Rudder bearings - how much play is too much?

[[2574]]

My boat has a skeg hung rudder and is about 1.5m deep (at a guess) see here:

It is possible to feel lateral movement of the rudder by pushing the blade side to side, difficult to estimate how much and I haven't attempted to measure it. But I can feel movement. How much movement is indicative of knackered rudder bearings? There is no "tightness" to the helm nor any feeling or sound of looseness when sailing. I think I might be imagining an issue that doesn't exist - unless the usual erudition hereabouts thinks otherwise?

TIA

Rob

 

[RichardS]

I can feel lateral movement on both my rudders. Possibly a mm or so which gives a quiet clonk when moved briskly.

I can'e see any problem with this and would rather that than the bearing tightening up and being impossible to turn which we have also suffered.

Richard

 

[vyv_cox]

I have owned my boat for nearly 25 years and it has always had detectable play in the upper bearing, perhaps a little more than 1 mm. This has never been a problem. A few seasons ago we began to sense that there was a rudder problem, with increased fluttering felt as water flowed over it, both under sail and motoring. Inspection at the end of the season showed the lower bearing to be quite worn. Full story at http://coxeng.co.uk/stern-gear/sadler-34-rudder-bearings/. Since replacing the lower bearing the feel of the rudder has reverted to its previous condition. The play in the upper bearing is as it was, no problem.

 

[PuffTheMagicDragon]

As long as you don't have excessive vibration it's not really a problem, especially at 'sailing speeds'.
When I removed the rudder from the skeg during the process of replacing the old epoxy treatment I noticed that the bearing that was in the bottom 'cup' (I don't know what you call it in English; We know it as the 'shoe') was quite worn. Rather than digging out the old bearing and machining a new one I simply added a 'liner' that happened to fit well on the lower pintle. The source was the bottom part of an old plastic container for a 35mm film (remember them?) cut to a suitable length. Cheap and effective.
You could source an offcut from a piece of plastic drain pipe that has a suitable bore but, unless there is excessive vibration I would just leave it well alone.

 

[[2574]]

Thanks all - I’m not going to worry about it. Leave well alone sounds like good advice to me.

 

[Neil_Y]

You need clearance in plain bearings so you will have movement.

As a very rough guide 50mm shaft in a 70mm carrier new (our min) clearance at the bearing is 0.20mm if you do some maths or draw a diagram with length of rudder from bearing as a pivot, at the bottom of the rudder it can quite easily be a mm or two lateral movement.