Weeping keel

[Benjammin]

I’ve been watching a bulge on the starboard keel since purchase in 2016. Rust stains and signs of surface delamination led me to have it explored before repainting the bottom. After grinding off the patch it peed water for 10 minutes. Further investigation revealed a saturated foam compartment above the transverse crack. Still investigating but am curious if anyone knows how many keel voids the 34/35s have and any insight into how this started taking on water.

 

[dmax]

I have a 35 with a lead fin keel, can't tell if yours is lead or cast iron. Mine has 3 pockets filled with foam as shown here:

at the top as

 

[JamesG161]

It is Lead, see his pictures of hammer marks.

Jim...

 

[dmax]

Thought it was lead but most of the 34's were cast iron so didn't want to assume. The stains might not be rust, could be from the foam.

 

[Benjammin]

I have a 35 with a lead fin keel, can't tell if yours is lead or cast iron. Mine has 3 pockets filled with foam as shown here:View attachment 216047at the top as

That’s very helpful, thanks! The horizontal crack is at the floor of the chamber so I suspect water got in and froze (it’s a Great Lakes boat) causing the lead to split.
From your photo, I’m guessing the water got into the foam from a keel hull joint sealant failure. I’ll pass that along to my repair guy.

 

[shemandr]

Why in the world would a builder put those foam pockets in a keel? To save money on lead or iron? I'm having trouble understanding what the possible reason would be. Is/was this a common practice? I don't recall ever seeing that before.

 

[dmax]

No idea, I had the foam removed. Never saw it before either. Maybe they wanted to reduce the ballast weight a bit without changing the shape/size, fine tuning.
Benjamin: sounds right.

 

[JamesG161]

I'm having trouble understanding what the possible reason would be [foam core inside]

Hydro Dynamics

Designer needed shape, but had too much weight with Lead.
Jim...

 

[heritage]

The designer may have intended the keel to be made iron.

 

[eherlihy]

The original design of the 34 used a cast iron (7.874g/cc) keel. When O'day switched to lead (11.34g/cc) they needed to reduce the amount of metal used in order to achieve the same ballast ratio.

One great aspect of the upgrade from iron to lead for the keel is that because there is more weight in the lower part of the keel, the center of gravity is lower, thereby making the lead keel boats more stable.

This is the best picture that I have of the foam in the keel, taken when I had my keel bolts replaced.