Keep The Water On The Outside, Part 2: Stuffing Box

Repacked Stuffing Boxes, 1/13/07

Where the drive shaft and rudder shaft pass through the hull to the underside of the boat, there is a stuffing box that prevents water from entering. This is essentially just a hollow nut around the shaft, in which packing material is compressed to prevent water intrusion. Tightening down the nut compresses the packing. Typically, for a drive shaft, the nut is tightened to the point where the packing allows one or two drops of water per minute into the bilge. The water keeps the stuffing box cool and the packing material lubricated. Eventually, however, the packing material becomes old, hardened, and brittle to the point where it no longer does the job. At that point, new packing is in order.

The picture here is looking down on the rudder post. The reflection is the water that shouldn't be there. Over our first summer, I tried tightening the packing nut, but it didn't prevent the inflow of water. I repacked both the rudder and shaft stuffing boxes while the boat was out of the water for winter. It can be done in the water, but it's a bit more frantic, since water flows in at a pretty decent rate.

The best description of repacking I've ever seen is here: Re-Packing A Traditional Stuffing Box Unfortunately, this wasn't available when I did mine, but I muddled through anyway. I initially ordered the wrong size packing, but after exchanging for the right stuff, it wasn't bad. On some boats, the hardest part is being able to reach the stuffing box (particularly V-drives, where the engine is directly above it). Other than that, it's definitely easy DIY.