<html><head></head><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px"><div id="yui_3_16_0_1_1458005027530_2763"><span>Hi Sean,</span></div><div id="yui_3_16_0_1_1458005027530_2763"><span id="yui_3_16_0_1_1458005027530_3212">Thank you,</span></div><div id="yui_3_16_0_1_1458005027530_2763" dir="ltr"><span id="yui_3_16_0_1_1458005027530_3213">I intend on using a .5 inch strait fine </span>thread penetrator with o-ring seal. That is the reason for going through the hatch land. The hatch land was machined flat on the top and will accommodate the penetrator with no machining because the penetrator has the recess in it for the o-ring. Also the land is very beefy. It may be better to just buy a new penetrator with more connections. I am one wire short. As always you are big help!</div><div id="yui_3_16_0_1_1458005027530_2763" dir="ltr">Hank</div> <div class="qtdSeparateBR"><br><br></div><div class="yahoo_quoted" style="display: block;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 12px;"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div dir="ltr"><font size="2" face="Arial"> On Monday, March 14, 2016 7:22 PM, Sean T. Stevenson via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br></font></div> <br><br> <div class="y_msg_container"><div id="yiv3252464100"><div><div dir="ltr">Can you sketch or otherwise provide a picture of your idea with the hatch land? I can't quite visualize what you mean. There are some potential pitfalls, but I need to see what you're talking about.</div>
<div dir="ltr">As far as penetrators in the hull shell, the ASME Boiler and Pressure Vessel Code, Section 8, Division 2 (addressing PVHOs) refers to so-called "insignificant" penetrations as follows:</div>
<div dir="ltr">Openings of 3½ inches or smaller are considered insignificant if they are made in plate of 3/8 inch or less in thickness and their finishing connections are welded. The opening must not exceed 2-3/8 inches if the plate is greater than 3/8 inch thick. Threaded, studded, or expanded connections may not exceed 2-3/8 inches regardless of plate thickness. To qualify, the openings must be normal orientation. Two adjacent openings not exceeding the sizes listed above must have a minimum center to center distance equal to the sum of their diameters in order to remain insignificant. </div>
<div dir="ltr">Furthermore, two openings of diameters d1 and d2, in a group of three or more, must have a minimum center distance equal to 2.5 (d1 + d2) when in spherical shells or heads or (1 + 1.5 cos θ)(d1 + d2) when in cylinders or cones, θ being the angle from the longitudinal axis of the shell.</div>
<div dir="ltr">That said, I am personally hesitant to use any tapered thread (I.e. NPT) fitting in a hull shell, and would instead recommend either a welded fitting or an O-ring sealed straight thread fitting. The latter, of course, requires a pad lest the required spot face to seat the fitting reduce the local shell thickness, so your options are limited.</div>
<div dir="ltr">Sean<br clear="none">
</div>
<br clear="none"><br clear="none"><div class="yiv3252464100gmail_quote">On March 14, 2016 3:14:38 PM MDT, hank pronk via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<blockquote class="yiv3252464100gmail_quote" style="margin:0pt 0pt 0pt 0.8ex;border-left:1px solid rgb(204, 204, 204);padding-left:1ex;">
<div class="yiv3252464100yqt9221042312" id="yiv3252464100yqt53710"><div style="color:#000;background-color:#fff;font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:12px;"><div id="yiv3252464100yui_3_16_0_1_1457989721783_2466">Hi Sean,</div><div dir="ltr" id="yiv3252464100yui_3_16_0_1_1457989721783_2466">I would like to add one more electrical penetrator to my new sub and I don't want to weld in a reinforcement for the penetrator. I am thinking of drilling and threading into the edge of my hatch land . I am thinking it will not bother the strength of the hatch because it is two inches thick. Gamma has four holes drilled and threaded in the bare hull with no bushing or anything. That was certified to 1,000 feet so I figure I can do that through the 2 inch material. What do you think?</div><div dir="ltr" id="yiv3252464100yui_3_16_0_1_1457989721783_2466">Hank</div></div></div><div style="margin-top:2.5em;margin-bottom:1em;border-bottom:1px solid #000;"></div><pre class="yiv3252464100k9mail"></pre><hr><br clear="none">Personal_Submersib!
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