Photos By Capt. Vincent Daniello
Two parts of a stuffing box squeeze rings of packing around the shaft to form a seal. It’s tightened until it leaks a tiny bit of water to cool packing heated by a spinning propeller shaft. Too much heat hardens packing and makes it leak, and regular over-tightening wears shafts. A longer or shorter hose moves the packing to a new area of shaft, but check with a prop shop on how deeply the shaft can be worn, as this varies by horsepower, prop size, and transmission reduction.
“Over 90 percent of the calls I get are because a stuffing box is too hot, either from over-tightening or using oversized packing,” says Steve Gaston, executive vice president of stuffing-box manufacturer Buck Algonquin (www.buckalgonquin.com). Unfortunately, packing sizes aren’t standard among manufacturers.