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.