why don't you just BUILD one of your designs,and stop all the
BULL****???

Hi

Sorry , I didn't ansver this question ;

"2) Are displacement/stability parameters easily calculable by a
formula
or design chart for each scale ratio?"

Easy --- as curves describing the exact displacement for stability.
Waterlines and secions follow useal drawing rules but 3D-H expand
this perception now you can make double hollow structures things you
can't emagine but master on a screen, ---- and it will be there when
the framework is assembled.
For thousands of years naval architecture been in the minds of often
totaly unskilled craftmen producing the most beautifull wonders, in the
17' century in this contry, only the king could build knowleage such as
top technology naval design was for the few, an academic issue about
keeping the secrets to oneself , I build and designed boats none of
these failed but beside I am a boatbuilder lectured boatsbuilding
acturly, proved my idears and abilities as profesional you can be,
being surrounded by famous and known designers and architects --- do I
maneage to design a rugid life saving boat do the sun rise every day.
What calculations do you want --- acturly it's about doing it simpler
avoiding the calculations or make them do somthing , alway's wondered
what people want these calculations for, it's all there when you build
it.

On 15 Jan 2005 08:49:10 -0800, "Narasimham"
wrote:

Am mechanical engineer with a composites background presently residing
in south India. After recent Tsunami disaster, toying with the idea to
help make hand /sail/outboard moter powered fiberglass fishing boats of
standard 30 feet length. Raw materials .. chopped strand mat,
fiberglass cloth, polyester resin and rigid PU foam are commercially
available locally, as is semi-skilled labour who could make boats to
pre designed drawings.

Can someone help to guide in the following ?
Shapes: Are drawings available on net? or on payment? What hull shape
is better? U? Flatbottom?

Do Lloyds or other certifying agencies based in Europe/US have a
branch or mechanism to test and certify marine craft after fabrication
and testing when involved right from beginning stages in India?

If existing wooden hull shapes are duplicated but replaced by solid
fiberglass laminate or polyurethene foam (closed cell to keep out
water) sandwich, would it serve the purpose with stability resisting
wave forces with adequate margin before capsizing?

If the density of the new hull materials duplicates the wood, the
capsize behavior won't change. If the new hull is thicker or thinner
but weighs the same overall the behavior still won't change enough to
notice.

For a physics picture of stability:

1) Is metacentric height a parameter to assess stability?

Yes, it is one factor.

2) Draft. On what factors is load-depth of immersion relations
established?

The volume of the immersed part of the hull displaces the weight of
the vessel in water. That is what displacement means.

HTH



Rodney Myrvaagnes NYC J36 Gjo/a


Capsizing under chute, and having the chute rise and fill without tangling, all while Mark and Sally are still behind you

Here are some links to local fiberglass ocean going commercial fishing boat
builders. You might try emailing them.
http://www.peiboats.com/
http://www.huttboat.ca/
http://www.fourportsmarine.com/
http://www.magnamarine.com



"Narasimham" wrote in message
oups.com...
Am mechanical engineer with a composites background presently residing
in south India. After recent Tsunami disaster, toying with the idea to
help make hand /sail/outboard moter powered fiberglass fishing boats of
standard 30 feet length. Raw materials .. chopped strand mat,
fiberglass cloth, polyester resin and rigid PU foam are commercially
available locally, as is semi-skilled labour who could make boats to
pre designed drawings.

Can someone help to guide in the following ?
Shapes: Are drawings available on net? or on payment? What hull shape
is better? U? Flatbottom?

Do Lloyds or other certifying agencies based in Europe/US have a
branch or mechanism to test and certify marine craft after fabrication
and testing when involved right from beginning stages in India?

If existing wooden hull shapes are duplicated but replaced by solid
fiberglass laminate or polyurethene foam (closed cell to keep out
water) sandwich, would it serve the purpose with stability resisting
wave forces with adequate margin before capsizing?

For a physics picture of stability:

1) Is metacentric height a parameter to assess stability?
2) Draft. On what factors is load-depth of immersion relations
established?
Hope not a tall order. TIA for all helpful tips.

G.L.Narasimham

If you go to the boatdesign.net forums, there are active threads concerning how
we can help in that area.
Try he
http://www.boatdesign.net/forums/forumdisplay.php?f=26

Steve
Stephen C. Baker - Yacht Designer
http://members.aol.com/SailDesign/pr...cbweb/home.htm

You might try talking with the fishermen in the area since they have long
experience of what shapes work and which ones don't work well for their
waters. Then work from there.

Brian

On Sun, 16 Jan 2005 09:14:52 -0800, "Brian Combs"
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

You might try talking with the fishermen in the area since they have long
experience of what shapes work and which ones don't work well for their
waters. Then work from there.

I agree. I see the boats they use, and they look very seaworthy in
shape and design.

And after all they are the one that are going to use them. It will be
easier to persuade them to use the boats, and their lives are the ones
at stake.

Proposal is for new techniques. Fishermen may not imbibe new ways of
boat construction without training.

Brian Combs wrote:
You might try talking with the fishermen in the area since they have
long
experience of what shapes work and which ones don't work well for
their
waters. Then work from there.

Brian

They are handed down from experienced masters or just duplicate
existing shapes. As marine technology has developed so much, expect
that standard/recommended design methodology or practice has become
available,one can start from an instruction manual.

The Pangas are derived from some free FAO designs;
http://www.fao.org/documents/show_cd...E/W7260E00.htm
Those FAO boats are cheap to build and operate but don't plane. If you
sligthly modify the FAO boats by making the aft part of the bottom
straight, they plane with larger engines. The similitude between them
and "pangas" is striking. Those modified FAO boats are also common in
Asia, Indonesia, Philippines etc. It looks like they all derived from
the same set of plans.
There are also Panga plans for amateurs at our web site:
http://boatplans-online.com
Per could even build them from 3D honeycomb, we sell that stuff under
the name Nidacore ;-)
but they would be too light and it would go against the program of the
boat: eays to build and maintain with locally available materials and
skills.

To the original poster, I would say, get the free FAO plans from the
link above.

Jacques from bateau.com


Narasimham wrote:
Brian Combs wrote:
You might try talking with the fishermen in the area since they
have
long
experience of what shapes work and which ones don't work well for
their
waters. Then work from there.

Brian

They are handed down from experienced masters or just duplicate
existing shapes. As marine technology has developed so much, expect
that standard/recommended design methodology or practice has become
available,one can start from an instruction manual.