Leaks around the propeller shaft

I seem to be spending more time on maintenance and repairs than sailing, at least for the past two to three years. But it’s an old boat, and I like to keep her in good shape. March 2021, it was time to take her up for cleaning and new bottom paint. The stuffing box has been leaking a little ever since I installed the new engine and drive line in 2015, and had increased last year. It needed to be fixed. It leaked both oil and water, and made a mess in the bilge!

This is the end result. It looks tight, but it works!

It didn’t look good before this, though (oil tank and lines have been removed):

Removing the stuffing box revealed a stern tube in poor condition. It is made from fiber glass, but was cracked and broken. Here was the cause for the leak, obviously. I had thought it was the stuffing box.

Removing the Sigma Drive was not easy! In theory, it would come off by screwing in the bolts as shown, but it took quite some effort with other tools too.

The in board part of the tube:

To get the propeller shaft out, I had to lift the engine ca 20 cm forward.

Intrusion of salt water had not been good for the Sigma Drive. I decided to swop it with a new Centaflex. The Sigma Drive from Bruntons is a good coupling for its purpose. It allows for up to three degrees of misalignment, but it has no torsional flexibility. The combination of a mechanical gear box, the Sigma Drive, and the Autoprop has caused very abrupt and almost brutal gear shifts. Changing from reverse to forward has felt like someone hit the hull with a sledge hammer, when the Autoprop turns its blades around from reverse to forward position. With the rubber connection between the propeller shaft and the gear box in the Centaflex, I hoped for a smoother gear shift.

But first I had to fix the tube. As no replacement would be found, I tried to find a solution of my own. Starting with a PVC tube of 35 mm inner diameter, I built up the outer diameter with epoxy and fiber glass, until I had a couple more mm than the 48 mm that was required. Then I turned it down in a custom made lathe. Yes, I shall tidy up my workplace!

The result:

Mean while, Javid was cleaning and polishing outside.

The plan was to be up on the shore for a week, going back in just before Easter. But the extra work meant another week before we could hit the water again.

I am very happy with the result. The new tube and stuffing box is (almost) leak proof. I have done away with the oil lubricated stuffing box, making for a clean bilge. And as I hoped, the gear shifts are now a pleasure. Much smoother, as it should be! We sailed home in a nice breeze, with a smile! I can recommend Åmøy havn!

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