Waukesha Engine Division of Dresser Industries announced this year that it will manufacture a new family of large-bore marine diesel engines under a license from Sulzer Brothers Limited of Winterthur, Switzerland. The new engines, scheduled for production in 1982, will be called the AT25 series. They are rated from 1,230 to 4,320 maximum continuous bhp (985 to 3,223 kw) for propulsion and up to 3,040 kilowatts for ship's service electric sets at 1,000 rpm.
Available in four basic models—6- and 8-cylinder in-line and 12- and 16-cylinder Vee versions — the AT25 series engines will have a bore of 250 mm and stroke of 300 mm (9.84 by 11.8 inches) and are capable of operating on heavy fuel.
The V-16 model 16V-AT25 has maximum continuous ratings of 4,320 bhp at 1,000 rpm, 4,000 bhp at 900 rpm, and 3,520 bhp at 750 rpm. Its ship's service electrical ratings include 2,800 kw, 60 Hz at 900 rpm, and 3,040 kw, 50 Hz at 1,000 rpm. Maximum continuous ratings of the V-12 model 12V-AT25 include 3,240 bhp at 1,000 rpm, 3,000 bhp at 900 rpm, and 2,640 bhp at 750 rpm, with ship's service ratings of 2,100 kw, 60 Hz at 900 rpm, and 2,280 kw, 50 Hz at 1,000 rpm.
The in-line, 8-cylinder model 8L-AT25 has maximum continuous ratings of 2,160 bhp at 1,000 rpm, 2,000 bhp at 900 rpm, and 1,760 bhp at 750 rpm. Ship's service ratings include 1,400 kw, 60 Hz at 900 rpm, and 1,520 kw, 50 Hz at 1,000 rpm.
The smallest in the family, the in-line, 6-cylinder model 6L-AT25 has maximum continuous ratings of 1,620 bhp at 1,000 rpm, 1,500 bhp at 900 rpm, and 1,320 bhp at 750 rpm. Ship's service ratings are 1,050 kw, 60 Hz at 900 rpm, and 1,140 kw, 50 Hz at 1,000 rpm.
Design features include rigid, one-piece cast crankcase and cylinder block with underslung crankshaft for greater stiffness. Bore-cooled cylinder heads with water-cooled valve seats permit operation on heavy fuels. The application of pulse type turbocharging provides excellent performance and fuel economy at part or full load.
In addition to the AT25 series, Waukesha offers two other families of engines. Its VHP marine diesels are the result of a 10-year design program to provide a reliable, high-performance engine for workboats and fishing trawlers in the intermediate horsepower range. Outputs range from 416 to 1,636 continuous bhp (310 to 1,220 kw) at 1,215 rpm.
Complementing the AT25 and VHP lines are the smaller mid-range VS series marine diesels. They are rated up to 348 continuous bhp (260 kw) at 1,900 rpm for propulsion and 235 kw at 1,800 rpm in ship's service generator sets.