[Rhodes22-list] How bad is my CB plate?

Sat Jan 17 22:52:49 EST 2015

Hi Brooks:

If the damage is limited and the holes are not already too large to be
re-drilled, then I would go with the advice of Chris Greco. However, if the
cap and the trunk flange is too damaged then something more dramatic might
be necessary. From the pictures, it looks like the screws were already
replaced with bolts. I also think it would be difficult to do that much
damage with screws alone. I worry that the damage to the cap might also have
resulted in damage to the trunk flange and that would make me wonder whether
bolt replacement would be sufficient. 

I can only tell you what I did when faced with a badly damaged cap and
trunk.

You need both the cap and trunk flanges to be flat, smooth and strong to
create a watertight join. 

First, I would be inclined to use a grinder to remove any of the damaged
parts of the cap and repair using several layers of cloth and epoxy - much
stronger than polyester resin - and then fair it off using epoxy and fairing
filler such as 407 low density filler. I would build up and strengthen the
top side of the flanges by grinding it smooth and then laying on three of
four layers of cloth in concentric circles for several inches around the
bolt holes. You want the areas around the holes, which will need to be
re-drilled,  to be particularly strong. 

This step gives you a strong repair but it does not give you the
sufficiently flat and smooth surface that you need for a watertight join. 

When I had to repair my badly damaged cap and trunk I used West System epoxy
with 406  Colloidal Silica filler to make smooth and flat surfaces for both
the trunk and cap flanges. After cleaning the cap flange and sanding it with
150 grit sandpaper, I put a generous layer of the mixture made to the
consistency of mayonnaise on the bottom of the cap flange and then clamped
it to a flat surface like 3/4 inch MDF board using waxed paper or plastic
sheeting as a barrier so the mixture did not bond the cap to the board
permanently. Be careful to ensure that the barrier material does not have
any wrinkles in it. The clamping should ensure that the cap is flat and the
mixture spreads but does not need to be excessive.  I clamped the cap down
to make sure the epoxy mix spread out over the entire surface of the cap and
filled the voids. 

Once the epoxy set, but before it cured, I removed the clamps, peeled off
the waxed paper and trimmed off any of the filler that extended beyond the
flange. You can do the same thing on the trunk side if it is damaged at all.
Now you will have two flat and smooth mating surfaces for sealing.

If you have not used epoxy and fillers before I suggest that you experiment
a bit so that you get a feel for its working time and characteristics. When
the epoxy first goes off it loses its tackiness in a few hours or less but
it is still soft enough to scratch with your fingernail. At this point you
can remove the barrier sheet and trim the edges of the flange with a sharp
razor knife fairly easily. Once epoxy cures it is very hard and to trim will
probably require the use of a grinder.

Replace the gasket and gradually bolt the cap to the trunk working in a
pattern out from the centre. You do not need or want to crank the bolds down
too tightly - just enough that the gasket is compressed. Over tightening
will distort the match and, as you are aware, damage the fibreglass around
the holes. I also used washers to spread the load at the holes.

All of this might seem daunting if you have not used epoxy but it wasn't all
that difficult.

Alternatively, take the boat back to the yard that did the work and tell
them to do the job properly.

Graham 

-----Original Message-----
From: rhodes22-list-bounces at rhodes22.org
[mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of The Rhodes 22 Email
List
Sent: January-17-15 8:19 PM
To: rhodes22-list at rhodes22.org
Subject: [Rhodes22-list] How bad is my CB plate?

My "new" 1986/2006 had recent CB work done by marina in CN. They were
supposed to test it in water. I launched boat after bringing it home, sailed
it and put it away for night. Next morning, bow was down a foot. After
bailing, a  friend noticed some of bolts on CB were not tight, causing the
leakage. After tightening, most of leak disappeared but just kept leaking
like a quart a day. Several rounds of tightening did not cure leak and I
stopped, fearing damaging CB plate. 

Now, several weeks after taking it out of water, I've removed  the CB plate
and I'm not liking what I'm seeing - appears I should have stopped
tightening sooner.

I've enclosed 3 pictures, 1 of trunk, 2 of plate - part that seals against
rubber.

The worst places on plate are near the 1.5 " slot in trunk for the knobs (?)
on CB to slide up and down. The FG between bolt hole and slot is very thin
and has been damaged - creates a small recessed area rubber might have a
problem sealing.

My other concern is that the plate is now deformed at each bolt hole and
there are stress cracks, some which look like they could let water in.

I'm considering prepping area and trying to put down some FG resin to seal
recessed area and small stress cracks.

So, if you are knowledgeable about this, please take a look at photos let me
know your recommendations.

<http://rhodes-22.1065344.n5.nabble.com/file/n49315/IMG_1436.jpg>
<http://rhodes-22.1065344.n5.nabble.com/file/n49315/IMG_1441.jpg>
<http://rhodes-22.1065344.n5.nabble.com/file/n49315/IMG_1432.jpg> 

Brooks Bridges
1986/2006 Rhodes 22
Cambridge, MD

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