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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I think that GL may allow it as I noticed that Carsten’s sub used I section stiffeners and his explanation is that with a full seal weld the oxygen will form a light rust initially but then the available oxygen is all used up and no further rusting will take place. Pressure vessels often have a breather hole in doubler plates possibly to eliminate pressure from the heat of welding. I don’t know if they are supposed to be welded up after the seal weld. <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hugh</span><span lang=EN-NZ style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Personal_Submersibles [mailto:personal_submersibles-bounces@psubs.org] <b>On Behalf Of </b>via Personal_Submersibles<br><b>Sent:</b> Sunday, 27 April 2014 12:58 p.m.<br><b>To:</b> personal_submersibles@psubs.org<br><b>Subject:</b> Re: [PSUBS-MAILIST] External Stiffeners<o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:black'>Sean, <o:p></o:p></span></p><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:black'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:black'>Thanks for that. It just never occurred to me that you could actually get enough penetration (without excessive warpage) to qualify. And it seems not. My doubler plate analogy notwithstanding, of course. I was thinking back to the old days when Perry used doublers. ABS put the kibosh on that, and it was a big change to install doubled thicknesses (for lift pads, for instance). We ground a few old doublers down on a couple of bells and found (surprise, surprise) rust.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:black'><o:p> </o:p></span></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-family:"Arial","sans-serif";color:black'>Vance<br><br><o:p></o:p></span></p><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:10.0pt;font-family:"Helvetica","sans-serif";color:black'>-----Original Message-----<br>From: Sean T. Stevenson via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>To: Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>><br>Sent: Sat, Apr 26, 2014 8:42 pm<br>Subject: Re: [PSUBS-MAILIST] External Stiffeners<o:p></o:p></span></p><div id="AOLMsgPart_0_07791322-6e53-49e0-8481-1268a9a8a6ca"><pre style='background:white'><tt><span style='color:black'>They are both permissible, provided that the stiffener section is<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>symmetrical, and the web to hull weld is full penetration. Vance refers<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>to a "doubler plate" which is typically a reinforcement joined by<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>perimeter welding only, which would be prohibited. Any partial<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>penetration weld joint creates an artificial crack at the interface<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>which can precipitate a failure. All of your pressure boundary welds<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>must be full-penetration and 100% NDT inspected for defects. With a<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>thick section like the posted example against the hull, you can see how<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>the acceptable technique would be difficult to accomplish, both to first<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>create the fully fused full-penetration weld and then to do your<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>subsequent 100% NDT inspection. The amount of heat you would drive into<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>the hull cylinder when welding the thick version is also apt to cause<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>more warpage / shrinkage of the joint than welding the narrow version.<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>Additionally, the purpose of the stiffener at all is to increase the<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>area moment of inertia of the combined hull / stiffener section, which<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>the version with the flange / outstand AWAY from the hull does more<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>effectively (more efficiently for the same weight of material), in<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>addition to being simpler to properly fabricate and inspect.<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'><o:p> </o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>Sean<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'><o:p> </o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'><o:p> </o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'><o:p> </o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>On 2014-04-26 15:02, Pete Niedermayr via Personal_Submersibles wrote:<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>> I have been looking at external stiffeners and I see that the figures in the <o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>ABS Hull Calculator shows them as (see Hull B pdf ) where as some subs (Curasub <o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>and Aquarius) seem to have them as (see Hull B pdf). Are they both correct ?<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>><o:p> </o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>> Thanks Pete<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>_______________________________________________<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'>Personal_Submersibles mailing list<o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'><a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a><o:p></o:p></span></tt></pre><pre style='background:white'><tt><span style='color:black'><a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><o:p></o:p></span></tt></pre></div></div></div><p class=MsoNormal><o:p> </o:p></p><p>__________ Information from ESET NOD32 Antivirus, version of virus signature database 9727 (20140426) __________<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p>The message was checked by ESET NOD32 Antivirus.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p><a href="http://www.eset.com">http://www.eset.com</a><o:p></o:p></p></div> <BR><BR>__________ Information from ESET NOD32 Antivirus, version of virus signature database 9727 (20140426) __________<BR><BR>The message was checked by ESET NOD32 Antivirus.<BR><BR><A HREF="http://www.eset.com">http://www.eset.com</A><BR> </body></html>