[Public-List] mast support in liner boats

[via Public-List]

George
thanks a ton. My doors do fit fine so it is great to know that I may
not have a beam problem. From what i have seen of Joe's work,repairing
seepage under the mast plate does not seem too daunting.
David

	-----------------------------------------From: "George Dinwiddie via
Public-List" 

To: "Alberg 30 Public List -- open to all"
Cc: 
Sent: Sat, 13 Feb 2016 11:35:23 -0500
Subject: Re: [Public-List] mast support in liner boats

 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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