(William R. Watt) writes:

Glenn Ashmore ) writes:

...Elements
is a bit more understandable and provides formulas in English and metric.

and graphs for the mathematically challenged

Hmm, serioulsy, if you really are mathematically challenged you should
maybe stay away from structural engineering or any other engineering
for that matter.

Cheers,
--
================================================== ======================
Martin Schöön

"Problems worthy of attack
prove their worth by hitting back"
Piet Hein
================================================== ======================

Martin S says:

Hmm, serioulsy, if you really are mathematically challenged you should
maybe stay away from structural engineering or any other engineering
for that matter.

Hmmmmm...

Steve pulls up a chair...

It's important to note that the remarks made about structural calculations
are accurate, but also note that boats are subject to unknown forces. Many
structural methods used for boats have varying qualities, depending on who
did the work and how much of a hurry they are in. Structural design for
boats uses structural engineering yes, but large margins are built into the
process by using common design rules. Design rules are such things as
expected 'hull pressure factors' based on hull type, weight and speed. The
hull pressure factor is then used to determine spacing of hull support
members, then hull skin or plating is selected (flexural modulus) according
to typical design rules for allow percentages of flex. Finally, the
structure inside the hull, on the required spacing, is determined ...again,
from the hull pressure. It is here, and in skin type and thickness, that
structural engineering and experience come into play. There are many ways
to frame up or provide internal support to a hull, and it requires
engineering knowledge and experience. There is no reason that any
interested person cannot work their way through the learning material and
then do the design, especially for smaller and lower-powered boats (skiffs).
Larger boats should be designed if you are confident that you have the
appropriate training and experience. Note that most states (US again
....sorry) use the term 'architect' for a yacht designer and as such usually
do not have licensing associated with this type of work. Two states,
Washington and some other I can't remember, classify the design work and
have varying requirements. Pressure from governments tends to support
higher regulation and licensing requirements while pressures from industry
support less (to prevent loss of business, higher prices, smaller businesses
not surviving etc). If I were you, I'd go ahead and buy the books that
apply, read them, then decide how far you want to take it...the training and
education or the design work itself. Armchair sports or playing the game.

Brian

--
My boat project: http://www.advantagecomposites.com/tongass

"VG" wrote in message
...
If you call ABS they will be able to answer that question.

Not everybody live in US. Not so easy to call ABS when you can barely
write,
but no speak english. I can understand a slowly oxford english, but a fast
texan (or australian to change country) is far beyond my abilities.

I think the
bigger questions is do you have an engineering background?

Yes.

ABS requires you to know how to calculate section modulus, know
the mechanical properties of your materials, and generally
have an engineering knowledge of structures.


Not a problem. My real problem is to determine the forces that will be
exerced on the hull. In mathematical conditions, I can do some things. But
real life sometimes differs from mathematics.


"VG" wrote in message
...
With at least some lines dealing with displacement (ie non planning)
powerboats in plywood (classical, not stich and glue) , length 30'.

subsidary question :
Does "Guide for building and classing Motor Pleasure Yachts" from ABS
deals
with above powerboats ? Or other regulations 'Lloyds ???)

Thanks for using your time to answer.

Martin says:

Steve pulls up a chair...

Hmmmmmmm...

are you

1) expecting a lecture on why math is fundamental to engineering

or

2) pulling my leg?


Neither - it looked like the start of a good flame war, so I thought I'd get a
ringside seat. Looks like the gauntlet wasn't picked up, though. Just as
well.

Steve

Ok, how about "unpredictable". Sure, you can make reasonable estimates.
Then some guy with big eyes and small brain decides to set a new air speed
record off the top of a wave, only to slam into a BIG wave right after. If
you could guarantee prudent use, you might be able to better estimate loads.

Brian

"Schöön Martin" wrote in message
...
"Brian D" writes:

It's important to note that the remarks made about structural
calculations
are accurate, but also note that boats are subject to unknown forces.

Unknown forces?
Like ESP or telekinesis or "may the force be with you"?

Sorry, I just couldn't resist :-)

But also, there are no such unknown forces IMHO.

snip
not surviving etc). If I were you, I'd go ahead and buy the books that
apply, read them, then decide how far you want to take it...the training
and
education or the design work itself. Armchair sports or playing the
game.

Right and if you feel intimidated by the math and physics you'd better
stay away from it.

Brian

--
My boat project: http://www.advantagecomposites.com/tongass

Go to http://www.multihulls.org/boats/scarlatti/scmain.htm for something
completely different. Please visit the "Technical" section (link at the
bottom) for a very incomplete discussion. Material on structural
engineering will be added as time permits.

Cheers,

--
================================================== ======================
Martin Schöön

"Problems worthy of attack
prove their worth by hitting back"
Piet Hein
================================================== ======================

Wait ...give it time. If someone is mathematically challenged, then it
might also take them awhile to figure out that they've been flamed

bd


"Stephen Baker" wrote in message
...
Martin says:

Steve pulls up a chair...

Hmmmmmmm...

are you

1) expecting a lecture on why math is fundamental to engineering

or

2) pulling my leg?


Neither - it looked like the start of a good flame war, so I thought I'd
get a
ringside seat. Looks like the gauntlet wasn't picked up, though. Just as
well.

Steve

Brian D wrote:

Ok, how about "unpredictable". Sure, you can make reasonable estimates.
Then some guy with big eyes and small brain decides to set a new air speed
record off the top of a wave, only to slam into a BIG wave right after. If
you could guarantee prudent use, you might be able to better estimate loads.

Brian


That's not a unpredictable load, but an unacceptable OVER-load.

It's _supposed_ to break then.

It it doesn't break then, it's built too heavy.


Richard

Martin says:

Oh, I am sorry for having disapointed you. I'll give it a better try
next time :-)

Not your fault, Martin - you threw the gauntlet, no-one bothered to pick it up.
;-)

Steve "doesn't _really_ enjoy flame wars"

"Brian D" writes:

Ok, how about "unpredictable". Sure, you can make reasonable estimates.
Then some guy with big eyes and small brain decides to set a new air speed
record off the top of a wave, only to slam into a BIG wave right after. If
you could guarantee prudent use, you might be able to better estimate loads.

Brian

Right, not even the safest of cars (Volvo?) survive being driven off
a cliff.

Then you have the racing crowd who do things normally not regarded as
prudent...

http://www.multihulls.org/clublinks.html
that kind of sailing isn't regarded as particularly wild. It's a
5 tonne boat, 60'x60' on the water.

Another one: http://www.bonduelle.fr/htm/voile/fdecran/1024/01.jpg
and http://www.zedda.com/news_details.php?ID=37#
but these two does not represent severe load cases (flat water).

I have seen wilder things but don't seem to be able to locate them
again.

Cheers,

--
================================================== ======================
Martin Schöön

"Problems worthy of attack
prove their worth by hitting back"
Piet Hein
================================================== ======================

Richard Lamb ) writes:
Brian D wrote:

Ok, how about "unpredictable". Sure, you can make reasonable estimates.
Then some guy with big eyes and small brain decides to set a new air speed
record off the top of a wave, only to slam into a BIG wave right after. If
you could guarantee prudent use, you might be able to better estimate loads.

Brian


That's not a unpredictable load, but an unacceptable OVER-load.

It's _supposed_ to break then.

It it doesn't break then, it's built too heavy.

a boundry value problem?

the theory of convex hulls is an optimization method in the mathematics of
descision making. thus proving mathematicians are wannabe boat builders
like everybody else.

--
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