<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Hi Jim,</div><div>Yes you are right.</div><div>I used feet as an illustration, where they use metric pressure</div><div>in their table. </div><div>I like their scale system, because if you are building for a</div><div>shallow depth, with a thin sectioned hull, then any small margin of</div><div>error will have a bigger impact than on a thicker hull.<br>As a simple illustration, if you were building 3mm thick & ended up</div><div>2 mm that's a 33% error, whereas if you built 10mm thick & were out</div><div>by the same 1mm, that's only a 10% error.</div><div>Alan<br>Sent from my iPad</div><div><br>On 7/12/2013, at 5:11 AM, Jon Wallace <<a href="mailto:jonw@psubs.org">jonw@psubs.org</a>> wrote:<br><br></div><blockquote type="cite"><div>
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Jim,<br>
<br>
Yes, there's certainly a point in all brackets where it would
behoove the owner to bump up the nominal dive depth (operating
depth) to take advantage of lower ratios. I believe ABS uses a
static 1.25 ratio for all vessels regardless of operating depth.
GL would appear to be more conservative than ABS in this category.<br>
<br>
Jon<br>
<br>
<br>
On 12/6/2013 6:03 AM, <a class="moz-txt-link-abbreviated" href="mailto:jimtoddpsub@aol.com">jimtoddpsub@aol.com</a> wrote:<br>
</div>
<blockquote cite="mid:8D0C089FFCC7BE8-47C-12A19@webmail-d298.sysops.aol.com" type="cite"><font color="black" face="arial" size="2">
<div><font style="background-color: transparent;" face="Arial,
Helvetica, sans-serif" size="3">Hi Alan,</font></div>
<div> </div>
<div><font size="3">If I understand the requirements correctly,
then for designed maximum operating depths of 320 feet and
the 340 feet respectively the test depths would be as
follows:</font></div>
<div><font size="3">320' x 1.4 = 448' test depth</font></div>
<div><font size="3">340' x 1.25 = 425' test depth</font></div>
<div> </div>
<div><font face="Arial, Helvetica, sans-serif" size="3">And the
designed collapse depths would be:</font></div>
<div><font size="3">320' x 2.4 = 768' collapse</font></div>
<div><font size="3">340' x 2.0 = 680' collapse</font></div>
<div> </div>
<div><font size="3">Therefore if my designed operating depth is
near the lower limit <font face="Arial, Helvetica,
sans-serif">of a bracket, increasing the stated operating
depth enough to push it into a deeper bracket would
actually <em>lessen</em> </font>the requirements for
test depth and collapse. Do I understand correctly?</font></div>
<div> </div>
<div><font size="3">Thanks,</font></div>
<div><font size="3">Jim</font></div>
</font><br>
</blockquote>
<br>
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