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<DIV><FONT size=3>Vance,</FONT></DIV>
<DIV><FONT size=3>Is the problem with Rain-X a function of interaction with
sunlight, salt water, or ...? I recall about forty years ago there was a
paste available for use on Plexiglas aircraft windscreens, but I was reluctant
to risk using it for fear of doing it wrong and fogging up the windscreen.
It was basically a rubbing compound. Covering the windscreen when stored
outdoors to protect it from the sun was well worth it to retard crazing and
yellowing.</FONT></DIV>
<DIV><FONT size=3>Jim T.</FONT></DIV>
<DIV> </DIV>
<DIV>
<DIV>In a message dated 10/28/2014 5:12:57 P.M. Central Daylight Time,
personal_submersibles@psubs.org writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2 face=Arial><FONT
color=black size=3 face="Arial, Helvetica, sans-serif"><FONT
class=Apple-style-span size=3>Jim,</FONT>
<DIV><FONT class=Apple-style-span size=3>It seems to me that Rain-X and
acrylic aren't the best of friends. I've never used it, anyway. As a point of
interest, we had the secondary shields on all the Perry boats originally, but
with 3/4" holes top, middle and bottom, which left room to stick a hose in for
rinsing. and the holes pretty much disappeared in the water and weren't a
problem, visually. I think they used a couple of dozen screws to put them on,
so we didn't do it very often, as you might well imagine.</FONT></DIV>
<DIV><FONT class=Apple-style-span size=3>Vance<BR></FONT><BR><BR>
<DIV
style="FONT-SIZE: 10pt; FONT-FAMILY: helvetica, arial; COLOR: black">-----Original
Message-----<BR>From: via Personal_Submersibles
<personal_submersibles@psubs.org><BR>To: personal_submersibles
<personal_submersibles@psubs.org><BR>Sent: Tue, Oct 28, 2014 6:01
pm<BR>Subject: Re: [PSUBS-MAILIST] viewport questions<BR><BR>
<DIV id=AOLMsgPart_2_bb34e065-330b-4264-8c61-bd62b135c085>
<DIV class=aolReplacedBody
style="FONT-SIZE: 10pt; FONT-FAMILY: Arial; COLOR: #000000" bottommargin="7"
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face=Arial>
<DIV>Hi Alec,</DIV>
<DIV> </DIV>
<DIV>What is the average distance between the two domes? Do you have any
type of mesh etc. over the 1/4" holes to keep debris out? Do
you have some type of flushing system for cleaning the surfaces between
the two? Since that's an ambient space I'm guessing it wouldn't take too
long to remove the outer dome when you want to do a thorough cleaning.</DIV>
<DIV> </DIV>
<DIV>All: Have you been using Rain-X on your view ports and domes?
A while back I saw some ads for another hydrophobic product that claims
to be superior to Rain-X, but I don't recall the brand.</DIV>
<DIV> </DIV>
<DIV>Best regards,</DIV>
<DIV>Jim T.</DIV>
<DIV> </DIV>
<DIV>
<DIV>In a message dated 10/28/2014 4:30:30 P.M. Central Daylight Time, <A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>
writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2 face=Arial>
<DIV dir=ltr>Hi Vance,
<DIV><BR></DIV>
<DIV>Actually it starts at 2" thickness, and at the time was the thickest
dome Greg had made. It was an iffy proposition, meaning he didn't know if it
would turn into sub jewelry or just a deformed glob of expensive material.
Luckily it came out virtually perfect. </DIV>
<DIV><BR></DIV>
<DIV>My hull is 31" OD, a little smaller than yours. The window is a 120
degree segment, just under 27" OD. So the trick is how to span the gap
between the 27 inches and the 31 inches. In the original design, this bow
window also acted as a hatch, a la Deep Flight. I made a massive Al ring 31"
OD, which telescoped on linear bearings and four 1.25" bars, driven by rams.
With ensuing redesign, the need for all that disappeared because I now have
a coning tower, so I've dropped the bars and rams, and the seat is now
mounted to the hull very simply with four big bolts. It will make a very
handy big door into the sub for maintenance purposes, but is overkill and
the window could be mounted by using part of your existing endcap and a
permanently welded conventional seat. </DIV>
<DIV><BR></DIV>
<DIV>One big decision is the window seat geometry. I like conical because
PVHO rates it for twice the life of square edge, but it requires fabrication
capabilities that Greg didn't have for the window and I didn't have for the
seat. So its a square edge for the simple reason that we could make it that
way. </DIV>
<DIV><BR></DIV>
<DIV>I should mention the Al ring actually has two domes on it, one inside
the other. The 27" dome is structural, and the outside dome is 31" and only
half an inch thick. The outside one is just for fairing, to protect the
structural dome from abrasion, and to mitigate collision damage. The space
between the two domes is free flooding, and there are 1/4" holes around the
edge of the outer dome to facilitate that. In a collision, the water would
squish out through the little holes, so the thing is basically a shock
absorber.</DIV>
<DIV><BR></DIV>
<DIV>As for calculations, I will paste the window calcs below. It is really
just table lookups from PVHO tables, a simple cook book. The seat would have
to be calculated with FEA. I didn't have FEA, so I did like the Greeks and
Romans. You know why the Partenon is still standing? Try to do engineering
calculations using Roman numbers! It was too complex, so they simply made
everything massive. The seat is one integral piece of aluminum of ridiculous
proportions, and it backs into a 516 gr 70 ring on the end of the hull that
is an inch thick and two inches deep. I'm pretty confident that ring isn't
going wobbly before something else does. </DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV>Best,</DIV>
<DIV><BR>Alec</DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV><BR></DIV>
<DIV>----------------- pasted ------------------</DIV>
<DIV>
<H1><SPAN style="FONT-SIZE: 14pt">Viewport Depth Rating per
PVHO-1a-1997</SPAN></H1>
<DIV class=MsoNormal> </DIV>
<DIV>The following calculations and specifications are for a sperical sector
window with square edge, to include an optional O-ring seal.</DIV>
<DIV class=MsoNormal> </DIV>
<DIV class=MsoNormal> </DIV>
<DIV class=MsoNormal> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt">1) Determine Conversion
Factor (CF) </SPAN></DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt">Water temperature =
75 </SPAN><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Symbol">°</SPAN><SPAN
style="FONT-SIZE: 10pt">F (tropical conditions)</SPAN></DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt">From Table 2-2.4, CF = 7
</SPAN></DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt">2) Given actual
fabricated dimensions</SPAN></DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt">t</SPAN><SUB><SPAN
style="FONT-SIZE: 10pt">min</SPAN></SUB><SPAN style="FONT-SIZE: 10pt"> =
1.73”</SPAN></DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt">D</SPAN><SUB><SPAN
style="FONT-SIZE: 10pt">i</SPAN></SUB><SPAN style="FONT-SIZE: 10pt"> =
26.847”</SPAN></DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Symbol">\</SPAN><SPAN
style="FONT-SIZE: 10pt">t/D</SPAN><SUB><SPAN
style="FONT-SIZE: 10pt">i</SPAN></SUB><SPAN style="FONT-SIZE: 10pt"> =
0.064</SPAN></DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt">Entering table 2-2.10
with STCP, t/Di = 0.064</SPAN></DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt">Solving for Critical
Pressure = 3,460 psi</SPAN></DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt">Since Short Term Critical
Pressure (STCP) = CF x P = 3,460 psi</SPAN></DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt">Solving for P,
P = 3,460 / 7 = 494 psi</SPAN></DIV>
<DIV class=MsoNormal><SPAN style="FONT-SIZE: 10pt"></SPAN> </DIV>
<DIV class=MsoNormal><SPAN
style="FONT-SIZE: 10pt; FONT-FAMILY: Symbol">\</SPAN><SPAN
style="FONT-SIZE: 10pt"> Safe operating depth for window = 1,139
fsw</SPAN></DIV></DIV>
<DIV><BR></DIV>
<DIV> </DIV></DIV>
<DIV class=gmail_extra><BR>
<DIV class=gmail_quote>On Tue, Oct 28, 2014 at 3:48 PM, via
Personal_Submersibles <SPAN dir=ltr><<A
title=mailto:personal_submersibles@psubs.org
href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</A>></SPAN>
wrote:<BR>
<BLOCKQUOTE class=gmail_quote
style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid"><FONT
color=black size=3 face="Arial, Helvetica, sans-serif"><FONT
size=3>Alec,</FONT>
<DIV><FONT size=3><BR></FONT></DIV>
<DIV><FONT size=3>I hope this is still you.</FONT></DIV>
<DIV><FONT size=3><BR></FONT></DIV>
<DIV><FONT size=3>I've been talking to Greg about a major retro-fit on my
K-350--a full hull-diameter dome segment viewport in place of the forward
elliptical head. He mentioned having built yours (the 1000' version) while
we were talking about thickness and whether to try and use something out
of Pete's junk pile.</FONT></DIV>
<DIV><FONT size=3><BR></FONT></DIV>
<DIV><FONT size=3>While we were chewing the fat about this, he said that
to the best of his recollection, yours started at 1.5" thickness, and that
he could build it for me (maybe a 150 degree arc segment) for what I
thought was a very reasonable amount.</FONT></DIV>
<DIV><FONT size=3><BR></FONT></DIV>
<DIV><FONT size=3>My problem (okay, one of my problems) is that I don't
really know how to do the calculations for these things. That said, I'm
wondering if a partial copy of yours might not do the trick for my
application (it would be tested much shallower, 500 feet or
thereabouts).</FONT></DIV>
<DIV><FONT size=3><BR></FONT></DIV>
<DIV><FONT size=3>I don't know how you feel about sharing that kind of
thing, but I have a picture in my head of an acrylic bow K-350 with some
fairings and a Minn-Kota driven Deepworker style propulsion system. I
think it would make a great little boat, and so if I can get the viewport
and frame designed, then it's going to be built.</FONT></DIV>
<DIV><FONT size=3><BR></FONT></DIV>
<DIV><FONT size=3>It's time to play if I'm going to. So, what do you
think?</FONT></DIV>
<DIV><FONT size=3><BR></FONT></DIV>
<DIV><FONT size=3>Best Regards,</FONT></DIV>
<DIV><FONT size=3>Vance
Bradley</FONT></DIV></FONT><BR>_______________________________________________<BR>Personal_Submersibles
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