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<DIV><SPAN class=163464800-24022002><FONT face=Arial color=#0000ff
size=2>Michael,</FONT></SPAN></DIV>
<DIV><SPAN class=163464800-24022002><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=163464800-24022002><FONT face=Arial color=#0000ff size=2>I also
installed the Aluminium plates on #114 with 5/16 stainless bolts and
epoxied both plates against the sanded beam with recommedations from Mike
Lehman. I sailed the entire summer last year without incident. The real
issue with the Alberg is that the laminated beam was glued with
strip material in a horizontal instead of vertical. If the beam was
laminated vertically we wouldn't be having these discussions. I sprayed the
plates with white epoxy paint when the installation was complete and
every guest on board thought the boat came from the factory with those
plates. </FONT></SPAN></DIV>
<DIV><SPAN class=163464800-24022002><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=163464800-24022002><FONT face=Arial color=#0000ff size=2>I can
comment on stainless and its cost from a machine shop, the port retainers
on #114 are 1/4" stainless which were laser cut. The stainless pieces were
installed on two small ports forward and four large ports in the main cabin.
This combination with lexan windows are possibly stronger than the hull. The
cost of these ports and new chain plates from 316 stainless were $1000.00 one of
the most expensive parts in restoring Carina Vela. It can be done but get
ready to spend some dollars.</FONT></SPAN></DIV>
<DIV><SPAN class=163464800-24022002><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=163464800-24022002><FONT face=Arial color=#0000ff
size=2>Stephen</FONT></SPAN></DIV>
<DIV><SPAN class=163464800-24022002><FONT face=Arial color=#0000ff size=2>Carina
Vela </FONT></SPAN></DIV>
<DIV><SPAN class=163464800-24022002><FONT face=Arial color=#0000ff
size=2>#114 </FONT></SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> John Birch
[mailto:Sunstone@cogeco.ca]<BR><B>Sent:</B> Saturday, February 23, 2002 3:57
PM<BR><B>To:</B> public-list@alberg30.org<BR><B>Subject:</B> Re: [Alberg30]
Mastbeam Repair Revisited<BR><BR></FONT></DIV>
<DIV><FONT face=Arial size=2>Hi Michael,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>As someone who has been aboard the
Rankin/Lehman/et al type repairs, and being a 37 guy, I perhaps can add a
note of objectivity. I found the work done to be first rate and not looking
like an add on - in fact most would think they came from the factory that
way.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Being a free country, do as you see fit, but for
my 2 cents the Aluminium job as done by the Chesapeake gang works great.
Taking a another look as to whether it is best is the whole concept of
progress. But their method works and looks good.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Cheers,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>John</FONT></DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=Crufone@aol.com href="mailto:Crufone@aol.com">Crufone@aol.com</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=public-list@alberg30.org
href="mailto:public-list@alberg30.org">public-list@alberg30.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Saturday, February 23, 2002 3:02
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [Alberg30] Mastbeam Repair
Revisited</DIV>
<DIV><BR></DIV><FONT face=arial,helvetica><FONT lang=0 face=Arial size=2
FAMILY="SANSSERIF">George D, Michael L, Dan S, et al,<BR><BR>My original
concern with using Aluminum for this repair was that owners were using SS
bolts in contact with the Aluminum. I see now that Al 6061 alloy is
being used. This is pretty good stuff, aircraft wing ribs are made
from 6061. While 6061 is reasonably corrosion resistant, I have seem
some very nasty SS / AL dissimilar metal corrosion. In the presence of
water vapor it increases and add the Chloride ion and you have the chemistry
for active, runaway corrosion, i.e., a battery.<BR><BR>I didn't think that
Aluminum fasteners would be tuff enough, so I gravitated toward using SS for
both the stiffeners and the fasteners.<BR><BR>I also felt that the SS
stiffeners would be thinner and less obtrusive. Originally I guessed
that the Al plates would be 1/4" thick, but I have now seen references to
both 3/8" and 1/2" thicknesses.<BR><BR>I did some measurements on my boat
#133 from the center of the beam and from both the port and starboard door
jamb down to the sole. I took measurements before and after tuning the
rig and then again before and after the 80 mile maiden voyage down to Lake
Erie. In all cases the mast beam was lowering about twice as much in
the center of the beam as at each of the door jambs, only 12"
distant.<BR><BR>My hypothesis was that the boat wasn't getting noticeably
wider as the mastbeam collapsed and that the center of the beam was
flattening more than the entire beam was falling.<BR><BR>I then thought that
I didn't like the conventional fix by drilling 5/16" holes for bolts through
the wood laminations, in some cases severing the laminations in
half.<BR><BR>It came to me that if one could prevent the laminations from
slipping relative to one another that would solve the majority of the
problem. The idea then came to install bolts or dowels of some
material vertically through the stack of laminations to prevent horizontal
slip. The difficulty would be to install the fasteners without
penetrating the cabin roof.<BR><BR>About this time an Engineer friend of
mine pointed out that if the beam was prevented from flattening then it
could not collapse. He suggested that if a stiff enough piece of
material were laminated to the bottom side of the lamination stack then the
beam would not be able to flatten in the center. This guy mentioned that the
"sistered" Al plates would not even be needed! This played into my idea of
vertical fasteners but against the known fact that the strength of an I Beam
is mainly in the web and not the flanges. <BR><BR>So... I wanted to do both
and came up with the idea of a SS weldment. SS would allow the
material to be thinner and the weldment would have far more strength due to
it's channel cross-section. Hummm......now to address the fastener
issue.<BR><BR>I have not taken the mast base off from the outside of the
cabin roof so I don't know if there is an opportunity to use vertical
fasteners through the mastbeam at that location. Someone mentioned in
one article that the counterbores for the mast base attachment went down
about half way into the mastbeam. This seams excessive, but could
present a location for through fastening the original wooden laminates and
repair channel together. <BR><BR>My thought would be to investigate adhesive
bonding the channel to the original wooden mastbeam. Perhaps not as
the sole method of attachment but as a way to limit the number of mechanical
fasteners. I would consider the location of the mechanical fasteners
carefully, avoiding severing the wooden laminates and staying clear of the
center of the beam and the web area of the beam.<BR><BR>My thoughts on
installation would be to use a router to reduce the thickness of the lower
wooden laminate to receive the channel without any loss of headroom. I
am also considering the use of recessed fasteners so that a thin lamination
of teak could be applied over the SS channel to conceal the metal and give
the appearance of the original wooden beam.<BR><BR>Hope that this clears up
my thought process on the mastbeam repair. I just thought that I would
attempt to combine an effective repair with the original beauty of the
boat. To make the boat sound again without altering her original
looks.<BR><BR>Michael #133</FONT>
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