The Savannah Pilots Association have
been operating their 57 by 16 aluminum pilot boat since 1984. Built at Louisiana
's Breaux Bay Craft the boat
has served them well. When they recently decided to replace the boat's engines they chose a pair of Cummins KTA19 M4 engines producing 700 HP each at 2100 RPM in a medium continuous duty rating.
The change out of engines presented some unique challenges. The Cummins engines are narrower, but longer and taller than those being replaced so that it was necessary to lower the front of the engine beds by eleven inches and fabricate inverted mounts for the rear of the engines and the gears in order to retain the 14 degree shaft angle. At the same time the switch from a spring-type engine mount to rubber soft mounts added to the challenge. The new engines are coupled to ZF660 gears with 2:1 ratio. The 32 X 31-inch props and 2.5-inch shafts from the earlier engines are being retained but a new shaft log has been fabricated as the old one was showing fatigue. While the 2.5-inch shafts will accommodate the increased horsepower, the shaft logs have been designed so that the bearings can be increased to handle a 3-inch shaft in future.
Each new engine package weighs about 1000 pounds more than the old one to around 6000 pounds each including gear. The addition of 2000 pounds of weight is expected to balance out with the additional 110 HP so that speeds will continue to be in the 23 to 25 mile per hour range. The pilots also opted for mechanical controls to the gears and mechanical over electric to the engines' "Century" controls. Cooling employs raw water to a heat exchanger.
The Savannah Pilots also have a second launch. At 77 feet it is larger but older so, explains Chief Engineer Capt Richard Galuk, "If these engines work out as well as we expect, we will be looking to Cummins KTA38 on a replacement for the larger boat."
Work on the repower was completed at the Palmer Johnson yard in Savannah, and the boat will return to service in March.