CD 27 BILGE CRACK

[davidkinzie]

Hello all,

On a 1981 CD 27 (new to me) after TSP'ing the bilge in preparation for epoxy paint, a crack running the length of the bilge was discovered. It appears to be as much as 1/4" wide in places with another arm shooting off about 1/8" wide. The bottom is blistered and has been prepped for a barrier coat. There are a couple of small impact repairs low on the keel that continue to weep moisture though they are not in proximity to the bilge. Photos of bilge and one repair low on keel attached.

Anyone experience cracking of this nature in the bilge?

Does this look like de-lamination issue due to the bilge being constantly saturated or does it look like a structural (ie keel impact...etc) issue? Any thoughts or advice would be greatly appreciated!

I plan to grind the cracks to see if / how far the crack extends into the laminate. Then if the problem doesn't appear too serious (ie. structural) fill, glass and epoxy paint

Should I be more concerned about a structural issue at this point?

Dave.

[tjr818]

We have a 1981 27 too and I cannot picture where you are in the bilge. We don't have anyplace that looks like that on Sláinte. Can you give me a better idea of where this area is? Have you tried to probe the crack to measure the depth? Where is (or was) the boat located? Could that be freeze damage?

[Steve Laume]

That certainly looks like damage from freezing. If it wasn't in the bottom of the bilge it would be a pretty straight forward repair. Getting down in there will be the hard part.

I would drill holes at the end of the cracks to relieve stress then grind away both sides of the crack to get as much taper as you can and clean up the contact area for the repair. Drying out the ballast area as much as possible before you seal it would be a good thing but I don't have any advice on the best way to go about that. Once it is clean dry and prepped, make up a patch of glass layers with epoxy. The first layers you set down should be the widest and turning up onto the inside of the hull would help to bind things. The successive layers of glass should get progressively narrower until you build up a laminate at least as thick as the surrounding area.

Then you can go back and do the painting you set out to do in the first place, Steve.

[davidkinzie]

After grinding with a dremel the cracks can be seen extending significantly into the laminate.

Question is....

"V" the cracks now...

or

continue to grind looking for solid laminate?

I plan to fill with (Watertite, Marine Tex..etc....) and laminate with epoxy resin...

Grinding will lead to more filling and not necessarily improve overall strength of the area as epoxy laminating will....Correct?

[Steve Laume]

Dave, I copied your thread over to the main board where you will get better exposure. Hope it helps, Steve.

[tmsc]

Dave,

Big question here. Where is the boat kept? If not in a freeze zone has it always lived in a non freeze zone? Do you know for sure the crack has not been there for some time? Was the laminate soft in the areas of the cracks? Is the area just cracked or is there deformation? In other words is the area level? Are you finding glass reinforcement in the resin as you grind? Its hard to tell from the pictures, and I have seen in omitted by builders before. Looks like you have the bottom down to bare gel coat if so have you found any significant damage, crazing, or signs of previous repairs to the keel? Its hard to tell but it looks like this near or just aft of amidships, is this correct? Sorry for all this questions need a little more info. In any event, water needs to come out and area repaired and Steve has given you some good advice in that respect.

[OtterHill]

A lot of the guys on here have a lot more experience with this stuff than I do... but I had a similar problem with my 25 last year. I ended up grinding out the crack as best I could, then putting a space heater in the bilge and a fan above that in order to dry it out. I also used a shop vac tapered to a narrow hose to suck whatever moisture and grit out that I could. And acetone. It took over a month, maybe even two, to dry completely. Then I glassed it. The crack extended far enough back that I used a big kitchen spoon taped to a stick to ladle thickened epoxy into the crack, then a yardstick to unroll the cloth. It was a pain, but came out quite nice.

On the outside of the keel, I had to grind out a bad patch from the water damage and refill/reglass that. The biggest chore was getting it all dry--that and reaching into the bilge to do the work.

Hope that helps.

Jon

[davidkinzie]

Hello All,

Thanks for all the input!

Yes the boat lived in Illinois for most of its life so likely freeze damage. Hope so. There are couple of weeping keel repairs that I don't believe are related by impact damage etc. Wet laminate is likely sending bilge crack moisture through the path of least resistance.

Grinding in the small and deep bilge is becoming a pain. Sanding is not aggressive enough.

I'm thinking paint stripper but concerned about it's effect on the polyester resin in the laminate, especially if it makes it's way deep into the crack during application or removal. I could grind the crack out again after stripping but might not get it all. Caution is advised that 8 hrs or so is the maximum you want non (methylene chloride or caustic agents) strippers on glass or gel coat.....

Any advice ? Keep grinding ?

Also, filling the crack, should I consider un thickened (no HD filler) for the first injection to achieve better penetration deep into the crack (but less strength), following up with filler?

Only want to do this once
Dave.

[davidkinzie]

....ps could this rust colored weeping be tainted from the cracked bilge leaking into the lead ballast ( apparently lead does not rust though ) or is it a polyester resin reaction to moisture in the laminate?

[davidkinzie]

...sorry, picture.