[Public-List] mast support in liner boats

[Jason S via Public-List]

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
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>
>
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