[PSUBS-MAILIST] Titan submersible missing at Titanic site

Mon Jun 26 06:52:35 EDT 2023

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
>>>     <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>
>>>     <mailto: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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>>
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