How do I replace the stern gland on a Hallberg-Rassy Rasmus 35?

Replace the complete stern gland on your Hallberg-Rassy Rasmus 35 with the boat ashore, after identifying the existing seal and measuring the propeller shaft and stern-tube connection. This normally means disconnecting the shaft coupling and sliding the shaft aft far enough to fit the replacement, though repacking alone may leave the shaft in place.

Identify the fitted gland

Find the leak first. Dry the assembly and look for water tracks around the shaft, hose connections and stern tube. A loose clamp or split connecting hose needs different work from worn packing or damaged sealing lips.

Many Rasmus 35s have acquired replacement engines, shafts and glands over the years, so the model name alone is not enough to order parts. Identify the arrangement:

• Packed stuffing box: a metal body with a large compression nut and locknut, or a follower held by two studs. Some installations also have a greaser.
• Rubber lip seal: a moulded rubber body clamped to the stern tube, such as a Volvo Penta seal.
• Mechanical face seal: a rubber bellows carrying a stationary face against a stainless rotor, such as a PSS.

Measure the clean shaft with vernier callipers and the outside diameter of the stern-tube spigot beneath the hose. Record the available installation length and any vent or water-feed connection. A 25 mm shaft is not interchangeable with a 1-inch shaft: 1 inch is 25.4 mm.

Plan the shaft movement

Inspect the coupling, propeller aperture and rudder clearance before ordering the replacement. The shaft needs to move far enough to release its forward end from the coupling and give the seal a clear path. The propeller may limit that movement. The installation determines whether you need to remove the propeller, withdraw the shaft further or work on the rudder; rudder removal is not automatically required.

Have the yard secure the boat properly ashore and isolate the engine starting circuit before working on the shaft.

1. Photograph the assembly, measure its position and mark the coupling relationship.
2. Support the shaft so its weight cannot bend the gland or load the gearbox flange.
3. Undo the coupling-to-gearbox bolts, then release the shaft coupling's clamp bolts, retaining screws or nut as applicable.
4. If the hub is seized, use the appropriate puller or coupling-removal tool. Do not hammer against the gearbox or use its flange as a pulling reaction surface.
5. Slide the shaft aft under control, retaining any key and preventing the shaft from escaping outwards.

Allow time for a stubborn coupling. Corrosion here often turns a straightforward maintenance job into a larger yard operation.

Inspect and fit the gland

Remove the old gland and inspect the shaft where the seal runs. Deep grooves, pitting or a wear ridge can make a new lip seal leak immediately. Ask a marine engineer to assess whether the seal can run on a sound section of shaft or whether the shaft needs repair or replacement.