[Alberg30] A30 mast support beam

Fri Feb 22 06:28:53 PST 2002

OK, I am caught up now and can spend some time talking about the beam repair 
to the A30.

First let me reinforce what George has already stated: this repair was 
designed by Bruce Rankin who was a professor of engineering at the US Naval 
Academy. Bruce, more than anyone I have ever met, could tell you the sheer 
strength of just about any material just by looking at it. Bob Marshall, 
original owner of #215, also deserves a lot of credit, since he started this 
with some early reinforcement plates over 25 years ago. To the best of my 
knowledge, over 100 Albergs have had this repair and it has withstood the 
test of time on boats that are raced hard (i.e. 28 knots on the deck, gusts 
to 35, full main and #1 genoa).

Having said that, I am not saying there isn't a better way...but I know this 
one works and is permanent. The job is about a 10 hour project.

The mast does not have to be removed. The shrouds need to be loosened 
considerably. As you use a house jack to crank the beam back into place, you 
will need to check the shrouds because it is surprising how much they 
tighten as the beam is raised. It is not uncommon to find a beam that is 
2"-2-1/2" deflected on boats that have been raced hard. Care should be taken 
to make sure you spread the load both top and bottom with several layers of 
2x6's, otherwise you will crush the cabin sole (with or without the mast in 
place). It is advisable, although not necessary, to crank the beam back in 
stages...a couple of turns today, a couple of turns next weekend, etc. 
(depends on how strong you are).

Once you are satisfied that the beam is positioned to the original spot 
(check it with the curve/spacing of the door), you can make a template from 
cardboard. This was not difficult. The after plate is 54"[?] (doing this 
from memory)and the forward plate was 51"[?]. The important part, of course, 
is the top curve and the angle on the ends. Trim the cardboard until you are 
pleased with the fit, then tape into place and simply trace the bottom 
curve. I made the templates about 1/8" narrower than the beam itself. The 
aluminum plates themselves will need 'touch up' with a belt sander, because 
nothing ever fits exactly the way it is supposed to, plus you will want to 
'knock off' the sharp edges. From the reports I have gotten the plates 
provided from my template by Washington Aluminum seems to fit pretty well.

Now that you have a template, it's time to find the aluminum for the job. I 
used 0.50" 6061 grade aluminum and found that it was nearly as expensive to 
buy the raw aluminum and cut it myself as it was to have it professionally 
cut using a water jet process by Washington Aluminum. I spend a whole 
afternoon on the phone looking for local sources and advice from machine 
shops and finally decided on Washington Aluminum, becuase they were local 
and had the experience and the price was reasonable.

Using the belt sander, you can trim the plates until you are satisfied with 
the fit and you are now ready for permanent installation.

All of the existing bolts can be removed from the beam (actually, you can do 
this early because it being supported by the jack). I decided that I did not 
want any additional holes in the beam, so planned to use the exisiting 
holes. Using several "C" clamps, clamp the first plate into place, and using 
a 1/4" x 6-1/2" drill bit, drill from the opposite side just enough to mark 
the plate. Remove the plate once all of the holes are marked, and drill the 
aluminum with 5/16" holes (I increased the bolt diameter because the 
original bolts were all bent). Drill the holes in the wood beam out to 
5/16". Put the plate back in place using the bolts to hold it in position. 
Now clamp the opposite plate in place, and drill enough to mark it just like 
you did the first one. Once everything is drilled put it all together *dry* 
to make sure everything is going to fit.

I used West System aluminum etch to wash the plates so I would have a good 
bond with the epoxy. Mix up thickened epoxy, paint the wood beam liberally, 
getting it into the cracks as much as possible, work rapidly to bolt 
everything together. Clean up your mess and go have a beer.

In a week or so you can remove the jack. Using a marine caulking, caulk all 
the edges, and when dry you are ready for paint. Walla - a permanent repair 
- now pay attention to where the forward lowers attach, because the loads 
are still there you have just transferred them to another part of the boat.

Hope this helps, good luck.

----Original Message Follows----
From: "Furey, Bill (CORP)" <bill.furey at corporate.ge.com>
Reply-To: public-list at alberg30.org
To: "'public-list at alberg30.org'" <public-list at alberg30.org>
Subject: RE: [Alberg30] A30 mast support beam
Date: Thu, 21 Feb 2002 12:34:34 -0500

George: couple of dumb(or maybe not) questions- 1. Can you jack the beam
up(carefully)
with the mast in place-if so-some tips,pls.
2. Assuming one uses the Washington Inc aluminum plates(they have them for
my boat,
A-35($285 a pair)- when you jack up the beam & fasten on the plates, to the
beam-
why won't the beam sag again(this from a non-engineer with a slight dislexic
problem-
maybe they're one & the same)I understand you glass or seal the extremities
& the overhead,
but is this enough??-thks.

-----Original Message-----
From: George Dinwiddie [mailto:gdinwiddie at min.net]
Sent: Thursday, February 21, 2002 11:52 AM
To: public-list at alberg30.org
Subject: Re: [Alberg30] A30 mast support beam

Dan,

Jan Grodzinski posted (on the member list) a company that digitized
and cut the plates for him.  I've copied the company address to
http://www.alberg30.org/maintenance/disorganized/deckbeam/repair.html

  - George

 > Dan Morley said:
 >
 > I have been speaking with Kirk from Washington Aluminum, regarding
 > aluminum plates to reinforce the mast support beam of my 1968 A30.  The
 > shipping / customs procedures for shipping to Canada are expensive and
 > awkward - not to mention the very unfavourable $ exchange!  My beam does
 > not appear to have sagged at all, but is just starting to delaminate.
 > Thus, I think I could use my exisitng beam as a template, and have the
 > plates manufactured locally (but might this be a bad idea?).   I am
 > wondering, however, if there is a chance someone out there already has
 > templates for the repair plates?
 > Thanks
 > Dan Morley (#322)

--
  ----------------------------------------------------------------------
   George Dinwiddie                             gdinwiddie at alberg30.org
   The gods do not deduct from man's allotted span those hours spent in
   sailing.                                    http://www.Alberg30.org/
  ----------------------------------------------------------------------

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