Chiseled in Stone - Fuel Cells

[protek@shreve.net]

David,
    You seem to have a much broader knowledge of concrete than I do.  And,
I think we are, for the most part, saying the same things.  But, I suggest
to anyone out there that is thinking of building a concrete sub to do the
following:  First, before a lot of debate on the fitness of the material
for hull construction has been undertaken, figure out what the minimum hull
thickness you think you would be comfortable with, and do the buoyancy
calculations on it.  If concrete is too heavy for a sub smaller than 10,000
pounds why go on.  This should be a dead issue (horsie) if you can not put
the figures to it to make it work.  I can not see ANY way it will work from
a weight standpoint, assuming that you don't want a 1.2 inch hull.  I would
not want to crawl through a drainage pipe with a 1.2 inch thickness!
    Even if a qualified engineer gave his stamp of approval to the
material, the figures for a small sub just aren't there.  I personally
think that a habitat is another question totally.
    One other thought not related to concrete;  the fuel cell idea has been
around for a while but is probably not practical for most small subs when
batteries can be used for many hours in some subs and require probably less
than 1/10 the expense.  I have been down so many of these roads before in
my design evolution over the last 30 years.  Psubbers would get a big laugh
out of some of my early ideas for sub power.  But I will not go into it
now.  The point that I am making is simple; if someone is going to build a
sub, especially for the first time, do not go off on a tangent in favor of
technology beyond the cutting edge.  Focus on tried and true techniques
that are known to work.  After experience you may want to move into newer
technology.

Gary Boucher


At 07:36 PM 3/22/99 EST, you wrote:
>Gary Boucher wrote:
>
>>Once again, as I have said many times, all of this should be
>>supervised by a qualified professional engineer for safety sake.  I
>>doubt that there are many professional engineers that would sign
>>off on concrete for a sub.  I know a prof at Louisiana Tech that is
>>in the Civil Engineering section.  I would love to hear what this
>>P.E. would say about this issue.  I think if any engineer would
>>support the concept it would be a civil engineer.  
>
>
>
>In addition I would recommend anyone considering using concrete
>for should read the authoritative references I have included in
>previous postings.   Before I spend the money on a professional
>engineer, I would want to have a well documented plan.  Concrete
>pressure hulls are similar to underwater tunnel construction. 
>However, there must be a qualified engineer somewhere in the
>world who has thoroughly researched concrete pressure hulls for
>habitats and submersibles.
>
>
>David  Irons
>
>