demand for high-torque, low-speed hydrostatic drives for propulsion applications, not only in such "exot- ic" cases a paddleboats but also for thrusters, silent propulsion systems, subsea vehicles, and many other de- manding applications. For further information and free brochures on the Hagglund hydro- static drives, Circle 59 on Reader Service Card Todd Shipyards Relocates Corporate Headquarters To Jersey City, N.J. Todd Shipyards Corporation, one of the nation's leading ship con- struction and repair companies, has moved its corporate headquarters from Manhattan to One Evertrust Plaza, Jersey City, N.J. 07302. The company's corporate staff of some 80 people will occupy the eighth and part of the ninth floors, about 25,700 square feet, under a 15-year lease. Todd was the first tenant to move into the new high-rise build- ing, which is located near Exchange Place. Todd operates shipyards in or near Seattle, San Francisco, Los An- geles, and Galveston, Texas. Its re- cently acquired Aro subsidiary is an international manufacturer of in- dustrial air-powered equipment, in- cluding tools, and aeronautical life- support products and environmen- tal services. The new telephone numbers for the New Jersey office are: (201) 434- 0200 and (212) 668-4700; telex WUI 620100. Sidewheeler Andrew Fletcher, built by Offshore Shipbuilders in Palatka, Fla., is operated by Seaport Line as excursion vessel out of South Street Seaport in New York. JUL JIM'S PUMP REPAIR INC. || W ncorporated 48 55 36th STREET! LONG ISLAND CITY, NEW YORK 11101 JIM LAGONIKOS, President Established 1974 Bob Mooney, Sales & Service Mgr. Reconditioned Coffin & Pacific Feed Pumps Service A-1 Condition Parts Available 24HRS TYPE • F-CG - DE - DEB - IND - T TLX-TWX 718-392-4444 TBA • 12 -16 - 161/2 710-5824847JPRNYK Circle 195 on Reader Service Card PROPULSION UPDATE Hydrostatic Drives Propel Many New 'Old-Time' Paddlewheelers 42 Maritime Reporter/Engineering News
