[Public-List] mast support in liner boats

[via Public-List]

Jason
I suspect I will know sometime this week what the size of the
aluminium beam is and will share the info when I get it.
David

	-----------------------------------------From: "Jason S via
Public-List" 

To: "Ryan Martin via Public-List", "George Dinwiddie"
Cc: 
Sent: Sat, 13 Feb 2016 12:12:05 -0500
Subject: Re: [Public-List] mast support in liner boats

 George,

 There is an aluminum beam in there. How big I don't know just yet but
I
 will let everyone know. I have drill in there a few places and found
 aluminium

 Jason
 #457
 On Feb 13, 2016 11:35 AM, "George Dinwiddie via Public-List" <
 public-list at lists.alberg30.org> wrote:

 > David,
 >
 > On 2/12/16 10:31 PM, via Public-List wrote:
 >
 >> First, I will admit that I have not reviewed the discussion about
mast
 >> supports as I thought this was a problem for older boats as I have
a
 >> liner boat. i will be reviewing this discussion tomorrow morning.
 >> so here is my first question. How is the mast supported in liner
 >> boats. My boat is 432?
 >>
 >
 > The older boats have a laminated wooden beam under the mast. This
beam is
 > supported by the bulkheads, which rest on the hull. The typical
failure is
 > that the glue lines break down and the beam sags.
 >
 > The newer boats have an aluminum beam (I'm told; I've never
checked.)
 > inside the overhead liner. This beam is also supported by the
bulkheads
 > which are supported by the cabin sole liner. The typical failure is
that
 > the liner starts to sag and lets the bulkheads and beam sag.
 >
 > A little info may help. (1) I have seen the repair of the mast step
 >> done on 499. I sure there is water intrusion under the mast step.
(2)
 >> On my boat there are about five bolts that run through the "beam"
that
 >> runs across the v berth bulk head. The heads of the bolt are on
the
 >> aft side of the boat and the nuts are on the forward side of the
boat.
 >> (3) there is a "dimple" in the aft side of the "mast beam". It is
 >> located right under the mast step.
 >>
 >
 > This is a different problem than a beam issue. The older boats have
a
 > masonite core, and it doesn't seem to suffer from rot and
structural
 > issues. The newer boats have balsa core which was not sealed where
holes
 > were made through the deck. When it gets wet and rots, the deck
loses it's
 > strength and sags.
 >
 > Any help would be appreciated. I have a water intrusion on the port
 >> side of the mast step, but do not know its extent but I am am
certain
 >> that now is the time to fix it. The intrusion shows up in the
ceiling
 >> of the head. There is some water dripping down the port side salon
 >> bulkhead. and a small drip in the port side of the v berth just a
few
 >> inches inside the forward side of the v berth bulkhead.
 >>
 >
 > Where the water comes out can be a long way from where it got in.
 >
 > I hope this makes sense. This is way beyond my skills and so I need
 >> any help I can get to give guidance to the pros who will do this
job.
 >> Thanks for any help any of you can provide. I think the thing I
need
 >> first is a good idea of how the liner boats are different from the
 >> stick built boats with respect to the way the mast is supported.
 >>
 >
 > I believe Joe Tokarz may have used marine plywood in the article
you read.
 > Given what I know now, I'd be inclined to use Coosa Board under the
mast
 > step. It's a synthetic substitute for plywood that is lighter and
 > impervious to rot. I haven't re-cored under the mast, but where I
have
 > re-cored, I've used a synthetic foam deck core (Klegecell, in my
case) that
 > is a substitute for balsa. It has no strength on it's own, but when
bonded
 > to the glass on top and bottom is rigid and strong. This approach
would
 > also work under the mast. For that matter, new balsa would work.
The
 > original lasted a long time, and survives mostly in relation to
being kept
 > dry. Given the labor of the job, I'm inclined to use a material
more
 > forgiving of neglect than balsa.
 >
 > If the head doors work fine, then probably you don't have a beam
issue.
 > That would mean it's just a deck core issue. Still a bunch of work,
but not
 > rocket science.
 >
 > David, 432
 >>
 >
 > - George, 543
 >
 > --
 >
----------------------------------------------------------------------
 > When I remember bygone days George Dinwiddie
 > I think how evening follows morn; gdinwiddie at alberg30.org
 > So many I loved were not yet dead, http://www.Alberg30.org
 > So many I love were not yet born. also see:
 > 'The Middle' by Ogden Nash http://idiacomputing.com
 >
----------------------------------------------------------------------
 >
 >
 >
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