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
|
|