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Harryproa skin thickness?   Message List  
Reply | Forward Message #5025 of 6656 |
Re: Harryproa skin thickness?.

-This seems too much glass. Maybe that on the bottom, but the rest
about half that except maybe between the beams on the lw hull. The
rest of the boat has very little in the way of sailing loads.
I was looking at 600g glass for the skins of a 50'/32'Harry but was
considering an extra layer on the bottom for abrasion resistance. I
was also looking at either 10 or 12mm core, eeven considering double
layers of 6mm for tight bends, but Rob reckons I can probably get away
with not needing to do this-- In harryproa@..., Gardner
Pomper <gardner@...> wrote:
>
> Hi,
> I finally got hold of a copy of Dave Gerr's "Elements of Boat Strength",
> which looks to have lots of good information, but it states that is
really
> is not for multihull design, so I am not sure what to use and what to
> ignore. From the various equations he lists, adjusted as best I can
for a
> proa design, it seems that a 50' proa hull for something like Visionarry
> should be built with 3 layers of 600gsm fiberglass cloth on the
outside and
> 2 layers on the inside, with a 14mm core. Is that similar to the actual
> construction? If not, please correct me. If you could explain the
> differences, because of the proa design or my limited undertanding,
I would
> be grateful.
>
> Thanks,
>
> - Gardner
> York, PA
>





Wed Feb 4, 2009 4:35 am

cateran1949
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Message #5025 of 6656 |
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Hi, I finally got hold of a copy of Dave Gerr's "Elements of Boat Strength", which looks to have lots of good information, but it states that is really is not...
Gardner Pomper
gardnerpomper
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Feb 3, 2009
5:23 pm

-This seems too much glass. Maybe that on the bottom, but the rest about half that except maybe between the beams on the lw hull. The rest of the boat has very...
Robert
cateran1949
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Feb 4, 2009
4:35 am

Robert, I am just taking from Dave Gerrs book, which is for power and sail, so he isn't particularly concerned with sailing loads. I calculated based on a 50' ...
Gardner Pomper
gardnerpomper
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Feb 4, 2009
1:16 pm

G'day, I have not read Gerr's book, but he is highly recommended. According to our engineer he is way off. One layer of 600 inside and out, doubled up on the...
Rob Denney
proaharry
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Feb 4, 2009
1:48 pm

I was wondering about the side loads and compression loads on the long lee bow and whether some extra is needed for these. ... unstayed masts. ... Strength", ...
Robert
cateran1949
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Feb 5, 2009
9:51 am

G'day, It is not that long (25% of the boat length), and apparently does not need any more than it has. On Solitarry, there is a couple of 100mm wide 450 gsm...
Rob Denney
proaharry
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Feb 5, 2009
10:47 am

-Fair enough. Probably wouldn't hurt to have a small rubbing strake for cosmetic protection. I can't see that the ww hull would need any more than 450g +/-45...
Robert
cateran1949
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Feb 5, 2009
12:27 pm

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