Re: New ideas

[shawl@torchlake.com (Jonathan Shawl)]

> I have my own ideas/dreams of a double hull, thin walled with structural
> honeycomb between the two hulls.  Look at cardboard closeup and imagine a
> round tube.  The honeycomb gives it ridgidity.  Otherwise you'd have two
> floppy pieces of paper.  If you had a 4 inch space between two hulls filled
> with strong perpendicular honeycomb you might end up with a hull crush strengh
> of something simular to solid metal 1 inch thick with less than 1/2 the
> weight.  Almost like a continuous reinforcement ring...   An engineer could
> play with the numbers (I just picked them out of my head).   Just an idea that
> I'm sure someone has had before.
> Ok Chuck, your turn!
> Gene

  I also have some questions for you to think about , relating to your above idea.

>From a strength only point of view only, it most likely would be stronger per lb.
Are you planning to make it fly also? What you described sounds like the type of
construction I have seen on some space craft fuel tanks and on  control surfaces
for hi tech titanium skinned fighter bombers.
What is the savings in a lighter more complicated hull when you will most likely
just have to add more lead weight?
Even on Alvin, a very deep diving sub that is overweight with its pressure Hull:
208 cm (82 in.) OD, 4.9 cm (1.9 in.) thick titanium hull, good to a operating
Depth: 4,500 m (14,764 ft.) they just add syntactic (noncompressable) foam
flotation blocks to keep it afloat. It must be cheaper to do it that way, rather
than trying to build a lighter hull.
What about the high stress points and hull penetrations?
What about water between the layers? What about hidden rust?
Would it have to be made with many small sections welded together to make anything
like a cardboard structure?
What about the extra labor to build?
In the end, I think a thinner single wall hull with a lot of  T- ribs gives you
the most strength per lb. and you can put much equipment between the ribs. My
friend that has the 14000 lb 3 man sub with a diesel in it, made his fuel tank by
sealing up the space between 3 ribs and putting a pressure proof filler cap on the
outside. I liked his idea.
That is what is done on our large military subs.
Jon Shawl