stainless rudder tube issues.

[moodyfinn]

Hi All, after deciding to service the rudder assembly on my swan 53, which should be straight forward as long as you don’t mind dancing around the yard with an 11ft 150kg totally unbalanced rudder, i have found some issues which have exhausted my immediate knowledge to repair. On removing the rudder i noticed the bottom lip seal was almost popped out and the seal retaining ring was loose and packed with a 5200 type mastic. the six screws which hold the retaining plate may as well not be there as the threads were non existent.
i can overcome this by drilling and tapping new holes, tricky but doable on the boat.
The rudder shaft and bearing faces all seemed okay so it was deemed a good clean up, new seals and a couple of plastic washers should see me good for another 10 years……..or maybe not! Before fitting all the bearings and seals onto the shaft I wanted to know how easy it was to fit the new bottom seal as the last person clearly had issues. The seal is a 105 x 120 x 10 standard nitrile seal with spring. could i get the seal in? No, it was too big. i could have used force but not really good practice. The rebate for the seal measured 118.7mm which is way too small for that seal. Data and drawings state the seal should be 120 and the tolerance is absolute 120mm recess for that seal. So, either my bearing housing has shrunk or this has been an issue since new.
if i could buy a seal to fit then i would but none available so i’m left with the only option which is to remove the whole tube assembly and get it re-machined and new retaining ring threads cut.
I can take it out, but it passes through a strengthened area of about 25cm of what appears to be solid fibreglass. when i put the assembly back in, what compound would be used to bond, seal, support the tube between the stainless and fibreglass. There is a top bearing about 30cm up from the top of the lower bearing tube so loading is not extremely heavy but need to be adequate, whatever that is! The bottom of the tube has a hefty fabricated bracket which is secured by 6 x M14 bolts through a rear facing vertical panel. I suspect this is the strength in the assembly and will locate the tube where it should be, with all the normal alignment checks of course.
Has anyone done this removal or has anyone got any ideas on securing once in place.
it’s also just my luck that its midsummer in finland so nobody is at work until the hangovers are cured!

[moodyfinn]

photo of tech drawing