Fair warning – plenty of blathering on about technical stuff below.
Back in Ipswich, we contacted Fox’s Boatyard to agree on a plan for investigating our new rudder bearing leak. After a couple days at anchor, the team was able to make room for us at the service dock.
We used those days to have a thorough look at the part of the rudder post that we could see, and it looked like we could see the problem, or at least part of it. A series of small scratches in the rudder post extended upwards from the top of the bearing. None of the scratches were deep, but a couple of them were easily noticeable by running a fingernail along the stainless rudder shaft. The rudder post was in near-perfect condition when it first came out of the boat, so the scratches must have been made either when the rudder was stored in the boatyard, or when it was reinstalled along with the new bearing.
The lower rudder bearing used on a Hallberg-Rassy 54 like Oso has three separate lip seals that are designed to keep water from being driven up the rudder post – there’s one seal at the bottom of the bearing, closest to the ocean, and two more at the top of the bearing. Since water is coming into the boat, that means that all three of the seals are leaking. If the scratches on the side of the rudder post extended the full height of the bearing, then that could provide a path for water to work its way into the boat.
We arrived back at Fox’s service dock, and after a couple of hours of inconclusive investigation inside the boat we agree that Oso would need to be lifted out of the water, again, so that the rudder could be lowered out of the boat, again. Both of these things were done quickly and carefully, and everyone was interested to see the extent of the damage to the rudder post.
Much to our surprise, the scratches were only a half inch/1cm or so in length. That would be enough to make the upper seal leak, but it couldn’t explain why water was able to get through the other two seals to reach the upper seal in the first place.
After much investigation, we discovered that the seals that were installed by the manufacturer of the bearing were missing the garter spring, a kind of flexible retaining ring that helps to push the lip of the seal against the rudder post to ensure that there’s a good seal. When contacted, the manufacturer explained that they removed the garter spring because it was made of mild steel, not stainless steel, so that it would rust away.
We were absolutely shocked – the exact size seal used in the rudder bearing is commercially available with a stainless steel garter spring. So it is crazy to use a seal with a mild steel spring in an application where the seal will be exposed to corrosive sea water, and it’s probably even crazier to “solve” the problem of a rusting garter spring by discarding it in the first place!
So it turned out that we had two problems with the rudder bearing. First, the removal of the garter springs meant that the seals didn’t work as well as they were designed to do. They could hold the water out of the bearing while the boat was at rest, but as soon as the rudder was put under any force from sailing they leaked a little bit. Second, the scratches at the top of the rudder post meant that any water that made it through the two lower seals would definitely find it’s way out of the topmost seal.
Of course we would have much preferred that the new rudder bearing was perfect the first time. But when it obviously wasn’t, at least the crew at Fox’s took responsibility and worked hard to make things right. Adam, the super-skilled stainless fabricator, welded over the scratches and then polished nearly all the weld away, returning the rudder post to nearly new condition. And project manager Michael and chief engineer Mark found a source for replacement seals and got them shipped and installed as quickly as possible. When it came time to reinstall the rudder, a team of 7 folks were on hand to make sure that the rudder post wasn’t scratched again as it was lifted back into the boat.
And now we know a lot more about rudder bearings and seals than we ever thought we would…
