<div style="color:rgb(0,0,0);font-family:arial,sans-serif;font-size:12pt"><p style="margin: 0.1rem 0; line-height: 1.0;">Hi Marc,</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">that was a long time... I believe it was the unsupported/unstiffened thin wall formula (possible from C T F Ross Pressure Vessel's book). It does seem a bit high, possibly I'm mis-remembering/guessing, but I do remember it was a lot higher than expected. During concrete pouring a sample of each pour was taken, these samples would need to be tested to determine the properties of the actual concrete used. Those test results would then be used to more accurately estimate collapse depth.</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Wilfried's site is still up with some pictures and links to videos:</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"><a href="http://concretesubmarine.com/">http://concretesubmarine.com/</a></p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Thanks,</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> Ian.</p>
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<p>-----Original Message-----<br>From: Personal Submersibles General Discussion <personal_submersibles@psubs.org><br>Sent: Jun 25, 2023 6:22 PM<br>To: irox via Personal_Submersibles <personal_submersibles@psubs.org><br>Subject: Re: [PSUBS-MAILIST] Concrete hull submarine</p>
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<p>How was the crush depth calculated?</p>
<p>Marc de Piolenc</p>
<div class="moz-cite-prefix">On 6/26/2023 3:01 AM, irox via Personal_Submersibles wrote:</div>
<blockquote cite="mid:976d5bd4-c9e1-4cf7-fcdf-00c8c57b7e92@ix.netcom.com">
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<p style="margin: 0.1rem 0; line-height: 1.0;">Hi Alec,</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Yes, that's pretty much it. Wilfried Ellmer is the person who built the Swiss sub and started the one in Columbia.</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Short version:</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">The construction phase was plagued with delays, including the shipyard we'd rented space from going bankrupt (twice), and one time all the managers were arrested and led off the site in handcuffs. Each delay added months, sometimes this would use up the dry part of year delaying work until next year. Eventually the launch permit expired, also the local administrator positions were rotated (every 4 years) and the incoming administrator were not happy to hear about a submarine being built in their jurisdiction. Ultimately they refused to reissue the launch permit and asked for a large sum of money each month for 'inspections' with the vague chance they would issue a launch permit later. Work on the project stopped here.</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Shortly after that the shipyard was sold to a energy company to be used as their private ship chandlers. There was a free-n-clear clause in the sale and the concrete submarine, now sitting right at the water's edge waiting to be launched, would cause problems and potentially trigger a lawsuit. In the end I denied ownership of the sub, based on it never officially being delivered. The sub sat in the shipyard for 10+ years after that. I would periodically check on it using Google maps satellite view. Most recently the sub was replaced by a pile of rubble, so I assume it had been destroyed.</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">A few notes on the sub (from memory, so numbers might be off):</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Hull: Teardrop</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Construction: Slip cast reinforced concrete</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Length: 19meters</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Width: 4.5meters</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Operational depth: 300meters</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Crush depth: 2800meters</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Crew: 4</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Operational dive time: 1 week</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Emergency life support: 3 weeks</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Viewports: 1 bow dome, 8 small "sky-light" viewports.</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">ROV lockout chamber.</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Surface propulsion: Diesel engine</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Submerged propulsion: Electric</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Surface range: 2500 miles (not sure if that would end up being realistic)</p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Submerged range: 50 miles</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">ABS (and offshore concrete structure rules) was to be followed as much as possible, which did cause some disagreement...</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Ultimately I knew this project contained risk, and at the time I was able to accept that risk.</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">I would consider doing this again, but in the USA, and with an improved design which should be more conducive to following ABS. Ideally this would be done in away so hulls could be cheaply manufactured for destructive testing.</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> </p>
<p style="margin: 0.1rem 0; line-height: 1.0;">Cheers,</p>
<p style="margin: 0.1rem 0; line-height: 1.0;"> Ian.</p>
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<p>-----Original Message-----<br>From: Personal Submersibles General Discussion <a class="moz-txt-link-rfc2396E" href="mailto:personal_submersibles@psubs.org"><personal_submersibles@psubs.org></a><br>Sent: Jun 25, 2023 8:08 AM<br>To: Personal Submersibles General Discussion <a class="moz-txt-link-rfc2396E" href="mailto:personal_submersibles@psubs.org"><personal_submersibles@psubs.org></a><br>Subject: Re: [PSUBS-MAILIST] Titan submersible missing at Titanic site</p>
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<div dir="ltr">There's an interesting story about cement subs, which I will tell to the best of my recollection. In the early years we had a PSUBS member whose name I forget, I believe Swiss or Austrian, who had built a ferrocement sub that he kept at a mooring in a Swiss lake. The sub was successful, he dived it for years. But eventually he moved to Colombia due to marriage, and scuttled the sub in the lake, because the road he had used to take it there had been re-routed or modified somehow, leaving him without any way of getting it out. The sub became an attraction for local SCUBA divers.
<div> </div>
<div>The second part of the story is that another PSUBS member, Ian Roxborough, hired the first guy to build him a large cement sub with the intention of making it an ocean going live-aboard. The project was done completely on the level, with notification to authorities and in a major port. This was no drug sub built in the jungle. It got to the point where the hull was complete, and I think they were about for the first launch. However, Colombia being plagued by drug subs, the authorities would not sign off on final paperwork or something (can't remember the exact glitch.) Ian had sunk a ton of funds into it, and the sub was probably perfectly good, but approval never came. I'm not sure what happened to the sub. But Ian is still very much active, so maybe can tell us. I'm not sure if he's on the email list. If you are, Ian, sorry for bringing up this rather painful memory!</div>
<div> </div>
<div>Best,</div>
<div>Alec</div>
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<div class="gmail_attr" dir="ltr">On Sun, Jun 25, 2023 at 8:35 AM Marc de Piolenc via Personal_Submersibles <<a class="moz-txt-link-freetext" href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:</div>
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<p>That's it. I lost interest when I realized he had built a superstructure on a conventional pressure hull.</p>
<p>Very sorry to hear about Brian Cox.</p>
<p>Marc</p>
<div>On 6/25/2023 6:11 PM, Jon Wallace via Personal_Submersibles wrote:</div>
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<div dir="ltr">Marc, that was probably Brian Cox who passed away a year or so ago. His pressure hull was steel but he did use ferrocement for the superstructure. <a href="http://www.subdb.info/cgi/database/showvessel/index.cgi?ID=1272980224&VN=Esmae&VT=1" target="_blank" rel="nofollow noopener">http://www.subdb.info/cgi/database/showvessel/index.cgi?ID=1272980224&VN=Esmae&VT=1</a></div>
<div dir="ltr"> </div>
<div dir="ltr">There are no standards for using ferrocement as a manned submarine pressure hull and I think anyone attempting it would find little support for the project given the Ocean Gate loss.</div>
<div dir="ltr"> </div>
<div dir="ltr">Jon</div>
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<div>On Sunday, June 25, 2023 at 04:09:00 AM EDT, Marc de Piolenc via Personal_Submersibles <a href="mailto:personal_submersibles@psubs.org" target="_blank" rel="noopener"><personal_submersibles@psubs.org></a> wrote:</div>
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<div>
<div dir="ltr">I know. I fell in love with FC for yachts, which made me wonder how <br clear="none">useful it would be for pressure hulls... Turns out there is a 2010 <br clear="none">exchange of messages in my archive with somebody on this list who built <br clear="none">in FC, Brian Cox. Is he still there?<br clear="none"><br clear="none">Marc<br clear="none"><br clear="none">On 6/24/2023 8:27 PM, Bernie Hellstrom via Personal_Submersibles wrote:<br clear="none">> Many boat hulls were made with FC. Even the landing barges in the ww2 , to make piers to in load ships!<br clear="none">><br clear="none">> Sent from my iPhone<br clear="none">></div>
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