Hull structural grids
 

The erronious idea that lots of boats were built with a "geodesic grid
inside them that completely obstructs the cabin" has been raised by DSK.

A geodesic structure is usually one which encloses a space -such as a
dome. The term geodesic refers to the great circle in geometry and
typically the circle is used to define a dome which forms a thin shell.
Thin shell hull reinforcing would be of no use in hull design as the key
to stiffness is to increase the inertial moment of the hull surface
without increasing weight. This explains why space frames and trusses
and 'structural grids' (a type of 3D truss) are used quite widely. You
may not realise it, but a foam cored sandwhich is also a 3D truss with
the bubbles forming the space between webs. The racing yacht designs
that incorporate these structures would not allow them to completely
obstruct the cabin as there would be no place to pack sails etc. In any
case, to do that would move hull material to the center of the hull
where it would be of less value in limiting hogg/sag etc. (compared to
increasing material on the far hull side).

It follows that there is an optimum hull thickness for any particulr
construction method. At design extremes where the hull is all truss with
a fabric coating we approach the design of the Zepplin. At another
extreme we see the submarine where closely spaced ring girders reinforce
the pressure hull and help reduce hull compression with depth.

Cheers MC

Hull structural grids
 

So why aren't honeycombed bulkheads used like on airplanes?

CM

"The_navigator©" wrote in message
...
| The erronious idea that lots of boats were built with a "geodesic grid
| inside them that completely obstructs the cabin" has been raised by DSK.
|
| A geodesic structure is usually one which encloses a space -such as a
| dome. The term geodesic refers to the great circle in geometry and
| typically the circle is used to define a dome which forms a thin shell.
| Thin shell hull reinforcing would be of no use in hull design as the key
| to stiffness is to increase the inertial moment of the hull surface
| without increasing weight. This explains why space frames and trusses
| and 'structural grids' (a type of 3D truss) are used quite widely. You
| may not realise it, but a foam cored sandwhich is also a 3D truss with
| the bubbles forming the space between webs. The racing yacht designs
| that incorporate these structures would not allow them to completely
| obstruct the cabin as there would be no place to pack sails etc. In any
| case, to do that would move hull material to the center of the hull
| where it would be of less value in limiting hogg/sag etc. (compared to
| increasing material on the far hull side).
|
| It follows that there is an optimum hull thickness for any particulr
| construction method. At design extremes where the hull is all truss with
| a fabric coating we approach the design of the Zepplin. At another
| extreme we see the submarine where closely spaced ring girders reinforce
| the pressure hull and help reduce hull compression with depth.
|
| Cheers MC
|
|

Hull structural grids
 

They are.

Cheers MC

Capt. Mooron wrote:

So why aren't honeycombed bulkheads used like on airplanes?

CM

"The_navigator©" wrote in message
...
| The erronious idea that lots of boats were built with a "geodesic grid
| inside them that completely obstructs the cabin" has been raised by DSK.
|
| A geodesic structure is usually one which encloses a space -such as a
| dome. The term geodesic refers to the great circle in geometry and
| typically the circle is used to define a dome which forms a thin shell.
| Thin shell hull reinforcing would be of no use in hull design as the key
| to stiffness is to increase the inertial moment of the hull surface
| without increasing weight. This explains why space frames and trusses
| and 'structural grids' (a type of 3D truss) are used quite widely. You
| may not realise it, but a foam cored sandwhich is also a 3D truss with
| the bubbles forming the space between webs. The racing yacht designs
| that incorporate these structures would not allow them to completely
| obstruct the cabin as there would be no place to pack sails etc. In any
| case, to do that would move hull material to the center of the hull
| where it would be of less value in limiting hogg/sag etc. (compared to
| increasing material on the far hull side).
|
| It follows that there is an optimum hull thickness for any particulr
| construction method. At design extremes where the hull is all truss with
| a fabric coating we approach the design of the Zepplin. At another
| extreme we see the submarine where closely spaced ring girders reinforce
| the pressure hull and help reduce hull compression with depth.
|
| Cheers MC
|
|

Hull structural grids
 

The navigator© wrote:

The erronious idea that lots of boats were built with a "geodesic grid
inside them that completely obstructs the cabin" has been raised by DSK.

A geodesic structure is usually one which encloses a space

Wrong. The term 'geodesic' refers to the structural elements, which for a
'geodesic' structure are always equilateral triangles. Ever heard of
Buckminster Fuller?



.... At design extremes where the hull is all truss with
a fabric coating we approach the design of the Zepplin.

Or a kayak, if you like to stick with boats (since that's what we're talking
about).

At another
extreme we see the submarine where closely spaced ring girders reinforce
the pressure hull and help reduce hull compression with depth.

Not a good example, the opposite extreme would be monocoque hull with no
internal structural members at all. Does such a thing exist?

Good cut-n-paste work Navvie©, now all you have to do is work on your
reading comprehension.

Fresh Breezes- Doug King

Hull structural grids
 

Try looking geodesic up in a dictionry before you post eh? Thanks for
the compliment, I wrote that all myself. It is my copyright.

Cheers MC

DSK wrote:

The navigator© wrote:


The erronious idea that lots of boats were built with a "geodesic grid
inside them that completely obstructs the cabin" has been raised by DSK.

A geodesic structure is usually one which encloses a space


Wrong. The term 'geodesic' refers to the structural elements, which for a
'geodesic' structure are always equilateral triangles. Ever heard of
Buckminster Fuller?




.... At design extremes where the hull is all truss with
a fabric coating we approach the design of the Zepplin.


Or a kayak, if you like to stick with boats (since that's what we're talking
about).


At another
extreme we see the submarine where closely spaced ring girders reinforce
the pressure hull and help reduce hull compression with depth.


Not a good example, the opposite extreme would be monocoque hull with no
internal structural members at all. Does such a thing exist?

Good cut-n-paste work Navvie©, now all you have to do is work on your
reading comprehension.

Fresh Breezes- Doug King

Hull structural grids
 

Now you are saying a Buckminster fullerene has bonds arranged as
equilateral triangles? Bwhahhahahahaha. You know nothing about chemistry
too!


Cheers MC

DSK wrote:

The navigator© wrote:


The erronious idea that lots of boats were built with a "geodesic grid
inside them that completely obstructs the cabin" has been raised by DSK.

A geodesic structure is usually one which encloses a space


Wrong. The term 'geodesic' refers to the structural elements, which for a
'geodesic' structure are always equilateral triangles. Ever heard of
Buckminster Fuller?




.... At design extremes where the hull is all truss with
a fabric coating we approach the design of the Zepplin.


Or a kayak, if you like to stick with boats (since that's what we're talking
about).


At another
extreme we see the submarine where closely spaced ring girders reinforce
the pressure hull and help reduce hull compression with depth.


Not a good example, the opposite extreme would be monocoque hull with no
internal structural members at all. Does such a thing exist?

Good cut-n-paste work Navvie©, now all you have to do is work on your
reading comprehension.

Fresh Breezes- Doug King

Hull structural grids
 

You have to doubt that he knows what "geo" (as in geodesic) implies?

Cheers MC

Capetanios Oz wrote:

On Wed, 12 Nov 2003 18:26:31 -0500, DSK
wrote:


The navigator© wrote:


The erronious idea that lots of boats were built with a "geodesic grid
inside them that completely obstructs the cabin" has been raised by DSK.

A geodesic structure is usually one which encloses a space

Wrong. The term 'geodesic' refers to the structural elements, which for a
'geodesic' structure are always equilateral triangles. Ever heard of
Buckminster Fuller?


But are geodesic structures usually used to enclose a space!?


Oz1...of the 3 twins.

I welcome you to crackerbox palace,We've been expecting you.

Hull structural grids
 

DSK wrote:

Wrong. The term 'geodesic' refers to the structural elements, which for a
'geodesic' structure are always equilateral triangles.

well there you have it from the expert. Now wait, what about this one:

http://www.bfi.org/slideshtml/imag0023.htm

or this one:

http://www.bfi.org/slideshtml/imag0051.htm

or even this

http://www.bfi.org/slideshtml/imag0015a.htm

As I said, geodesic means circular. Look it up!

Bwhahhahahahaha

Cheers MC

Hull structural grids
 

Good lord!

Bogus too!

RB


"The_navigator©" wrote in message
...
The erronious idea that lots of boats were built with a "geodesic grid
inside them that completely obstructs the cabin" has been raised by DSK.

A geodesic structure is usually one which encloses a space -such as a
dome. The term geodesic refers to the great circle in geometry and
typically the circle is used to define a dome which forms a thin shell.
Thin shell hull reinforcing would be of no use in hull design as the key
to stiffness is to increase the inertial moment of the hull surface
without increasing weight. This explains why space frames and trusses
and 'structural grids' (a type of 3D truss) are used quite widely. You
may not realise it, but a foam cored sandwhich is also a 3D truss with
the bubbles forming the space between webs. The racing yacht designs
that incorporate these structures would not allow them to completely
obstruct the cabin as there would be no place to pack sails etc. In any
case, to do that would move hull material to the center of the hull
where it would be of less value in limiting hogg/sag etc. (compared to
increasing material on the far hull side).

It follows that there is an optimum hull thickness for any particulr
construction method. At design extremes where the hull is all truss with
a fabric coating we approach the design of the Zepplin. At another
extreme we see the submarine where closely spaced ring girders reinforce
the pressure hull and help reduce hull compression with depth.

Cheers MC

Hull structural grids
 

Capetanios Oz wrote:


But are geodesic structures usually used to enclose a space!?

Often, yes. But many others are just an open framework. I think I see the
problem here... Navvie© pictured a small dome house inside a boat, and said to
himself 'that can't possibly be.'

The term 'geodesic' is defined by the shape & relationship of the structural
elements, not by wether it encloses a space. Geodesic structures were invented
by Buckminster Fuller, whose career is worth some study if only for
entertainment value, and he also created the word itself.

DSK