Challenging Repower for Savannah Pilots

The repower presented some interesting challenges as the Cummins engines are narrower but longer and taller than those they replaced. It was necessary to lower the front of the engine beds by 11″ and fabricate inverted mounts for the rear of the engines and the gears in order to retain the 14º shaft angle.

The simultaneous 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 by 31″ props and 2.5″ shafts from the earlier engines were retained but a new shaft log was fabricated as the old one was showing fatigue. While the 2.5″ shafts will accommodate the increased horsepower, the shaft logs were designed so that the bearings can be increased to handle a 3″ shaft in future.

Each new engine package weighs about 1,000 pounds more than the one it replaces but the additional weight is balanced by additional horsepower, enabling a continuation of speeds in the 23 to 25mph range.

Work on the repower was completed at the Palmer Johnson yard in Savannah and the boat returned to service last month.

MJ Information No: 17001