We’ve just finished a complete rebuild of the steering system on our Aloha 32. When we purchased the boat in November 2005, we noticed about 1/8″ play in the top rudder bearing. After hauling the boat, we also noticed about 1/16″ play in the bottom bearing.
Upon pulling the engine for repair, we found about 1/2 gallon of sandy sludge on top of the quadrant, on the hull around the rudder post, under the fuel tank and engine, and on down into the bilge.
We disassembled the steering system to investigate. I’ll describe the construction of the steering system in detail, because I think it will help in discussing the problems and the solutions we chose:
As built, the rudder shaft is a 1 7/8″ OD stainless tube. Near the top of the shaft is a 1/2″ diameter stainless pin inserted through the diameter of the shaft. Under this are two 4″ diameter, 1/2″ thick aluminum disks. The 1/2″ rod is secured to the upper disk with a stainless machine screw. The lower disk rides on a plastic bushing which looks a bit like an inverted top hat.
A 1″ deep drain well extends across the width of the cockpit sole with drains in the outboard corners. The “brim” of the rudder bushing rests on the floor of this well at the center, with the tubular part extending down through a hole in the floor of the drain well. The “brim” of the bushing is secured to the drain well floor with three 1/2″ flat-head wood screws.
We found that the bushing, and thus the entire shaft assembly, was moving laterally at least 1/8″ inch when under load. The bushing was also rotating about +/- 10 degrees when the rudder shaft rotated. The screw holes were elongated, so the screws were no longer doing their job, and in fact their heads were gouging out the bottom of the lower aluminum disk.
It’s clear that the sand and grit, carried by water from the cockpit sole, migrated underneath the bushing, onto the quadrant, and thus down into the bilge. In fact, the sand underneath the rotating bushing milled down through the fiberglass into the plywood.
Our lower rudder bearing is a simple fiberglass tube. Over the 22 years since our boat was built, the rudder shaft was worn down about .003″ in diameter (as compared to the unworn parts of the shaft). The tube was about .060″ larger in diameter than the shaft.
Unlike some other sailboats, there is no packing gland at the top of the rudder tube. The top of the tube appears to be somewhere between 3″ to 5″ above the static water line, so when the boat was new, the close fit between the tube and the rudder shaft presumably kept the water out, even when under way.
It’s interesting to note that another Aloha 32 owner recently reported leaking from the front of his rudder tube at high propeller speeds. We only had a few hours on our boat before we hauled it for refitting, so we didn’t observe any leaking. (But with the mess in the aft space of our boat, it might have been difficult to see in any case.)
The quadrant on our Aloha 32 is actually a complete wheel, and is clamped with several bolts, and secured from rotating with a pinning bolt through the shaft. When we removed the quadrant (luckily it was easier for us than for you), we found the bottom of the quadrant severely eroded, to the point where the pinning bolt was exposed over most of its length. The rim was also quite rough from corrosion.
Since the quadrant was mounted only about 1/8″ above the top of the rudder tube, one imagines that water splashed up the rudder tube onto the bottom of the quadrant from time to time. The quadrant, being aluminum and anodic with respect to the stainless shaft, eroded away.
Here’s what we did to solve the various problems:
Bottom Bearing
After considerable research, we decided to rebuild the bearing surface by injecting graphite-loaded epoxy into the rudder tube, using the rudder stock as a mold. This method is described in section 8.4 of “Fiberglass Boat Repair & Maintenance”, published by West System Inc.
In short, the technique is to remove the rudder, drill several holes into the rudder tube, reinsert the rudder, then use a syringe to pump graphite-loaded epoxy through the holes into the gap between the rudder stock and the rudder tube.
To begin, we dropped the rudder and cleaned up the shaft with coarse emery paper. We especially concentrated on working down the unworn parts of the shaft to try to eliminate the .003″ step worn by the rudder tube. We were concerned that since the new bearing diameter would be based on the lower, worn part of the shaft, the upper, unworn part of the shaft might not fit through the bearing when we needed to remove and reinsert the rudder.
Next, we drilled four holes in the skeg from outside the hull, diagonal to the boat’s centerline, and parallel with the waterline. We originally hoped to find solid fiberglass here, but we found an air gap between the skeg and the rudder tube. While it might be possible to fill this gap with a low-viscosity epoxy, we decided to simply find a syringe with a longer nose. We ended up drilling 1/4″ holes right through the rudder tube, and 3/8″ clearance holes in the skeg to provide clearance for the syringe nose.
We then applied two coats of mold-release wax to the rudder stock and inserted the stock into the rudder tube, blocking the shaft so it was approximately centered in the tube.
Following the instructions in the West System book, we created a 50/50 mixture of graphite powder and colloidal silica. (The graphite power adds strength, hardness, and lubrication to the completed bearing surface; the colloidal silica is a thickening agent.) We added this mixture to some System Three epoxy to get a mayonnaise consistency, and loaded the result into a syringe.
The West System instructions suggest injecting only enough epoxy to form 1″ diameter pads inside the rudder tube. We instead injected enough epoxy to form a 2″ to 4″ band all around the tube, since we wanted to form a barrier to water coming up the tube. Using a bit of simple geometry, we determined that 20 ml should be about right, so we injected about 5 to 7 ml into each of the four holes.
It’s important that the syringe fit tightly into the hole in the rudder tube, since you need to apply significant pressure to get the epoxy to flow inside the tube. We had one hole that didn’t fit well, so the epoxy squeezed out past the syringe. The resulting bearing surface at that point was only about 2″ high, rather than the 4″ of the rest of the bearing. Next time, I’d epoxy the bad hole and re-drill to get a better fit before injecting.
While injecting, we could tell that the epoxy was flowing as desired, and that our calculations were correct, because we could see the epoxy show up at the holes on either side of the first holes we injected into.
We let the epoxy cure for about eight hours, then turned the rudder to break it free, and then came back every few hours to break it free again. We left the rudder in position for about a week to ensure the epoxy was completely set. We wanted to avoid damaging the new bearing surface when we dropped the rudder for the rest of the required repairs.
Top Bearing
While the bottom bearing was curing, we set to work on the top bearing. Since we had hammered pretty hard on the top of the rudder shaft to get the aluminum disks off, the floor of the drain well, which was already damaged by the sand milling away the fiberglass, was now delaminated as well. To begin the repair, we ground away the loose fiberglass and wet wood over an area about 8″ square. We then used System Three RotFix (a penetrating epoxy) to stabilize the wood and secure the remaining fiberglass to the wood. Finally, we laminated back up to the original thickness with epoxy and glass cloth.
We wanted to make sure that any water and grit in the drain well would drain away from the rudder bearing in the future, so we added a 1/2″ thick plywood land under the rudder bearing, beveling the edges and glassing it over. On reassembly, we omitted one of the two 1/2″ thick aluminum disks to maintain the original rudder shaft height.
We eliminated the possibility of water in the plywood by drilling the hole for the bushing about 1/4″ oversize, which allowed space to pack in epoxy loaded with milled fiber around the bushing.
To ensure a really accurate fit of the epoxy around the bushing, we used the bushing itself as a mold. We first applied a generous coat of mold-release wax to the bushing, then we dropped the rudder a few inches, inverted the bushing and put it on the shaft. We raised the rudder back into position, pushed the bushing up until it met the bottom of the drain well, and secured
it there with duct tape. It was then possible to pack in the epoxy and milled fiber around the bushing. We let the epoxy cure well, then removed the bushing.
Once the hole was cleaned out and the bushing reinserted from the top, it was perfectly aligned with the shaft and had absolutely no slop whatsoever. Finally, we drilled for the bushing retaining screws. Again, we avoided any future water ingress by drilling a bit oversized, packing the holes with epoxy and milled fiber, and re-drilling for the screws after the epoxy cured.
Quadrant
Even though the rebuilt bottom bearing should exclude water for some years, we wanted to avoid having to replace the quadrant ever again.
The Edson radial drive wheel used on the Aloha 32 is shaped like a shallow dish, with a hub on the bottom of the dish. As built, the wheel is mounted dish up, with the hub below. After much careful measuring, we determined that there is enough vertical space below the drain well to mount the quadrant upside-down. The inverted position puts the hub above, with the
dish facing down.
According to the Edson manual, this mounting arrangement is completely acceptable, as long as the cable runs true onto the rim of the wheel. Mounted in this way, the quadrant is several inches above the top of the rudder tube, so that any small amount of water which may intrude will not be able to reach it. Another advantage is that the quadrant clamping bolts are now on the top, so are easily accessible from the lazarette for the next time we need to drop the rudder.
Final Assembly
When reassembling the steering system, we lubricated both the upper and lower shaft bearings, the idler bearings, and the steering wheel bearings with Teflon grease. On the advice of our mechanic, we also lubricated all bolts and the quadrant-to-shaft interface with the same grease, to help avoid avoid them seizing in the future.
With a new cable assembly, a complete re-bedding of the steering column, and a bit of paint, we figure that with a little luck we’re now ready for another twenty years!
Written by David Querbach