Author Topic: Keelson rabbet  (Read 15576 times)

Erick Singleman

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Keelson rabbet
« on: July 13, 2009, 09:57:11 PM »
I think I read somewhere that the later models of the 12 1/2 built by HMC had a rabbet on the keelson for the garboard plank due to some leakage issues with the unrabbetted keel???

I have hull nimer 1498 which is one of the last ten or so HMC 12 1/2 boats built (1941) and she does not have a rabbet in the keelson.

Can anyone verify if rabbets were ever used by HMC, and if so when they started.  I am pretty sure this is the original keelson on my boat.  It spent most of her life in New Jersey, and the owner put bandaid after bandaid on this boat to keep her in the water.  I don't think the wood keel would have been replaced.
The wife says I can have a mistress as long as her ribs are made from white oak.

Steve

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Re: Keelson rabbet
« Reply #1 on: July 13, 2009, 10:25:32 PM »
My understanding is that the original specs for the 12 was a keel plank without a back rabbet.  This made construction a bit easier but resulted in a tendency to leak.  See the series on Sailboat Restoration in Wooden Boat written by Ed McClave a couple of years ago where this is discussed.  I also understand that at some point HMCo switched to using a back rabbet.  This is one of the issues we have been trying to add clarity to, but I am not aware of a definitive word on the topic.

Erick Singleman

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Re: Keelson rabbet
« Reply #2 on: July 13, 2009, 10:29:12 PM »
Thanks Steve,

Also mine boat has a full length one piece bench seat.  I noticed some others seem to have two piece seats.  Was this change know to be done at some point as a go forward change?

Erick
The wife says I can have a mistress as long as her ribs are made from white oak.

Steve

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Re: Keelson rabbet
« Reply #3 on: July 14, 2009, 12:30:12 PM »
A little more in the back rabbet:  The HMC plans from 1938 do show a back rabbet.  The Mystic plans for Nettle (1914) do not show a back rabbet.  I know the Fisher's Island models (hull 1502, for example), do have the back rabbet.  I would live to determine the definitive word on this subject.

As regards the seat construction, the two-piece removable seats were used on earlier boats, but I am not exactly sure when they switch to the one-piece bench.  Your boat almost for sure was built with the one-piece bench.

-Steve

Adam

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Re: Keelson rabbet
« Reply #4 on: July 14, 2009, 06:51:21 PM »
Cut and paste from the Mysteries section of the main site:

When did the 12 1/2 Get A Back Rabbet?
The early boats are prone to leaking at the garboards. This is partially because they were built without a back rabbet. At some point, HMC switched to building with a back rabbet. The challenge is to determine when this switch took place. We know that it was before hull 1450 or so, and after 1170.

Erick Singleman

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Re: Keelson rabbet
« Reply #5 on: July 15, 2009, 01:44:00 PM »
Steve,

Is there any way I can get a copy of the 1938 plans or at least get a peak at them?
The wife says I can have a mistress as long as her ribs are made from white oak.

Steve

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Re: Keelson rabbet
« Reply #6 on: July 15, 2009, 02:01:48 PM »
I'm pretty sure that the 1938 plans are in the custody of the Hart Nautical Collection at MIT.  The curator there is Kurt Hasselbalch.  Try Kurt@MIT.edu.

Erick Singleman

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Re: Keelson rabbet
« Reply #7 on: May 17, 2013, 02:24:46 PM »
I was looking at this old thread and decided to post because I have corrected information to add.  Initially I thought my old keelson had no rabbet however when I got to that phase of the reconstruction I noticed upon closer inspection that it did have remnants of a rabbet most of which had deteriorated, broken off, or were hidden by caulk.
The wife says I can have a mistress as long as her ribs are made from white oak.

Steve

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Re: Keelson rabbet
« Reply #8 on: May 18, 2013, 12:16:53 PM »
Thanks Erick.  That is consistent with our previous observations.