[C320-list] Strange coating

[Michael Leschisin]

Hey Charlie,

Are you sure you have blisters?  I also use VC-17 and each fall when I pull the boat there are little “bubbles” of water here and there under the bottom paint.  They resemble blisters but are really just pocket of water being held between the hull and the paint.   

A few years ago I had one of the boat techs at our yard take a look and he said it is simply failure of the paint to adhere to the hull due to poor bottom prep on the original paint job.  Could be a matter of not fully removing the mold release materials or something.  I find these bubbles tend to disappear or at least are reduced once the boat is out of the water for a couple of weeks.  

You may already know this, but blisters are caused by water intrusion behind the gel coat and into the structural fiberglass of the hull.  They are generally seen as raised areas on the gel coat, sometimes with a pin hole in the middle where the water originally seeped in.  If your gel coat isn’t raised, I doubt you have blisters.  If you can, try to gently remove the bottom paint (maybe with a plastic razor blade) without disturbing the gel coat in the area of a few of your “blisters”.   You should be able to determine if the gel coat has a bump on it and you truly have blisters or it is simply paint failure going on as I have.  Each season I end up chasing a few dozen of these bubbles.  A moderate power washing tends to knock them off when I first come out of the water in the Fall.  I give the white spot where the hull is now showing through a very light sanding and a quick wipe with acetone in the spring before I do my bottom paint.  That tends to keep each one from returning.  I’m making progress but there are always a few popping up here and there each season.  It’s a bandaid approach but I’m saving fully stripping and cleaning the bottom for the days when I’m retired.  (Somebody told me I’d have more time then)  I’ll probably also do a full E2000 or Pettit Protects job with the hope of sailing over the horizon, into the salty water to lands of coconuts and palm trees.  - I’m sick of winter in the Midwest already!

Good luck with it,


Michael Leschisin

Wild Blue Yonder
C320 995
Menominee, MI

> On Jan 6, 2023, at 3:14 AM, Charles Holbrook <charlesholbrook at ymail.com> wrote:
> 
>  Thanks Chuck!
>    On Thursday, January 5, 2023 at 06:10:53 PM EST, Chuck Mueller <katchu at chartermi.net> wrote:  
> 
> Charles – It’s probably a good idea to use some sort of barrier coat if you are sanding off blisters.  Otherwise you just get moisture back into the fiberglass and a new blister emerges.  Interprotect 2000 and Pettit Protect are two good choices.  Expensive, but they work really well.  Put on a few costs before overcoating with VC-17
> 
> Chuck Mueller
> Northwind #676
> Holland, MI
> 
> 
> Message: 3
> Date: Thu, 5 Jan 2023 20:36:22 +0000 (UTC)
> From: Charles Holbrook <charlesholbrook at ymail.com>
> To: "C320-List at Catalina320.com" <C320-List at Catalina320.com>
> Subject: Re: [C320-list] Strange coating
> Message-ID: <82570557.3099923.1672950982925 at mail.yahoo.com>
> Content-Type: text/plain; charset=UTF-8
> 
> Het Chuck and Michael:
> I too am a freshwater C320 in Lake Erie.? Annually, I treat the bottom with VC 17.? Sometimes I need to sand a blister here and there but have never treated the bottom with anything but VC 17.? I have had the boat for 7 years and have never done any bottom treatment but VC 17 right over top of the sanded areas. Should I be painting the bottom on the spots I have sanded off???
> Charlie
>     On Thursday, January 5, 2023 at 10:58:54 AM EST, Michael Leschisin <mleschisin at imagestudios.com> wrote:  
> 
> 
>