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</o:shapelayout></xml><![endif]--></head><body lang=NL link="#0563C1" vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal><span style='mso-fareast-language:EN-US'>Hi Sean, <o:p></o:p></span></p><p class=MsoNormal><span style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB style='mso-fareast-language:EN-US'>I agree with you that even our small subs should have a backup depth (or other vital readings) gauge. I always dive with a nice classic analoge and a digital( easy to see if you are rising or sinking) depth gauge. Eventual a scuba bottom timer on the outside. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='mso-fareast-language:EN-US'>If one is giving a strange reading you will notice immediately. <o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-GB style='mso-fareast-language:EN-US'>Br, Emile<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-GB style='mso-fareast-language:EN-US'><o:p> </o:p></span></p><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b>Van:</b> Personal_Submersibles <personal_submersibles-bounces@psubs.org> <b>Namens </b>Sean T. Stevenson via Personal_Submersibles<br><b>Verzonden:</b> maandag 20 november 2023 16:11<br><b>Aan:</b> Personal Submersibles General Discussion <personal_submersibles@psubs.org><br><b>Onderwerp:</b> [PSUBS-MAILIST] Vanguard class sub (UK) unintended depth excursion<o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'>Just read an article about an incident with a British Vanguard Class submarine that had an incident where it went far too deep, apparently as a result of faulty instrumentation. Engineers became aware of the sub's depth when they observed some backup depth instrument(s) and rectified the situation before it became a castastrophe.<br><br>Just wanted to prompt some discussion here, because PSubs don't necessarily employ robust backup systems, and at minimum, we should endeavour to ensure that all critical instrumentation is periodically calibrated to some reference standard to ensure accuracy, and also periodically verified in order to have some mechanism in place to detect malfunctioning instruments.<br><br>Backup instrumentation is a great method to achieve the latter (instrument verification), but comparing the primary and backup instruments needs to be part of SOPs. Where backups don't exist, some means of functional verification should at least be employed, if not per dive, then perhaps per trip?<br><br>This was a military sub that was almost lost because of an easily avoidable problem.<br><br>FWIW.<br><br>Sean<o:p></o:p></p></div></body></html>