A metal cylinder filled with water-resistant grease fitted close to the stern tube on a narrowboat. Used to provide a frequent supply of grease to the stuffing box/stern gland to keep the seal watertight and reduce wear on the propeller shaft.

Stern gland greaser on a narrowboat helps to reduce wear on the propeller shaft
Stern gland greaser on a narrow boat
Filing the stern gland greaser on a narrowboat

Filing The Stern Gland Greaser… Get Your Gloves On!

The stern greaser is a vital component in the battle to keep water out of the narrow boat engine bilge and to maintain lubrication of the propeller shaft.

Standard narrow boat grease units are composed of a vertical cylinder of brass or stainless steel, connected to a base plate & with a large threaded “T” handle connected to the top of the cylinder with a screw down cap.

The base plate has a connection point for a tube which is in turn connected to the stern gland or stuffing box. The stern gland is the heavy brass collar that supports the prop shaft as it exits the stern of the boat. Familiarise yourself with the position of all these components.

The cylinder is filled with grease and whilst cruising we turn down the “T” handle which delivers grease under pressure into the stern gland, thus lubricating the shaft and preventing water ingress. It is good practice to turn down the stern gland whenever you turn off the engine after rotating the prop, just so you feel pressure at the “T” handle.

Obviously the grease gets used up. This is how to replace it with the minimum of fuss.

Use specialist water resistant grease only. The most common is a product called K99 & comes in a container which has a metal disc inside with a hole in the middle. Other types are available so ask your chandler.

  1. Get your latex gloves on.
  2. Undo the main body of the cylinder from its base. (They do come apart but you may need to use your adjustable grips).
  3. Unscrew the cap from the cylinder and withdraw the “T” handle and plunger.
  4. Wind the ‘T” handle out of the cap so the threaded bar is fully wound out.
  5. Take the lid off the grease container.
  6. Press the empty cylinder down over the hole in the plate inside the grease container. This forces grease into the cylinder.
  7. Scrape off the excess grease from the top & bottom of the cylinder back into the container.
  8. Screw the cap & extended handle back onto the cylinder.
  9. Screw the cylinder back onto its base.
  10. Wind down the “T” handle until resistance is felt.
  11. Wipe all excess grease off the grease unit.

Filing The Stern Gland Greaser

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