Rudder problem resolved
Phil May and Andrea Twigg
Wed 26 Nov 2014 16:56
Andrea just mentioned that the scabs have started falling off her legs, which reminds me that the Bonaire blog did not do justice to her epic struggle with the rudders in Bonaire.
On the way over to Bonaire we discovered that the rudders were in a bad way. The steering was so stiff that it was hard to turn the wheel at all. This amount of force on the wheel must have been placing huge stresses on the steering linkage. (With a catamaran the linkage between the rudders is driven even when using the autohelm.) I ended up hand steering, reducing the load by applying limited turning force and then waiting for wave action to kick the rudders around.
We could not cross the Caribbean with the steering in that state. There was no alternative but to drop the rudders in Bonaire and see what was up with the bearings. I was concerned that the shafts (newly machined in Fort Pierce to get rid of the horrible clunking noises they were making before) had developed some severe corrosion which might result in a lock-up.
Decoupling the rudder linkage is simple, but we then had the devil of a job getting the rudders out. We even tried tying a big bag of rocks to the shaft, to apply a greater downward force, but it just got in the way. (We were also a bit concerned that, while the rudders normally float, they don’t with rocks attached and we were moored over a drop-off of unknown depth).
In the end it took half an hour of my standing on the top of the rudder stock, with Andrea in the water kicking the rudder from each side of the hull, to get one of them out. (Andrea preferred to do the kicking rather than the standing, but she did get little scrapes on her legs, hence the scabs now falling off.)
Once removed, the shaft was fortunately not corroded. Apparently the problem was just that the Delrin bearings absorb moisture over time and this swelling had caused them to grip the shaft like a vice.
I polished the shaft with 300 grade wet and dry paper to remove a fraction of a millimetre of the aluminium. Then it was back into the water for both of us, to re-insert the rudders in the bearings. Which was challenging, but nothing like as difficult as removing them was.
Now you can spin the wheel with one finger. (Or two fingers crossed.)