Upper Rudder Bearing Scantlings

[Bill Bowers]

I am overhauling the Whitlock Cobra Premier pedestal assembly on J42 #3 ConverJence to include new bearings, rose joints and strip/prime/powder coating the pedestal rectangular post.

Noting the USSailing Incident reports from 2024 NBR regarding upper rudder bearing issues with Alliance (sunk after upper bearing torn out of its mount) and Ceilidh (had to add 4 screws to prevent bearing shifting).  These are both newer open transom J boats with upper bearings in the cockpoit sole very close to the lower bearing.  The lessons learned included need to eliminate or avoid the common ~1/8” clearance between the hole in the composite and the outer wall of the upper bearing, thereby placing all the side loads on just the bolts thru the composite.

The photo shows that our bearing has that gap and is indeed just supported by the cured bedding compound and 8 throughbolts. The glass side wall of the bearing pocket is 1/4” thick.  

The good news is the ghenerous 30’” spacing between the upper and lower bearings provides far more support than the open transom boats.

As the lower and upper bearings of the ruddser have no play and turn smoothly I am inclined to not drop, tear out, reinforce and rebed the upper bearings at this point.

Has anyone heard of problems with any after deck J4x upper bearings attributed to open space around the bearing?

[Todd Stevens]

Not exactly sure of the arrangement on a J/120, but I thought that the report on Alliance was strikingly similar to what happened to J/World in 2009. I don’t recall that they had time to examine the upper bearing, but it was thrashing around loose.  I was under the impression that it was our kind of poop-deck arrangement because IIRC one of the first signs was that the engine panel was punched out into the footwell.  But in both cases, I think the hull was ruptured too. Keeping the bearing in place might help stop the rudder from thrashing around, but IDK if it would have helped either of those boats stay afloat.

I have thought more than once about trying to wall that aft lazarette off from the rest of the boat.  

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[ankg...@gmail.com]

‘Wall off the aft compartment from the rest of the boat’: Yes! Why is it that we’re not doing that? Seems obvious, doesn’t it? There are a few details to work out:

 

1. How to run the engine exhaust
2. How to clear the steering cables
3. How to drain the compartment if there’s any water collecting from rain or the lower bearing.

 

Maybe we just install temporary barriers that we can put in place for blue water races such as NBR etc?

 

Al Goethe

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