No sorry you are at the wrong end with your diagram. I would definitely say the hole is a drilled purposely all the way through the centreboard.Do you see the hole in this diagram? (see attachement)
OK cheers, I wait a while and see if the Oracle comes along.That hole is not on the CB of my H26. I'd fill it in unless you think you need it. Here is a pic of @Crazy Dave Condon working on my keel. You can see there is no hole in that location.
My best guess is someone may have thought that there was water in the keel and they drilled that hole to let it dry out.
I tagged Crazy Dave on this reply so... I suspect he will chime in if he has an idea of what that hole is about.
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Wow Dave thanks for a comprehensive reply, I'll try to follow the mood. The centreboard is definitely fiberglass, I know this because I was giving the tip a couple of coats of fresh gel coat where it was just starting to show wear to it's polyester gel coating.Just to be sure, there are a couple of questions.
1. Is the centerboard (not keel) made of plastics or fiberglass.
2. If plastic, that is a replacement centerboard.
3. If fiberglass, is that a replacement from the forum store, Hunter Marine or elsewhere?
4. Any idea who drilled that hole.?
5. Any repairs to the centerboard?
Generally the centerboard was built out of fiberglass by Foss Foam now called New Rudder who still maintains the molds. It has a metal frame I think inside it with a construction foam filler. If any water ever got inside, a hole was drilled near the bottom of the centerboard to allow the water to run out and interior of board to dry and then the hole filled in unless some fool thought you needed a hole.
The Macgregor centerboard were two fiberglass sides married together with holes in it to fill up with water. Thus my question as to manufacturer of centerboard and style.
Finally is this a replacement board made out of plastic. If so it will not hurt the construction of the board with that hole but then why that hole.
Finally, if the boat has the original centerboard and it is completely dry , I suggest plugging that hole or repairing it.
Seems like the right move. Worse case scenario is that you figure it out later and redrill the hole.As long as your saying it shouldn't be there I will fill the hole and forget it. Just another one of life's little mystery's!