Threaded keel plug?

I have recently acquired a 1973 Ericson 29. The boat is on the hard and the hole in question is on the starboard side of the keel just aft of midships. It is a threaded opening for a plug of some sort. The opening is just over a 1/2" and I can not find any plug to fit. Is this a standard fitting? Several attempts to purchase a plug for this were unsuccessful at local businesses with store employees suggesting to contact the boat manufacture for the plug. Any help would be greatly appreciated.

From the description it sounds like someone in the past had a concern about accumulating water in the bilge while the boat was on the hard. The old-fashioned solution (for the last couple centuries) was to put a threaded plug fitting at the bottom of the bilge or keel cavity.
Launching the boat without carefully checking on this would be unwise...


Chances are it takes a common pipe plug, bronze preferred I would imagine.
The old system is/was called a "garboard plug".

I found several pics on the web, and will attach one.

Happy hunting!

Lb

LB, Thank you for the reply. I was not sure if that was an Ericson original or an aftermarket.

The female fitting does indeed look like that. Unfortunately for me I can not seem to find the proper male size. The standard fittings come in typical sizes like 1/2" , 5/8"and 3/4". I tried several sizes and it seems to be between 5/8" and 3/4", which I'm finding out no one seems to carry.

I'm not sure if it is metric or just and odd SAE but I will keep hunting!

Ok, I may be getting closer.

I found this picture online after doing a Google search for "bronze garboard plug". Interestingly enough, I found that pictured T-fitting on-board my vessel with assorted other screws etc. As the picture shows, the T-fitting is threaded into what appears to be the inboard side/portion of the female fitting. I just don't see where I can gain access to the bilge to get to the thread and then screw in the T-fitting.

But then it leaves the question what fitting would go into the outboard side and why have two fittings at all?

I would pretty much guarantee that you only have an external fitting to worry about. Remember that pipe thread is tapered, so it will run in and then bind. You may be battling that there are two standards on pipe thread. The common one you find in your local hardware is NPT - national pipe thread, but, that's not to say someone didn't use a BSPT fitting - British Standard pipe thread - here's a link to someone who carries it - unfortunatly, you're in a trial and error situation to figure this out if you can't find a local source:

http://www.mcmaster.com/#brass-pipe-fittings-and-pipe/=8bvbgm

Of note, the oil pressure switch on my Yanmar 3GM30F is BSPT, so you never know where it will show up

Garboard Plug

My boat has a hollow, horizontal area filled with lead shot below the bilge and solid lead keel. If your boat is the same, you won't get to the garboard plug; this is for draining any water that accumulates in the lead shot area on my boat. Apparently, the water leaks in from the bilge into the lower hollow area when on the hard. Mine is a hole in the fiberglass and came plugged with just a rubber plug. The kind of plug with a bolt through the center and a nut on the outside to snug it up.

On another note, if you have water dripping all the time from this hole then you may need to find where it's coming from and seal it off. For a plug, I'd check to see if one of the tee's screws in from outside, then I'd go to a hardware to find out what thread it is. Once the thread is known, then search the chandleries (internet too) for the right external plug. Could also cut one of the tee's off and slot it for a big screwdriver.

Garboard Plug

Another option, find a slightly larger bronze plug with National Pipe thread and buy a matching tap and drill of correct size. It is simple enough to drill the hole bigger and tap it for the new plug.