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Author Topic: Rudder blisters  (Read 138 times)

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ChrisOB

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Rudder blisters
« on: December 03, 2019, 04:12:00 PM »

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 donít see any recent posts on the topic so thought Iíd 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
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1986 MK1 Tall rig/Fin Keel #247

ChrisOB

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Re: Rudder blisters
« Reply #1 on: December 03, 2019, 07:38:37 PM »

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? Iím having trouble finding the layup of the rudder, I assume there is foam behind this hard white layer.
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Noah

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Re: Rudder blisters
« Reply #2 on: December 03, 2019, 08:03:10 PM »

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.
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1990 hull #1014, San Diego, CA,  Fin Keel,
Standard Rig

ChrisOB

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Re: Rudder blisters
« Reply #3 on: December 03, 2019, 09:19:37 PM »

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 Iím seeing is Gelcoat on the rudder.  Said to sand and epoxy with fairing thickener (easy to sand compared to silicia etc).  So thatís 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)?
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Noah

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Re: Rudder blisters
« Reply #4 on: December 03, 2019, 10:06:26 PM »

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.
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1990 hull #1014, San Diego, CA,  Fin Keel,
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ChrisOB

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Re: Rudder blisters
« Reply #5 on: December 03, 2019, 11:03:12 PM »

Ok

#2- think anyone has done this without dropping rudder? My emergency tiller cap is stuck on there, and Iíd have to remove quadrant and Edson bronze tiller for below deck autopilot.  And Iíd 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 donít 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 donít want to go jamming things down there that I canít get out either...
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Noah

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Re: Rudder blisters
« Reply #6 on: December 04, 2019, 09:46:03 AM »

Sorry, I canít 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.
« Last Edit: December 04, 2019, 10:08:26 AM by Noah »
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lazybone

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Re: Rudder blisters
« Reply #7 on: December 04, 2019, 11:27:04 AM »

The rust stains (structural issue) should be your biggest concern.  The rest is fluff.
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S/V LAZYBONES  #677

ChrisOB

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Re: Rudder blisters
« Reply #8 on: December 04, 2019, 08:48:41 PM »

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! 
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Noah

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Re: Rudder blisters
« Reply #9 on: December 04, 2019, 10:46:00 PM »

IMOóThe 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, whatís causing it?
« Last Edit: December 04, 2019, 10:46:46 PM by Noah »
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