[Public-List] MAST SUPPORT BEAM
Mike Lehman via Public-List
public-list at lists.alberg30.org
Fri Nov 6 07:28:09 PST 2015
Chip
This has not been an issue on the liner boats.
There are 2 things that caused the beams to fail on the older boats:
1. the glue gave up. The epoxies today are much better
2. Whitby drilled two holes directly in the center of the beam from the
underside to countersink the bolts holding the deck step in place. The
countersink holes are more than half way through the beam and are large
diameter. This is where most of the stress is on the beam and these holes
severely weakens the beam at the most critical location.
The 2 aluminum plate reinforcement method was developed many years ago by
Bruce Rankin, owner of #244 LinGin, and professor of naval engineering at
the U.S. Naval Academy. It has proven to be a permanent repair and has
withstood the stresses created on boats that that heavily raced in heavy
weather.
I have personally performed this repair on 10 or so boats and it usually
takes about 10 hours from start to finish. There is information of the
Alberg 30 website on how to do this at
http://alberg30.org/maintenance/disorganized/deckbeam/repair/.
For those who would like to cut your own plates, I do have a paper template
that I can copy and mail. A word of caution, I have found that each boat is
slightly unique. So I would use the paper template to create a 1/8" plywood
template and fit it to your boat before cutting aluminum.
The job is not difficult, and can be performed with the mast up (loosen the
shrouds) and with the beam already deflected. I use a screw-type house jack
(like you would find in a basement) and crank up the deformed beam back to
original curvature. Then I go to the doctor and spend $50 for the visit, so
I can get a prescription for anti-inflammatory medicine to relieve the pain
of the deltoid bursitis that I just created in my shoulders.
So have at it!
~~~_/)_/)~~ Mike Lehman ~~_/)~~~
-----Original Message-----
From: Chip Dance via Public-List
Sent: Friday, November 06, 2015 9:06 AM
To: fongemie at gmail.com ; Alberg 30 Public List -- open to all ; JAMES DAY
Subject: Re: [Public-List] MAST SUPPORT BEAM
Has anyone ever found it necessary to replace/rebuild/reinforce the mast
beam on a liner boat? Or was Whitby successful in that upgrade?
Chip
#456
Sent using a stone tablet and chisel.
-------- Original message --------
From: Jeffrey via Public-List <public-list at lists.alberg30.org>
Date: 11/06/2015 4:54 AM (GMT-07:00)
To: JAMES DAY <junkflyboy at yahoo.com>, Alberg 30 Public List -- open to all
<public-list at lists.alberg30.org>
Subject: Re: [Public-List] MAST SUPPORT BEAM
James,
I replaced mine in 2013, and I just used the existing beam to build a
laminating mold for the new beam. The existing beam came out of the boat
easily and in one piece. It wasn't that difficult in the end, should have
done this sooner.
My new beam is made from white oak, and is built a bit taller and thicker
than the original.
I've got some images up here.
http://sailboatseagrass.com/mast-beam-project/
Jeff
Seagrass. #116
Boothbay Harbor, Maine
http://sailboatseagrass.com/
<http://instagram.com/jfongemie>
On Thu, Nov 5, 2015 at 5:40 PM, JAMES DAY via Public-List <
public-list at lists.alberg30.org> wrote:
> I am sure that this has been discussed, but I cant find a search window.
>
> Please advise if any drawings are available to make a new beam to replace
> the wood one that supports the mast on top of cabin. Would like to replace
> this before leaving this winter. I have access to a shop to make one from
> metal, but would like to have a set of drawings, at least the over all
> measurements, and curve. thanks for any help, feel free to send pm to
> junkflyboy at yahoo dot com
>
>
> thank you in advance
>
>
> James Richard day (retired having a ball)
>
>
>
>
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--
______________
Jeffrey Fongemie
<http://instagram.com/jfongemie>
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