Talk:Replacing Solway Rudder Bearing

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Article by Hugh Morrison November 2014

When a boat gets to a certain age, there is a growing collection of issues that need to be attended to, most of which have been part of an effort to avoid the work involved. But when the lower rudder bearing, or bush, gets a bit rattly and the surveyor of some years previous has said to ‘keep an eye on it’ there comes a moment when a decision is made, new bushes are sourced and the job becomes an inevitable part of a cold, rainy, muddy and sometimes frustrating renovation. In principle, this is one of the most straightforward jobs on a boat. A transom hung rudder is the simplest - and so simple that it hardly needs dealing with - no holes to be dug and a simple lift away from the hull. A rudder at the back end of a keel or skeg with pintles top and bottom is also simple. The weight of a rudder can be a surprise, and is always to be taken into account. A rudder stock in a rudder tube is the one with the work involved, and this is a description of such a rudder mounted on a Westerly Solway, a bilge keel 36’ ketch. This has wheel steering, a relatively short 2” stainless steel rudder stock inside a 2¼” rudder tube that rises to the top bearing, mounted on an encapsulated steel cross beam, then to the steering quadrant, just beneath the aft cabin bunk where the emergency tiller can be mounted and the boat can be steered from the aft hatch. Although all the retaining bolts are metric, the stock and tube are in imperial measurements on this boat. Because it is a bilge keeler, the rudder blade is itself shorter in depth but longer fore and aft than its fin keeled cousins (Conway and Medway and W35) and has a narrow ledge or plate at the bottom, often used to improve the flow over the rudder. This boat is generally very easy to work on. This rudder can just be lifted by two people when it is clear of the boat. It is heavy and unwieldy.

1. We measured the approximate length of the rudder stock from the top of the rudder blade to the top of the rudder stock and dug a hole that deep from the bottom of the rudder blade, and added half a hand’s depth to account for clearance and misjudgement.

2. We placed some blocks close to the rudder so that a jack could be placed underneath. In this case a small hydraulic jack was used. The jack was raised so that it contacted the bottom of the rudder and locked in place.

Before any attempt at lowering took place, a strong line was tied from a position on the boat vertically above the rudder stock and brought up firm against the bottom of the rudder. This was useful for lowering the rudder, and should have been useful when lifting the rudder back in to position, although ratchet type cargo ties were infinitely better. This line was lashed fore and aft on to the rudder blade to prevent it slipping off.

4. The rudder and the people working on it must be safe once the pins and bolts that secure it in place start to be removed.

5. With the weight of the rudder now held by the jack, I tied the steering wires to prevent them falling off any of the guide sheaves, marked their position and undid them, removing all the retaining bolts and pins, the quadrant, the parallel key, and any other obstructions. The rudder was slowly lowered using the jack and the line around the bottom of the rudder. The issues that have been most testing were digging the right sized hole - some boatyards are concrete and digging would be out of the question: the boat would have to be chocked up high enough to provide clearance. If you are lucky it will be clay or sand and not rubble or rock. This is a really physical job - a previous boat needed a 60cm hole in a yard of sand and stone, and a friend’s boat needs over a metre. It is a couple of hours work. Preparation for raising the rudder again was at least as important as lowering it. Because the bottom bearing was loose lowering the rudder wasn’t obstructed by tight bearing clearances. Things could have happened in a bit of a rush, but some care was taken to prevent that. 6. Having removed the rudder, I compared the old with the new. I measured the size of the rudder tube and compared this measurement with the new bearings. If I was to have had new bearings made up at this point, I would have made notes. The old bearings were tight in the rudder tube because they were old, so I cut them out carefully with a hacksaw blade. 7. As I already had new bearings, I offered them up to see that they fitted. If they are a tight fit they would contract once they are driven home, and this would interfere with the fit of the rudder stock. If they are loose, then that could be a problem. The hope was to find that all was well, replace all the bearings, apply some gentle lubricant to the rudder stock and with some help, replace the rudder. 8. These bearings are not nylon as it swells in water and could possibly seize up the rudder stock. Although no specification is given (other than ‘made to Westerly specifications’) they appear to be acetal (sometimes sold as Delrin) which is what I would have chosen were I to have had them made up. Once everything finally fitted after considerable resizing of the bearings, I replaced everything at the top end in reverse order.

This is a job that could take four or five hours from start to finish, but in the case of our rudder, it took three days. • It rained, so the rudder was lowered into the pool of water that had been a neatly dug hole, surrounded by the clay rich spoil that clung to shoes, waterproofs and pretty much everything else. • Replacing the rudder is a simple process. Difficulties arose because the bearings were oversize, and the rudder was difficult to align because lifting the rudder out of its pit in the ground was initially difficult - until a friend turned up with some ratchet luggage ties which gave us better leverage. • The top bearing was around 3mm over size, and without a lathe it was only possible to grind the excess away. These bearings are naturally slippery but hard, almost like bronze, and grinding is a slow process which includes frequent visits to the boat itself, climbing up the ladder, distributing more clay around the cabin, and trying the bearing for size. At the end of day one this had been achieved. • On day two the lower bush was inserted into the lower end of the rudder tube, and found to be a good fit. It was removed and tried on the rudder stock, with the assistance of a wooden block. It was a good push fit. But when the bush was pushed home into the rudder tube, and the rudder offered up it would not fit. Problems with alignment were blamed. The process was modified by putting the bearing on to the stock, and offering up the rudder again so that alignment was more manageable. The stock went in only as far as the top of the lower bearing, and then wouldn’t go any further. We jacked the rudder up with some force but found that not only was the bearing starting to bulge, but we had lifted the back end of the boat a few millimetres, which isn’t a good thing. When we removed the rudder yet again, the bearing was clearly too large for the tube. What seems to have happened is that in trying the bush on the rudder stock with the assistance of a wooden block it had expanded enough to cause interference. This had to be ground down to fit. • At the top of this rudder tube is a housing that screws down on to the top of the rudder tube and is then bolted in place. It holds the top bush in place and also contains a water seal - basically the sort of seal used as an oil seal, a rubber encased metal ‘washer’ with a lip that is held open by a stainless steel spring. The water seal is useful in preventing sea water ingress caused by following seas when the stern tucks down. The old seal was a mucky collection of bits of rubber.

On the third day, using some webbing straps (of the kind used for holding down things on roof racks or trailers) to help raise the rudder again, the process took less than an hour. A new parallel key had been cut and filed and the quadrant was refitted over this. This should be made of key steel, not mild steel. If you know the size, one can be ordered on line.

There was still one snag. The rudder is prevented from falling out of the boat by a substantial stainless steel collar with a through bolt at the top of the stock. The new bushes were slightly oversized and the plastic collars that prevent the bushes slipping up or down the tube needed adjustment. Fortunately the amount needed was small, and by firming up the bolts of the saddle and lightly sanding off the surface of the flat thrust bearing at the top, the bolt could be inserted through the collar.

The final fitting completed, the steering was swung side to side several times to check it, and the cable tension rechecked. The three days that this took were a basic 8.30 - 9.00 start to a 3.30 finish on winter days with some comfortable coffee breaks and the generous assistance of two others. Problems were down to two things - in particular the size of the bearings supplied, and to a lesser extent the alignment of the rudder stock when refitting it - simply because getting a line under the centre of gravity of the rudder was difficult. But once the rudder was high enough to get the hydraulic jack under it, the job was easy, and made a bit easier by the fact that the bottom of the rudder is flat. A rudder with more profiling to it might be a little more difficult.

Putting it simply - get the right bearings, and make sure your alignment is good.