<font color='black' size='3' face='Arial, Helvetica, sans-serif'><font class="Apple-style-span" size="3">Joe,</font>
<div><font class="Apple-style-span" size="3"><br>
</font></div>
<div><font class="Apple-style-span" size="3">Consider using an elliptical head back there, for starters. You aren't building for much depth here, so the K-350 size will be fine (.375" ish). The ellipses are cheaper, do the same job, and give you a touch more inside room. </font><span class="Apple-style-span" style="font-size: medium; ">Then I would have a cone rolled with a short flange on the major diameter, maybe a couple of inches, to match the hull OD.</span></div>
<div><span class="Apple-style-span" style="font-size: medium; "><br>
</span></div>
<div><span class="Apple-style-span" style="font-size: medium; ">The Nekton cone-to-dome caused a pinch point that was always a hassle to clean and paint, and ultimately left some pitting in the pressure hull that had to be weld-repaired. A short cylinder on the sheet metal would give you a little more room under there to sandblast and paint during assembly and later for overhauls. I would say for maintenance a couple of flush-mount, gasketed panels in the tank would serve you well. Don't make them too ornery to remove or you won't do it as often as you will wish you had.</span></div>
<div><span class="Apple-style-span" style="font-size: medium; "><br>
</span></div>
<div><span class="Apple-style-span" style="font-size: medium; ">I'm wondering now about my own boat and using tanks like that. Is there anyone in the group who can plug and chug a metacentric height on Nekton tanks installed on a K-350? Assembly would be so simple that way. And it would tow better, which is always a good thing. The Nektons roll a bit, but are reasonably stable. A K with the pods should have plenty of weight down low. Hmm. Would it work? I'm thinking yes. Anybody else have an opinion on that?</span></div>
<div><span class="Apple-style-span" style="font-size: medium; "><br>
</span></div>
<div><span class="Apple-style-span" style="font-size: medium; ">Vance</span></div>
<div><br>
<br>
<div style="font-family: helvetica, arial; font-size: 10pt; color: black; ">-----Original Message-----<br>
From: Joe Perkel via Personal_Submersibles <personal_submersibles@psubs.org><br>
To: personal_submersibles <personal_submersibles@psubs.org><br>
Sent: Sun, May 4, 2014 12:28 am<br>
Subject: Re: [PSUBS-MAILIST] Terminating a conical transition<br>
<br>
<div id="AOLMsgPart_2_24b52d09-8575-4313-996b-674eccc3df12">
<table cellspacing="0" cellpadding="0" border="0"><tbody><tr><td valign="top">Vance,<br>
<br>
Rethinking that aft assembly to make it all soft tanks aft of a hemi head ala Nekton.<br>
If I go weld-on to the head ala Nekton, how best to attach to the head to allow for periodic access and maintenance?<br>
<br>
Joe<a target="_blank" href="http://overview.mail.yahoo.com?.src=iOS"><br>
<br>
Sent from Yahoo Mail for iPad</a></td></tr></tbody></table>
<div id="_origMsg_">
<div>
<br>
<div>
<div style="font-size:0.9em">
<hr size="1">
<b>
<span style="font-weight:bold">From:</span>
</b>
via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>; <br>
<b>
<span style="font-weight:bold">To:</span>
</b>
<<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>>; <br>
<b>
<span style="font-weight:bold">Subject:</span>
</b>
Re: [PSUBS-MAILIST] Terminating a conical transition <br>
<b>
<span style="font-weight:bold">Sent:</span>
</b>
Sat, May 3, 2014 2:03:36 PM <br>
</div>
<br>
<table cellspacing="0" cellpadding="0" border="0">
<tbody>
<tr>
<td valign="top"><font color="black" size="3" face="Arial, Helvetica, sans-serif"><font class="Apple-style-span" size="3">Joe,</font>
<div><font class="Apple-style-span" size="3"><br>
</font></div>
<div><font class="Apple-style-span" size="3">It seems like an expensive and complex assembly for what you get. Why not close the aft segment in a simpler way and fair the stern to the shape you prefer? A hemisphere with an extended shaft housing to put the prop where you want it, for instance.</font></div>
<div><font class="Apple-style-span" size="3"><br>
</font></div>
<div><font class="Apple-style-span" size="3">Vance<br>
</font><br>
<br>
<div style="font-family:helvetica, arial;font-size:10pt;color:black;">-----Original Message-----<br>
From: Joe Perkel 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, May 3, 2014 8:17 am<br>
Subject: Re: [PSUBS-MAILIST] Terminating a conical transition<br>
<br>
<div id="AOLMsgPart_2_e3b58fe4-0613-4178-ba6e-3a30c63d5a1c">
<div class="aolReplacedBody">
<div style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:14pt;">
<div><span>Sean,</span></div>
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:18.66px;font-style:normal;background-color:transparent;"><span><br>
</span></div>
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:18.66px;font-style:normal;background-color:transparent;"><span>Yes, a bolted flange with O ring.</span></div>
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:18.66px;font-style:normal;background-color:transparent;"><span><br>
</span></div>
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:18.66px;font-style:normal;background-color:transparent;"><span>I've attached an image of what's on my mind. This hull is 36" OD, cylinder length is 120". Anything bigger in diameter, simply gets way to big and bulky for handling.</span></div>
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:18.66px;font-style:normal;background-color:transparent;"><span><br>
</span></div>
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:18.66px;font-style:normal;background-color:transparent;"><span>I'm thinking at this size, I must bolt at least two hull sections together for outfitting and maintenance, and the cones can be un-stiffened or perhaps only at the joints.</span></div>
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:18.66px;font-style:normal;background-color:transparent;"><span><br>
</span></div>
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:18.66px;font-style:normal;background-color:transparent;"><span>Joe</span></div>
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:18.66px;font-style:normal;background-color:transparent;"><span><br>
</span></div>
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:18.66px;font-style:normal;background-color:transparent;"><span><br>
</span></div>
<div class="yahoo_quoted" style="display:block;">
<div style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:14pt;">
<div style="font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12pt;">
<div dir="ltr"> <font face="Arial" size="2"> On Friday, May 2, 2014 9:50 PM, Sean T. Stevenson via Personal_Submersibles <<a rel="nofollow">personal_submersibles@psubs.org</a>> wrote:<br>
</font> </div>
<div class="y_msg_container">
<div id="yiv8140311586">
<div>
<div dir="ltr">Each cone section in that case is considered alone, so if you were using stiffeners, you would need a heavy stiffener at every joint. Depending on the size, it may be simpler to use unstiffened geometry for such an assembly.</div>
<div dir="ltr">The rules do not address bolting pressure hull sections together, but I don't see why you couldn't, provided you meet the requirements in terms of the stress analysis under the maximum combined loading conditions, which are prescribed in the ABS rules. Might require some FEA to be sure. You're thinking an O-ring groove seal? Or other arrangement? I think an ASME code compliant flange would be a good place to start, but I would make sure that the cross-sectional area of each half of the flange considered individually met the requirements of a heavy stiffener per ABS, at a minimum material location (bolt hole). I would also be inclined to use SuperBolts for the connection. </div>
<div dir="ltr"><a rel="nofollow" target="_blank" href="http://www.nord-lock.com/superbolt/multi-jackbolt-tensioners/">http://www.nord-lock.com/superbolt/multi-jackbolt-tensioners/</a></div>
<div dir="ltr">Sean<br>
</div>
<br>
<br>
<div class="yiv8140311586gmail_quote">On May 2, 2014 6:03:21 PM MDT, Joe Perkel via Personal_Submersibles <<a rel="nofollow">personal_submersibles@psubs.org</a>> wrote:<blockquote class="yiv8140311586gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;padding-left:1ex;border-left-color:rgb(204, 204, 204);border-left-width:1px;border-left-style:solid;">
<table border="0" cellspacing="0" cellpadding="0"><tbody><tr><td valign="top">Sean,<br>
<br>
Would the heavy stiffener rule apply equally to several cone segments stepping down at different angles?<br>
<br>
Also, do ASME pipe flange specifications translate equally to bolted pressure hull sections? Have I missed a section somewhere on bolted cylindrical sections?<br>
<br>
Very helpful Sean thank you!<br>
<br>
Joe<a rel="nofollow" target="_blank" href="http://overview.mail.yahoo.com/?.src=iOS"><br>
<br>
Sent from Yahoo Mail for iPad</a></td></tr></tbody></table>
<div id="yiv8140311586_origMsg_">
<div>
<br>
<div>
<div style="font-size:0.9em;">
<div class="hr" style="margin:5px 0px;padding:0px;border:1px solid rgb(204, 204, 204);height:0px;line-height:0;font-size:0px;"></div>
<b>
<span style="font-weight:bold;">From:</span>
</b>
Sean T. Stevenson via Personal_Submersibles <<a rel="nofollow">personal_submersibles@psubs.org</a>>; <br>
<b>
<span style="font-weight:bold;">To:</span>
</b>
Personal Submersibles General Discussion <<a rel="nofollow">personal_submersibles@psubs.org</a>>; <br>
<b>
<span style="font-weight:bold;">Subject:</span>
</b>
Re: [PSUBS-MAILIST] Terminating a conical transition <br>
<b>
<span style="font-weight:bold;">Sent:</span>
</b>
Fri, May 2, 2014 11:45:11 PM <br>
</div>
<br>
<table border="0" cellspacing="0" cellpadding="0"><tbody><tr><td valign="top">
<div dir="ltr">2:1 semi-elliptical heads are usually fabricated with some length of straight flange (tangential cylindrical section) beyond the axis of the ellipse. Hemispherical heads may or may not have a straight flange section, but in either case are permissible to use adjacent to conical sections, provided all other requirements are met. For stiffened cones, you must have stiffeners meeting the "heavy stiffener" criteria at both ends, as close as practicable to the cone-to-cylinder and cone-to-head transitions. For unstiffened cones, the length L_c used in overall buckling calculations must be the total length between the next heavy stiffener to either side of the entire compartment length, or between the 40% of head depth points if otherwise unbounded. Cone to head welds are done in the same manner as cone to cylinder welds, and if your
head is supplied w!
ith a
flange, it is the same
thing.</div>
<div dir="ltr">Sean<br clear="none">
</div>
<br clear="none"><br clear="none">
<div class="yiv8140311586yqt0441202464" id="yiv8140311586yqt18831">
<div class="yiv8140311586gmail_quote">On May 2, 2014 2:48:52 PM MDT, Joe Perkel via Personal_Submersibles <<a rel="nofollow">personal_submersibles@psubs.org</a>> wrote:<blockquote class="yiv8140311586gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;padding-left:1ex;border-left-color:rgb(204, 204, 204);border-left-width:1px;border-left-style:solid;">
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:14pt;background-color:rgb(255, 255, 255);">
<div id="yiv8140311586">
<div>
<div style="color:rgb(0, 0, 0);font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:14pt;background-color:rgb(255, 255, 255);">
<div id="yiv8140311586yui_3_13_0_1_1399062090988_3073">I have spotted the ABS diagrams and specifications for re-enforcement and butt welds at conical to cylinder transitions. I am somewhat unclear however as to terminating at the head.</div>
<div id="yiv8140311586yui_3_13_0_9_1399062090988_6"><br clear="none"></div>
<div id="yiv8140311586yui_3_13_0_9_1399062090988_7">For example, the diagrams in the 2014 ABS underwater vehicles and hyperbaric chamber publication shows conical transitions either bordered by a cylinder at either end, or simply open at the small end???</div>
<div id="yiv8140311586yui_3_13_0_9_1399062090988_9"><br>
</div>
I want to terminate the small end of a conical transition directly to a small diameter hemi-head without another straight section, but I am unclear as to whether or not that is acceptable
in practice.</div>
<div id="yiv8140311586yui_3_13_0_9_1399062090988_12"><br clear="none"></div>
<div id="yiv8140311586yui_3_13_0_9_1399062090988_13">Joe</div>
</div>
</div>
</div>
</blockquote></div>
</div>
<pre class="yiv8140311586k9mail"></pre>
<div class="hr" style="margin:5px 0px;padding:0px;border:1px solid rgb(204, 204, 204);height:0px;line-height:0;font-size:0px;"></div>
<br clear="none">Personal_Submersibles mailing list<br clear="none"><a rel="nofollow">Personal_Submersibles@psubs.org</a><br clear="none"><a rel="nofollow" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" shape="rect">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br clear="none"></td></tr></tbody></table>
</div>
</div>
</div>
<pre class="yiv8140311586k9mail">
<div class="hr" style="margin:5px 0px;padding:0px;border:1px solid rgb(204, 204, 204);height:0px;line-height:0;font-size:0px;"></div>
<br>
Personal_Submersibles mailing list<br>
<a rel="nofollow">Personal_Submersibles@psubs.org</a><br>
<a rel="nofollow" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br>
</pre></blockquote></div>
</div>
</div>
<br>
_______________________________________________<br>
Personal_Submersibles mailing list<br>
<a rel="nofollow">Personal_Submersibles@psubs.org</a><br>
<a rel="nofollow" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br>
<br>
<br>
</div>
</div>
</div>
</div>
</div>
</div>
</div>
<div id="AOLMsgPart_4_e3b58fe4-0613-4178-ba6e-3a30c63d5a1c" style="margin:0px;font-family:Tahoma, Verdana, Arial, Sans-Serif;font-size:12px;color:#000;background-color:#fff;">
<pre style="font-size:9pt;"><tt>_______________________________________________
Personal_Submersibles mailing list
<a rel="nofollow">Personal_Submersibles@psubs.org</a>
<a rel="nofollow" target="_blank" href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a>
</tt></pre>
</div>
<br>
</div>
</div>
</font></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
</div>
<div id="AOLMsgPart_3_24b52d09-8575-4313-996b-674eccc3df12" style="margin: 0px;font-family: Tahoma, Verdana, Arial, Sans-Serif;font-size: 12px;color: #000;background-color: #fff;">
<pre style="font-size: 9pt;"><tt>_______________________________________________
Personal_Submersibles mailing list
<a href="mailto:Personal_Submersibles@psubs.org">Personal_Submersibles@psubs.org</a>
<a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a>
</tt></pre>
</div>
<!-- end of AOLMsgPart_3_24b52d09-8575-4313-996b-674eccc3df12 -->
</div>
</div>
</font>