Chain Plate Leak Repair
I had a problem with the middle stanchion on the port side.
The following is plagiarized from this forum (be glad to give credit to the
original author...if I remembered who it was) :
1.. Move your cushions far away from the big mess you are about
to make and also get the table out of your way. Place some rags or an old towel
under the work area.
2.. Remove the shroud.
3.. Remove the strut. Remember the sequence and
position of the spacer and washers at the bottom of the strut. Mark the spacer
so you know which side is up. A crows-foot socket makes loosening (and
tightening) the nuts on the bottom of the strut a little easier. The strut
holds a bit of tension between the deck and the beam that is built into the
liner. Notice how many turns it takes before the upper nut on the bottom of the
strut comes loose and releases that tension. This will help when you reinstall
and re-tension the strut. Typically the nut will come loose after about 1 1/2
turns.
4.. Remove the 4 Phillips head thru-bolts. The
threads may be galled so you might need to purchase new ones, 1/4 x 20 x 1.5”.
5.. Remove the tang (step on it).
6.. Mask the deck around the trim plate so
clean-up after caulking is a little easier.
7.. Pry the trim plate off of the deck.
8.. The hole in the deck is larger than the
tang and is filled with caulk. Clean out
all of the old caulk.
9.. If the deck has a wooden core, clean out
any rotten wood, let the core dry and fill the void with an appropriate filler.
10.. Clean the deck and cabin liner surfaces
with a razor scraper, gasket scraper, Dremel tool, wire brush or any other
suitable tool, and wipe them down with acetone.
11.. Use a chamfering bit to lightly chamfer
the screw holes and a file to chamfer the larger hole.
12.. Install the tang with the 4 screws but
without the trim plate. You don’t need to use any caulk on the underside of the
tang. If the topside is sealed there doesn't seem to be any purpose to it. If
the topside seal breaks, the underside caulking might keep some water out of
the boat, but it
might also mask the problem while your deck rots.
13.. Fill the space around the tang with Boat
Life’s Life-Calk and let it cure overnight. Life-Calk is available in caulk gun
tubes which are easier to use than the smaller squeeze tubes when filling a
large area.
14.. Trim the
dried caulk around the tang so that it is flush with the deck.
15.. Remove the Phillips bolts.
16.. Put a heavy bead of caulk around the tang.
17.. Put some caulk in each bolt hole.
18.. Put a bead of caulk on the deck around
each bolt hole.
19.. Carefully place the trim plate in
position. Use a couple of bolts to align it as you press it down firmly and
force the caulk up between the plate and the tang.
20.. Put some caulk under the head of each bolt
and push the bolts into the holes while pulling up on the tang. Don't push the
tang down and ruin the seal.
21.. Tighten the 4 bolts. It would help to have
someone on hand to assist with this step but it can be managed without
assistance.
22.. Clean up the caulk and remove the tape.
23.. Attach the strut. Hand
tighten the upper nut until snug, and then use a wrench to tighten it
approximately another 1 1/2 turns.
24.. Attach the shroud.
For those to timid to attack a
leaking chain plate, here is what I found. The prepurchase
survey reported moisture in the center chain plate port and starboard.
I removed the shrouds from the
plate. There is simply no other way. Mark the threads with tape then back off
the adjuster counting the turns. This
will make retensioning the shrouds easier. Now, completely remove the plate from the
hull. Dig out all the old caulk to expose the cut edges of the deck. Those of
you who have water entering the salon will almost certainly have water soaked
balsa core in the deck.
In later models of the 320, Catalina
saw fit to make the deck solid fiberglass where the chain plates pass through.
This was not the case with #26. The balsa core was so wet it crumbled without
the support of the caulk. There is no
choice but to remove the soaked core, fill the void with epoxy filler, and recaulk the entire opening.
One way is to bend a nail to create
a 1/2" hook. Remove the head and put the nail in a power drill. Use this to remove as much of the balsa core
as possible. Let the opening stand long
enough to dry more of the core. Use hair
dryer or other mechanical means.
When dry, mix epoxy
with a slow cure hardner and lots of filler to
make a peanut butter paste. (I recommend
the West System product.) Next tape over the deck opening
from the inside. Now, with whatever tools you can muster, force the
putty into the space between the deck and liner taking great pains to fill in a
circular manner so as to force out as much air as possible. Let fully cure. Then reassamble the chain plate with polysuflide caulk or polysulfide/silicone product.
Another method I've heard about is
to again seal the opening from the inside and complete fill the opening, the
entire opening with an epoxy mix that will flow. When hard, simply drill out a new opening
through the now solid epoxy deck.
Do not delay doing this another season. The
rotting core will only get worse. It's
not really that bad of a job. If you
don't count yoursefe handy, do have a yard do the work. Soft decks can make an otherwise clean boat
very hard to sell.
Jeff's instructions give some fine
details and will solve some of the problems I encountered. I'd add that I used
a chamfering bit to bevel the screw holes in the deck. I'm told this gives a
better "pocket" of caulk between the screw and deck. Chamfering is
recommended with any screws through the deck.
I used a pocket knife to loosen the
caulk then pulled it out with pliers. The excess old caulk on the deck I
removed with a dremel tool and small wire brush. Use
care to only remove the caulk and not burn the gelcoat
on the deck not that appearance matters as this area should be under the plate.
Do not buy squeeze tubes of caulk. I
use LifeCaulk by BoatLife.
The stuff is very stiff in the tube and squeezing it out to fill the void is
difficult. My store has tubes of LifeCaulk for use
with a caulkiing gun. There are both the normal long
tubes and short tubes. A short tube is enough for both center plates. Use a
long tube if you are going to do all six.
Doing it in two stages as Jeff
instructs is the way to go. I did it in one step and believe me, Jeff's way is
easier. That is fill the space around the tang to the deck, let it cure
overnight, then do the plate and screws as Jeff says.
Finally, my experts advise to not
tighten the screws fully in assembling the deck plate. Instead, just slightly
more than hand-tight. Let it cure a day or two this way to establish a layer of
caulk. Then, when the screws are tightened the caulk won't be squeezed out
leaving to thin a bead under the plate.
Now, if some enterprising person
would organize the suggestions in this thread, we'd have a nice technical piece
for the 320 website.