[PSUBS-MAILIST] Titan submersible missing at Titanic site

Mon Jun 26 09:33:15 EDT 2023

 Hi Mark,We do not find air pockets, in most cases the concrete is vibrated.  I think the issue is aggregate segregation.  Before concrete pumps, long chutes  witch will allow the aggregate to separate from the mix.  This common with those mixer trucks that mix on the spot also.Hank
    On Monday, June 26, 2023, 04:52:54 AM MDT, Marc de Piolenc via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

When you encounter an easy-to-cut section of concrete, do you find a void there (air bubble) or a place where the concrete exists, but has stratified of been allowed to dry before setting?

Marc de Piolenc

 On 6/26/2023 12:16 AM, hank pronk via Personal_Submersibles wrote:

 Alec. The Swiss sub was concrete with a slip form method.  I think Farrow cement is troweled onto a mesh frame.  I was pretty intrigued by this also. A conversation with Sean made me change my mind.  Although concrete structures under water have a good track record, the chance of a weak spot is too great.  My business includes concrete cutting, and often when cutting we hit spots that cut much easier within the same pour.   Hank 

 Sent from my iPhone 

On Jun 25, 2023, at 9:08 AM, Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

  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.  
  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! 
  Best, Alec  
  On Sun, Jun 25, 2023 at 8:35 AM Marc de Piolenc via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

That's it. I lost interest when I realized he had built a superstructure on a conventional pressure hull.

Very sorry  to hear about Brian Cox.

Marc

 On 6/25/2023 6:11 PM, Jon Wallace via Personal_Submersibles wrote:

  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.  http://www.subdb.info/cgi/database/showvessel/index.cgi?ID=1272980224&VN=Esmae&VT=1 
  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. 
  Jon 

      On Sunday, June 25, 2023 at 04:09:00 AM EDT, Marc de Piolenc via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  

   I know. I fell in love with FC for yachts, which made me wonder how 
 useful it would be for pressure hulls... Turns out there is a 2010 
 exchange of messages in my archive with somebody on this list who built 
 in FC, Brian Cox. Is he still there?

 Marc

 On 6/24/2023 8:27 PM, Bernie Hellstrom via Personal_Submersibles wrote:
 > Many boat hulls were made with FC. Even the landing barges in the ww2 , to make piers to in load ships!
 >
 > Sent from my iPhone
 >

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