Rudder blisters

[ChrisOB]

This was the first year in my 7 year ownership where the boat stayed in the water for more than 8 months (it was just hauled after 16 months since last haul).  I was wet sanding the bottom and found maybe 50 blisters on the rudder, most are the size of a pencil eraser.  If I pick at them I get down to a hard white material below layers of paint and gray (barrier coat?).  I also have had the rusty rudder stain from the post for a while.  I know don't see any recent posts on the topic so thought I'd ask advice.  It sounds like Catalina does not do the recast anymore, so I will have to fix.  I also have some play in the rudder bushing.  I saw the 2 fixes as sliding plastic sheets down there or dropping rudder and waxing and filling with epoxy.  I may not be able to drop rudder at this yard. 
Thanks

[ChrisOB]

To make the question more specific, does anyone know what the hard white material I was able to get down to with my knife is? It looks clean and hard, is it possible the blisters were just in the paint and barrier coat? I'm having trouble finding the layup of the rudder, I assume there is foam behind this hard white layer.

[Noah]

Osmotic blisters in gelcoat will emit a smelly acid-like liquid (oder of styrene and vinegar) when popped. Unfortunately, blisters are best located/popped (and then rinsed with fresh water) right after hauling or they may shrink back and be undetected.  The hard white surface may be the gelcoat. Epoxy barrier coat is usually some sort of color. Your blisters could be Just in the bottom paint not gelcoat.

[ChrisOB]

I had a neighbor in the yard take a look and he thought the blisters were in the paint and the fairing and the white I'm seeing is Gelcoat on the rudder.  Said to sand and epoxy with fairing thickener (easy to sand compared to silicia etc).  So that's good, I guess.  Any thoughts on the play in the rudder bushing? Any new techniques besides the 2 I have found (plastic sheets, vs drop rudder, wax shaft, fill with epoxy)?

[Noah]

Seems like you have possibly at least three issue going on,
1. Blisters
2. Rudder sloppy/in tube
3. Rust stains

Fix for #1 is sand, fair and paint
Fix for #2 may be:
https://www.catalinadirect.com/shop-by-boat/capri-25/hull-deck/stern/rudder-bearing-epoxy-repair-kit/?SearchResults=1

Fix for #3 is drill drain holes at the bottom to drain the water then open it to explore what is rusting.
Fix it and bad metal and then re-fiberglass it over.

[ChrisOB]

Ok

#2- think anyone has done this without dropping rudder? My emergency tiller cap is stuck on there, and I'd have to remove quadrant and Edson bronze tiller for below deck autopilot.  And I'd also have to bring the travel lift over and hang in the slings to do this as I cannot dig a hole here.  I also don't want to epoxy my rudder into place....  I believe Ron was a big believer in the plastic/Mylar sheets slid down below the emergency tiller cap to fill the gap.  Heard of anyone else doing that successfully?  I don't want to go jamming things down there that I can't get out either...

[Noah]

Sorry, I can't help you with the rudder bearing questions. You can drill and carve rudder to inspect rusting grid and drain water and repair fiberglass, with it still hung/mounted, I believe. I feel your pain about removing rudder and dread the day when I have to drop mine, as I too have a below deck autopilot attached. As far as the emergency rudder cap; split it with a cold chisel or cut it with a grinder to remove, and replace with a new SS from Catalina Direct.

[lazybone]

The rust stains (structural issue) should be your biggest concern.  The rest is fluff.

[ChrisOB]

Lazy bone:

Re: rust stain

Do you feel the rust stain is an indicator of a compromised rudder?
Compromised shaft to rudder joint?

I drilled 3 small inspection holes in the lower part of the rudder and the foam was bone dry.

If the blisters are fluff compared to the rust can you elaborate what is wrong and how to fix?

I was personally more concerned with the blisters than the rust drips.

Thanks! 

[Noah]

IMO—The concern would be the internal steel grid and and its connections to the rudder post could be compromised and fail due to water intrusion. However, if you drilled several holes in the bottom of the rudder and no water drained out...it is a head scratcher. Where is the rust coming from, what's causing it?

[Ron Hill]

Chris : I'll guess that your rust stains are coming from the top were the stainless column enters the rudder layup!! That's why I poured some of the "Gulvit" into the center and then later sealed around outside where the column enters the layup. 
You need to drill A HOLE OR TWO IN THE MIDDLE OF THE RUDDER, JUST AFT OF WHERE THE COLUMN IS. That is the grid location.

A few thoughts

[ChrisOB]

The rust is coming from a crack in the layup I discovered at the lower part of the rudder post, where the rudder forms a right angle and extends forward.  I hit a big partially submerged log a few years ago, that may have been what caused the crack.   I ground the crack out a bit and a little more water is coming out.  I also cut the old aluminum emergency tiller cap off and can see some wet gunk down in the bottom.  I guess I should drill some more holes closer to the shaft for a core sample there.  Also, when water gets on the tiller cap, the through bolt is not waterproof, if that water gets down the shaft where is it supposed to go?  I’m not positive what the prognosis is at the moment or what to focus on next.  I could potentially remove all my below deck AP stuff and have them move to to a spot where I can fully drop the rudder, but not sure what that is gaining me at the moment.  Thanks for all your input.

[ChrisOB]

Update: I sanded the whole rudder down and epoxied the dried out blisters and then did 3 barrier coats.  Also ground out around the other problem areas and epoxied.  I successfully executed the graphite pad injection method to remove the slop in the rudder tube, it has zero play now, moderately difficult using epoxy graphite in a caulk gun while down in the aft lazarette.  No issue getting the rudder back out, I waxed it with regular collonite before the epoxy and let it set for 2 days.   I now have 12 black graphite pads around 3" each that the rudder stock rides on. Tef gel on everything so will be easy to drop rudder if I ever have to again.

[scgunner]

Chris,

What I've found over the years is the bottom paint on the rudder gets hit particularly hard. For one reason is it's exposure to the sun, on my boat I generally get most blistering on the sunside water line and the rudder. Also the bottom cleaning process is hard on the paint especially on the edges. I found extra paint in those helps keep the boat in the water longer between haul outs. I generally put 5 or 6 coats on the rudder depending on how much time I have and how much paint I have left.

On the rudder slop I used the West System epoxy graphite injection process, that was over 20 years ago, it's still tight.