repair of concrete ballast

[kevnh]

My SunCat came to me from the previous owner with quite a bit of water and antifreeze in the bilge.
Kind of a mess, I thought, but surmised that basically I would just have to deal with rainwater getting in there through the cabin tops and portlights.
As I looked more closely I came to realize that the concrete ballast had been seriously degraded due to freeze/thaw.
Some reading on the CP16 forum confirmed that this can be common on older boats, though I remain a bit surprised that it could happen to such an extent on an only 12 yrs old boat.

Anyway, last fall I sucked all the water and sand out of there with a ShopVac (multiple batches worth), and chipped away at the remaining concrete until I hit good solid material.  In all, I probably removed about half of the original amount of ballast material.  Let that thing dry out well over the winter.

Last couple weeks, using some guidance from Gerry at Hutchins, I installed plywood dams at the proper location and refilled the ballast with most of a 40lb bag of Sakrete mix. 
Overall, I think it came out well.  Can't wait to get her in the water!  Keep your bilge dry if you live north of the Mason Dixon!

Before picture, with broken down concrete aft of the centerboard trunk where it doesn't belong:


After picture, with plywood dams still in place: (had to trim away a bit of liner to get access)

[skip1930]

Looks as if several 5 gallon [hard to judge the amount] pots of 2 part polyester resign needs to be poured into those voids to cap off the cement turning to concrete [in 88 years] UP TO the bottom of the liner.

Then resign impregnated glass cloth to make all that 'disappear' and paint her up nice.

... Really? Antifreeze dumped into the moisture within the keel ballast ? Not you kevnh, but somebody dumped antifreeze into the cement? It's known antifreeze does not evaporate. I can only imagine the mess. How did you get this sticky gelatinous mixture out of the boat?  

So you believe the water entered the ballast through the topside. So no scarfs under water in the keel?

I had a few chips in the glass of the keel, but never down to the cement, so I sanded and filled with [I forget right now what I used. It's a two part.] , AHHH yes ... it was Marine-Tex ...  smoothed and painted. No water ever entered the keel.

Years ago on the CP-19 I band saw cut a 6mm 'KEEL BOOT' and glued that on to the flat bottom of the keel so the keel can roll over rocks without chipping away the glass. Works great. Even have a few scares in the aluminum.

skip.

[kevnh]

Skip, that's an interesting idea.  It would be quite a lot of resin.  But I like that it would give the liner some support in that area.
Alternatively, do you think I could use some expanding foam like Hutchins uses under the forward part of the liner?

The antifreeze/sand mixture was quite a mess.  Took me a while to figure out "what is that sweet smell in here?"
Outside of the keel looks undamaged so I'm optimistic the water came from above.  I'll find out for sure soon enough!

[capt_nemo]

kevnh,

I wouldn't worry too much about supporting the liner in that area which is used for storage. If  you plan to put heavy items in there then consider supporting it with some thin pressure treated lumber wedged in place. Expanding Foam is another alternative, but messy and NOT EASILY REMOVABLE if desired.


When I first purchased "Frisky" in 2010 I found access to the bilge unsatisfactory. So I cut out some of the liner and made a thin plywood cover for the enlarged opening. It never interfered with storing items in that area.
capt_nemo

[kevnh]

Thanks Capt Nemo,
My fearless slicing of the liner was inspired by your previous post on that topic.
I'll probably do a similar plywood cover as my plan A; I checked again today and the liner right at the cut edge there still feels plenty strong.

Did we figure out why they place the bilge pump inlet way up there on the concrete, where it seems like it should instead sit behind the ballast where the first 10" or so of water will collect.

-kevnh

[skip1930]

Expanding foam? The only way this works is to have two 55 gallon drums of two part foam and an application gun ... the kind that is used to fill corrugated shipping boxes, lay in a plastic sheet, and place an item into the box, displacing the foam and 'locking' in the item for shipping.

I think that's the kind of set up Hutchins has.

The foo foo cans I don't think will be satisfactory. Can't put the foam where it needs to go because the Great stuff won't flow and form.

Messy-messy-messy.

skip.

[capt_nemo]

 kevnh,

My bilge pump intake hose was placed correctly down inside the deeper "Well" formed aft by the wall of concrete ballast.

The problem was I couldn't see it clearly or inspect the entire bilge area with the original cutout. Hence the enlargement effort.

By the way, glad some of my documented experiences with photos are proving helpful to others.

capt_nemo