<table cellspacing="0" cellpadding="0" border="0"><tr><td valign="top">Hi Paul,<br/><br/>The question is anecdotal based on an off the cuff thought of upsizing the shell O.D. to 42" from 36". I am very hesitant to do this do to weight and handling issues however, several members have made a compelling rationale r/t simple comfort. At 53 I'm 6' 190 lbs and should expect that L to W ratio to change by build time! <br/><br/>I have to think a bit about the shell thickness r/t welding and corrosion issues, but Depth no more than 350'. I seem to remember a cross section drawing of a T section somewhere with a simple L/W/H relationship to shell T, but can't find it again. <br/><br/>I'll take that pdf if you don't mind. I'm not at home and won't be until later this week to do some number crunching.<br/><br/>Thanks Paul!<br/><br/><br/>Joe<a href="http://overview.mail.yahoo.com?.src=iOS"><br/><br/>Sent from Yahoo Mail for iPad</a></td></tr></table> <div
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Paul Moorhouse <paul@steel-fish.com>; <br>
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'PSUBS Member Discussion Group' <member-forum@psubs.org>; <br>
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<span style="font-weight:bold">Subject:</span>
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Re: [Member-Forum] Moment of Inertia <br>
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Tue, Mar 25, 2014 9:10:06 AM <br>
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<td valign="top"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;">Joe</span></p><p class="MsoNormal"><span style="font-size:11.0pt;">As it happens, this is my day job. I have been designing submarine pressure vessels for the last 28 years. I am sure there are others on the forum who do this but I am happy to help if you would like, and others at PSUBS should the need arise. </span></p><p class="MsoNormal"><span style="font-size:11.0pt;">Frame size and spacing is inter-related and there is no one answer. I have developed some models based on the European pressure vessel code PD5500 so running a new configuration is easy and surprisingly quick. PD5500 produces much lighter vessels than ASME VIII which is really aimed at chemical plant. In this way it is more similar to military codes but it does rely on quality assurance levels that do not generally come with home construction. So to
cater for this, you put a factor in. I apologise in advance for all of the calculations being in metric but give me info in either. </span></p><p class="MsoNormal"><span style="font-size:11.0pt;">I would need to know</span></p><p class="MsoListParagraph" style="margin-left:38.4pt;"><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D;"><span style="">·<span style="font:7.0pt;"> </span></span></span><span style="font-size:11.0pt;">Outside diameter</span></p><p class="MsoListParagraph" style="margin-left:38.4pt;"><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D;"><span style="">·<span style="font:7.0pt;"> </span></span></span><span style="font-size:11.0pt;">Shell thickness</span></p><p class="MsoListParagraph" style="margin-left:38.4pt;"><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D;"><span style="">·<span style="font:7.0pt;"> </span></span></span><span
style="font-size:11.0pt;">Shell material </span></p><p class="MsoListParagraph" style="margin-left:38.4pt;"><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D;"><span style="">·<span style="font:7.0pt;"> </span></span></span><span style="font-size:11.0pt;">Frame material</span></p><p class="MsoListParagraph" style="margin-left:38.4pt;"><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D;"><span style="">·<span style="font:7.0pt;"> </span></span></span><span style="font-size:11.0pt;">Diving depth</span></p><p class="MsoListParagraph" style="margin-left:38.4pt;"><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D;"><span style="">·<span style="font:7.0pt;"> </span></span></span><span style="font-size:11.0pt;">Length of parallel body</span></p><p class="MsoListParagraph" style="margin-left:38.4pt;"><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D;"><span
style="">·<span style="font:7.0pt;"> </span></span></span><span style="font-size:11.0pt;">Ends, hemi or 2:1 dished.</span></p><p class="MsoListParagraph" style="margin-left:38.4pt;"><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D;"><span style="">·<span style="font:7.0pt;"> </span></span></span><span style="font-size:11.0pt;">Preferred frame spacing </span></p><p class="MsoListParagraph" style="margin-left:38.4pt;"><span style="font-size:11.0pt;font-family:Symbol;color:#1F497D;"><span style="">·<span style="font:7.0pt;"> </span></span></span><span style="font-size:11.0pt;">Inside or outside frames</span></p><p class="MsoNormal"><span style="font-size:11.0pt;">I can send you the PDF of the work sheet as the PD5500 sums do look very pretty. </span></p><p class="MsoNormal"><span style="font-size:11.0pt;">The next step is to design the hatch penetration and I can help you here also. </span></p><p
class="MsoNormal"><span style="font-size:11.0pt;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;">This guy can thermo form your acrylic</span></p><p class="MsoNormal"><span style="font-size:11.0pt;"><a rel="nofollow" shape="rect" target="_blank" href="http://www.airesearch.nl/">http://www.airesearch.nl/</a></span></p><p class="MsoNormal"><span style="font-size:11.0pt;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;">Regards</span></p><p class="MsoNormal"><span style="font-size:11.0pt;">Paul</span></p><p class="MsoNormal"><span style="font-size:11.0pt;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;">Paul Moorhouse</span></p><p class="MsoNormal"><span style="font-size:11.0pt;"><a rel="nofollow" shape="rect" target="_blank" href="http://www.steel-fish.com">www.steel-fish.com</a></span></p><p class="MsoNormal"><span
style="font-size:11.0pt;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;"> </span></p><div class="yqt9353744289" id="yqt80034"><p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;">From:</span></b><span lang="EN-US" style="font-size:10.0pt;"> Member-Forum [mailto:member-forum-bounces@psubs.org] <b>On Behalf Of </b>Joe Perkel<br clear="none"><b>Sent:</b> 25 March 2014 03:55<br clear="none"><b>To:</b> PSUBS Member Discussion Group<br clear="none"><b>Subject:</b> [Member-Forum] Moment of Inertia</span></p><p class="MsoNormal"> </p><table class="MsoNormalTable" border="0" cellspacing="0" cellpadding="0"><tr><td colspan="1" rowspan="1" valign="top" style="padding:0cm 0cm 0cm 0cm;"><p class="MsoNormal">Where did I see the rule of thumb for T-section rib sizing relative to shell thickness? I can't seem to find it now.<br clear="none"><br
clear="none">Joe<a rel="nofollow" shape="rect" target="_blank" href="http://overview.mail.yahoo.com?.src=iOS"><br clear="none"><br clear="none">Sent from Yahoo Mail for iPad</a></p></td></tr></table></div><p class="MsoNormal"><span style="font-size:10.0pt;"> </span></p></div></td>
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