[C320-list] Peeling Bottom Paint

[Chris Descher]

I've got hull #500 and have just gotten her back in the water after her
first bottom job since she was commissioned 12 years ago.

Soda blasting was not an option at the yard.  They sand blasted.  Before
this, the boat was power washed, and no blisters showed.  Three weeks later,
after sand blasting, not very deeply, we, too, found blisters in the areas
you mentioned, around the prop strut and on the hull above the keel, but
most of the blisters we found were on the sides of the keel.  Some of these
on the keel had popped, but most of them hadn't.  We had the yard repair all
the blisters that had opened on the keel plus all of them on the hull.  I
don't know if it was a bad idea or not, but we left alone the blisters on
the keel that hadn't popped.

It won't be 12 years before our next bottom job.  Maybe we'll deal with them
then.

Chris Descher

-----Original Message-----
From: c320-list-bounces at lists.catalina320.com
[mailto:c320-list-bounces at lists.catalina320.com]On Behalf Of Charles
Greenwell
Sent: Thursday, June 03, 2010 9:38 AM
To: c320-list at lists.catalina320.com
Subject: Re: [C320-list] Peeling Bottom Paint


Thanks for all of the suggestions. Here is what I found and how I
repaired.

I sanded out the patch areas around the strut and shaft alley opening.
After 3 days with heat lamps the moister meter reads 0. I then applied
Interlux Watertight epoxy filler, feathering it with the gel coat. I
will sand these areas tonight and apply Interlux 2000E barrier paint.
When I am ready to apply the bottom paint, I will apply a second coat of
barrier paint.

In talking with the factory, apparently when the strut and shaft alley
are installed they mask off a square area around them on the hull, then
fill and gel coat the area feathering in the strut and shaft alley. It
is this area that blistered not the hull itself.  Some of the blisters
were as big as silver dollars with so many smaller (1/4 in) ones it did
not make sense to repair them, it was easier just to sand the whole are
down and start anew.

The wet area aft of the keel is a little more problematic.  I sanded the
gel coat away in a 10x24 area exposing the wet area. After 3 days with
heat lamps, the area still reads a little moister, about 1/10 of the
initial reading on the meter.  This area appears to be the edge of where
the keel was faired to the hull. Once the meter reads 0 I will apply new
gel coat and barrier paint.

My boat is 10 years old.  Based on this experience, I would suggest that
everyone with older boats take a close look at the shaft alley and strut
areas when they haul out the next time. Prior to soda blasting, I did
not know that there was a problem, these areas looked OK to the naked
eye. Just food for thought.

Randy
Le Bijou
Hull 719