[PSUBS-MAILIST] Titan submersible missing at Titanic site

Sun Jun 25 21:18:57 EDT 2023

If the cement was troweled on, that sounds more like ferrocement than 
RC. Reinforced concrete ships, of which there are many built during both 
World Wars, had the concrete poured in and vibrated to fill voids like 
in conventional concrete structures. A weakness of ferrocement is indeed 
that bad plastering can leave voids, which is why the successful FC 
boats were almost all professionally plastered. Nowadays there are 
instruments that can find voids that are otherwise invisible, and 
materials that can be used to fill at least some of them. At the very 
least, you know what you have and can govern yourself accordingly.

What is Farrow cement? Never encountered the term...

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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