If you live in a freezing climate you either want to displace the water or drain it. A garboard plug has its own liabilities. I'd prefer the builders didn't build inaccessible cavities into boats as generally bad practice. Mine has the same hollow keel that many have, I haven't filled it yet but I have dried it out and sealed the ingress.
Hollow Keel
- Thread starter psneeld
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Jeff F
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My concern is that displacing all the water is almost impossible, and small amounts of water if trapped will break down the materials in the freeze/thaw cycles. If you can keep the cavity dry you don't need the foam, and if you allow water to get in you don't want the foam.
I have a closed in keel on my current boat and don't like it. But I'm not losing sleep over the possibility that it might have water in it. Doesn't change the behaviour or safety of the boat underway as far as I can tell, and when hauled can be drained. I think that garboard drains are on balance good things for boats that winter ashore.
The previous owner of my boat pointed out that the compartmentilization provides a layer of protection against grounding. Punching a hole in the keel won't sink the boat. I've wondered whether this was a rationale for building it that way. Could have been. I can't see why it couldn't have been left open, so there must have been a good reason to close it in.
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rslifkin
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Interesting question. My boat has a keel, but not an overly deep one. It's not closed off at all inside, so it's just used as a bilge sump (which is maybe 15 inches at its deepest point).
Cored hull boats get water in the core, freezing does not seem to damage them. There isn't that much real water volume and water expands only a little when it freezes. There are thousands of boats in the north that demonstrate this. But I would prefer as you do to keep it dry or displace the water entirely. My boat (AT34) has the keel cavity closed over, then they drilled a bunch of holes in it to mount stuff, guaranteeing leaks. It had a small access hole (1") covered with a piece of Coosa held on with yet more screws and holes. I've sealed the holes and dried the cavity, made the access hole resealable.
If I someday have extra cash and nothing to do I might foam it with epoxy. The epoxy foam isn't like urethane, it is not flexible, sticks tenaciously, and will not absorb water. Effectively, it makes the space solid, and would have the same benefit (more, actually) for grounding. Puncturing the skin would have no effect.
If I someday have extra cash and nothing to do I might foam it with epoxy. The epoxy foam isn't like urethane, it is not flexible, sticks tenaciously, and will not absorb water. Effectively, it makes the space solid, and would have the same benefit (more, actually) for grounding. Puncturing the skin would have no effect.
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psneeld
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I have one of those boats that suffered freeze damage in a SOLID but saturated fiberglass hull and an entire interior teak veneer failure from humidity saturated veneer that de-laminated from up north freezing and it caused a mess.
Water to ice supposedly increases in size around 9 to 10%. How much does it take to break a glue, polyester, epoxy bond microns thick?
My vote is my action too.... you never know when water may migrate back into the keel, you never know whether you got a perfect foam out...so I have let her ride for 10 years and hard cruising and have had ZERO issues. Drained it once, patching any obvious entry points and went cruising.
Water to ice supposedly increases in size around 9 to 10%. How much does it take to break a glue, polyester, epoxy bond microns thick?
My vote is my action too.... you never know when water may migrate back into the keel, you never know whether you got a perfect foam out...so I have let her ride for 10 years and hard cruising and have had ZERO issues. Drained it once, patching any obvious entry points and went cruising.
Jeff F
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I won't argue against the efficacy, but it seems like a big effort to solve a small to nonexistent problem.
It sounds like our boats are pretty similarly configured. I miss a deep bilge, and if I were considering a modification I think it would be to cut open the top and put a pump at the bottom. But honestly this is nowhere near my top ten list, and I'm not sure my idea would stand up to close scrutiny. As I said earlier, it's common enough for me to believe that it wasn't done by accident.
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psneeld
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I see no advantage of opening up the deep keel on many of the Taiwan boats....deep and maybe impossible to keep dry because of the shaft log area poor design...it might get nasty, hard to clean, accumulate stuff that rolls/falls down in there and tough to get out.
It might introduce more bilge odor than if left separate or only accessed through a small access where a pump hose could be sent to see whats in there and then sealed up again.
It might introduce more bilge odor than if left separate or only accessed through a small access where a pump hose could be sent to see whats in there and then sealed up again.
