Re: Visibilty / Safty or Safty / Visibilty ?

[shawl@torchlake.com (Jonathan Shawl)]

Hi Rick and all subbers,
This is Jon Shawl in Michigan.
I wanted to respond to you personally Rick about your posting below, but when I got done
I decided it would be better to post it to Psubs so all can benefit from it (I hope).
It is not aimed at Rick he just triggered me into writing. I just want to help.
I do not want to flame anyone or step on any toes so please don't anyone take it that
way.
I don't want to squash creativity, but rather keep subbers from getting squashed.
I just want every one to be safe, live long, and get a chance to go diving in a safe sub
someday.
With that in mind read on.....

> Parts of what Rick Lucertini wrote:

> Is it my imagination (vivid always!) or is onboard visibility secondary to all
> engineering function?

     I would have to say no in one case. Read on before you jump to conclusions.
I know of a sub built by 2 engineers that had a lexan 3' dia .25" thick bubble view ports
on the ends of their sub.
I saw photos of the sub and my friend saw the sub at a boat show in Detroit. They were
taking orders to sell them.
The next thing I hear about them was on the news, the front viewport  imploded at 30' in
a 50' lake. Only 1 survived!
this happened about 50 miles from my home. It really had me shook up and every one
thought it was me!
How could this happen to 2 trained engineers? I figured out the total pressure that was
on that view port at 30' was about the same as a fully loaded school bus. The American
Society of Mechanical Engineers (ASME) has a report called (PVHO) Pressure Vessels for
Human Occupancy. Every one that is thinking about building a sub should get a copy. I
bought a copy long ago. It covers view port design, hatches, and hull penetrations. In
it, they do not approve of any material other than cast Acrylic (Plexiglas) and they do
not approve of any view port less than .5 in thick regardless of Dia. The method of
mounting the builder chose was not an approved design. If they would have read this
report I think he would still be here today.
No mater what size view port you want, you can not get around engineering function!

> Please, don't get me wrong.  There are those that have DONE with whatever choices
> they felt comfortable making.  I am not yet in that league myself.  They have subs -
> I don't.

How comfortable is a dead person?
Just because a person is comfortable with their own design choices doesn't mean they will
have a safe sub.
I see a lot of photos of subs I would never dive in, like fiberglass hulls, conning
towers with flat sides or square hatches.
Subs with airplane canopies or with thin or large view ports. This is why, when I was in
my teens and thought I knew what I was doing, I build a sub I felt comfortable with. I
just knew it was strong enough for about 30'. I successfully used it in my 12' deep pond
at home. Later it crushed in a unmanned test at 15 feet, and it did go BANG! That was too
close! I fixed it up and  made it into a surface boat that looks like a sub.  After about
3 years of learning more, I moved on and did it right, by the books!

> But, my passion is vis.  A tiny viewport that really forces me to stick my nose
> against the port sort of, well, defeats MY reasons for building a sub in the first
> place.  Our waters up here often have well over 110 feet of vis with loads of BIG
> marine life, kelp, etc.  I love being surrounded by hundreds of schooling fish or
> watching sea lions come up for a peek, or eels swimming up for a look.  INTERATIVE is
> the word I'm looking for.

I would love to have a large view ports in my sub. It was a lack of funding and my desire
to stay alive that limited me to a 8" X 1.25" thick flat view ports. Rick I would love to
bring my sub to your neighborhood waters with 100' vis. and take you for a dive in my
sub, that would be awesome! I would even let you press your nose up against my tiny 8"
view ports so you can get a better view. :-)

Everybody keep in mind that on a 100' dive in my sub you are safely looking out at 2350
total pounds (the weight of a large car) of water pressure  just on the view port.  And
on the hatch is another 23,500 total pounds off water trying to get in! (the weight of a
small house) My entire sub sees about  676,800 total pounds of water trying to crush it
at that depth.  I think that is about the weight of 3+ diesel locomotives or 338 tons!
The pressure is awesome and meaningless unless you know how to apply it to your proposed
design to see if the hull and view ports can take it safely.  I'm trying to put this in
terms that every one can comprehend because it seems to me, from reading many past
postings and some recent ones, and from viewing some web pages, that many people are
getting way to far into designing a sub without even doing the basic math to get an idea
of the pressures and stresses they are dealing with. I know from experience that some of
you are heading for the same mistake I made.

>  My ambient dry sub (currently in my backyard awaitng conversion) will have a canopy
> similar to a light aircraft.  At one point I even had  Chipmunk canopy - it was a
> little too fragile, thank you.

Rick, do you have the specs on it. I would like to see a photo of the sub, is it on the
psub site? or just e-mail one to me, thanks.

> Opinions?

That was mine. Hope it helps someone, somewhere, someday.

> [Camera falls off, writer's face drops into dramatic sidelight - turns to camera as
> if to say "Is a flame war on its way?]

As a new comer to this group, what is all this about flaming?

> Rick Lucertini
> empiricus@sprint.ca
> (Vancouver, Canada)
> "Most people die with their dreams still inside them."

In case no one has said this already....
And a few people die inside their dreams.    (Sorry but true.)

Jon Shawl, Michigan
shawl@torchlake.com
http://www.nwcis.com/submarine/