Alan,
Jon
I
think that if I was going to do this from scratch I would probably go with a
conventional tower there were a few unknowns doing this but it came out nice,
I seem to remember Mike saying this was optical grade acrylic, as for
distortion I have not noticed any yet I have been standing looking out at my
safety divers at varying distances and have seen none but I was not really
looking, the main thing I like is its big, being a large frame man( nice for
overweight ) it?s very easy for me to get in and out, as things progress I
will shoot some video from the tower and post it so you all can see, one thing
I will say Mike C did not cut any corners having the tower made it?s a very
nice piece of acrylic I wish I would have been able to build the flanges as he
had drawn then up out of titanium it was just too much money maybe after
this wreck I can spend another 250k and make the changes I want, I would like
to add that without PSUB and all its members I would not have been able to get
to this point, the knowledge here is so vast that we could do anything,
it?s so nice if you have a question go send an email and get answers covering
every aspect of your question, thanks everyone
Brian V.
Ryder
brian@subatlantic.com
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From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Alan
James
Sent: Sunday, July 11, 2010 3:23 AM
To:
personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Acrylic
cylindrical conning tower
point taken re
material specs.
I had your same
reservations re vision out of a tube.
I guess in Brian's
case it's not his primary viewing port & it will be interesting to
here his experience
if he has extended viewing through it.
I spent a bit of
time at a local aquarium trying to get a handle on viewing through
acrylic.
They had
a number of large tanks of differing thickness & shapes.One an
acrylic tunnel
100 meters long. I
was looking through at various angles to see the
distortion.
I came out feeling
slightly nauseous. I was thinking it was because my vision
was
being screwed
around a lot by the varying distortions. My fear is that you might get
that
looking up &
down through a cylinder. If you rotated your head from side to side the
distortion
Point taken Jens,
I've made that comment before re subject headings, will be more attentive in
future.
----- Original
Message -----
Sent: Sunday, July 11,
2010 6:24 PM
Subject: Re:
[PSUBS-MAILIST] pressure gauge
Standard warning here...check the specifications of
the acrylic used. If they do not meet or exceed ASME standards then
the material is not acceptable. I've observed on more than a couple
occasions that fabricators who supply acrylic for terrestrial use often use
material that does not meet ASME standards (not necessary for furniture and
decorative items, etc) and don't even know what the strength specifications
of the material is.
I have considered an acrylic conning tower,
however Stachiw says that the cylinder provides the worst optical
characteristics of any viewport configuration. It acts as an
asymmetric lens distorting the shape of images perceived by the
passenger. As the radius of the cylinder increases, the distortion is
less but that also depends upon the thickness. Stachiw wasn't too
specific and I wish he had provided more info about this issue. I've
hesitated designing around an acrylic conning tower because I don't want to
spend the money on such an expensive item only to find out the visibility
sucks. I suspect the visual distortion is more noticeable when looking
upward or downward since you are peering at an oblique angle to the material
and through more of it. Viewing perpendicular to curvature should have
the same viewing qualities as a dome. Once Bryan gets situated with
his vessel I hope he can describe any visual deficiencies, if they
exist.
Jon
On 7/10/2010 11:47 PM, Alan James wrote:
There are some
pretty big cast tubes that are done as a standard
line
that I've seen
advertised by Chinese manufacturers. Might be an inexpensive way of
doing
the conning tower
in the future
I came across
this supplier that advertises 500mm diameter & up to 40mm
thick
However the
advert is a bit confusing.
4" is a huge
thickness. I could imagine forming it would be fun- days in the oven. They'd
have to cut the
angles of the
mating surfaces first wouldn't they, then clamp & glue it round a form
wich they could remove
Brian you might
be able to control your boat from up in the conning tower. Pay a student to
interface a
remote play
station controller with your motor controls. There is heaps on the net
showing how it's done &
ready made
circuit boards to help with this.