[PSUBS-MAILIST] Titans and Psubs

Sun Jul 2 19:42:23 EDT 2023

Gentlemen: Due to some rather significant  time constraints, I generally now have to sit on the sidelines as opposed to prior times when I would blab quite freely. I really miss participating in the online discussions and meetups.  There are some points in the present discussion I haven't seen addressed.  Either I missed them, or they're so obvious to us that we don't stop to consider that they might not be as obvious to those outside the community. "Submersible" is a very broad term.  The difference between our submersibles vs Titan and other Deep Submergence Vehicles is greater than the difference between a Cessna 150 and the Space Shuttle or a manned spaceship to Mars. The static pressure difference between the Cessna and the Mars ship is generally no greater than one Atmosphere. With few exceptions our submersibles dive to not more than 10 atm.  Titan and other DSV dive to 400 atm and more.  Our test pressures as a factor (percentage) of operating depth are also much greater the the DSVs.  I've made these points when responding to several private inquiries, but have otherwise been silent not wanting to draw attention to Psubs. Any sub that wants to dive at our Psubs sponsored events is required to meet the written standards we set some years back.  We have always had a robust exchange of advice both being requested and offered.  Any time someone posts an idea or description it's been regarded as an open invitation for critique.  This has saved all of us tons of time, money, and redo.  Can you imagine the benefits if Titan would have been a part of all this from the beginning of their project.  A lot of thanks is due to Jon for the tons of time and the leadership he has provided to our organization for many years even when he has had his hands full with other things.  For fear of overlooking someone if I attempted to list many others who have contributed so much for so long, I'll stop right there, but Jon has been the Daddy Rabbit of it all. Best regards to the whole bloomin' bunch,Jim  
In a message dated 7/2/2023 4:29:56 PM Central Standard Time, personal_submersibles at psubs.org writes: 
I for one don’t like the blue tooth control system. Yes very robust as proven by spoiled children throwing them in fits of rage.  I like a wired control box that sits on my lap.  No fuss no worries, I literally installed that system in my DW yesterday.  It is so simple I can do it myself with terrible electronic abilities.  Also the game controller gives the impression the sub is not a serious, well build vehicle.  Hank

Sent from my iPhone

On Jul 2, 2023, at 11:50 AM, MerlinSub at t-online.de via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

Marc, what means "Despite its heavy leftism" ? 

And how can a sounding system help you on a fiber with the elastic behaviour of glass?

Carsten

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Betreff: Re: [PSUBS-MAILIST] Titan submersible missing at Titanic site

Datum: 2023-07-02T07:01:28+0200

Von: "Marc de Piolenc via Personal_Submersibles" <personal_submersibles at psubs.org>

An: "MerlinSub at t-online.de via Personal_Submersibles" <personal_submersibles at psubs.org>

And the character assassination and innuendos are running full blast. Despite its heavy leftism, I would have expected something more like journalistic integrity from The New Yorker.

The article did reveal one fact that I had not seen, namely that the occupants had time enough to release weights before the fatal implosion. The acoustic sensors did work, but did not give sufficient margin.

The rest is essentially irrelevant but damaging floss. Endless harping about the controller, which was completely irrelevant to this accident, as the author and his informants must have known.

Marc de Piolenc
On 7/2/2023 3:53 AM, MerlinSub at t-online.de via Personal_Submersibles wrote:

The Titan Submersible Implosion Was “an Accident Waiting to Happen” | The New Yorker

Best insider description so far. 

Carsten

-----Original-Nachricht-----

Betreff: Re: [PSUBS-MAILIST] Titan submersible missing at Titanic site

Datum: 2023-07-01T12:13:41+0200

Von: "MerlinSub at t-online.de via Personal_Submersibles" <personal_submersibles at psubs.org>

An: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>

I have done the calculation again for a spherical shell sector window with conical edge 160Mpa and CF 4.

According to this, a window with 530/376 & 60° would have to be
would have a wall thickness of 161 mm - according to photos it was 140 mm at 60° or 110 mm at a 90° fit. 
A 90° window would have needed 132 mm thickness according to the code. 
Now.. 140 to 161 mm or 110 to 132 mm is not far off - and considering the window was inside straight - means there was more material there. 

I now think the window was OK from a pressure design point of view. To be precise you would need a cross-section drawing with the real geometry.

Carsten

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Betreff: Re: [PSUBS-MAILIST] Titan submersible missing at Titanic site

Datum: 2023-06-30T22:29:35+0200

Von: "MerlinSub at t-online.de via Personal_Submersibles" <personal_submersibles at psubs.org>

An: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>

If I use these 120 mm (STCP) and a CF of 4  it was good for around 1000 m. 

With 120 mm thickness it was at collapse deep. 

Carsten

-----Original-Nachricht-----

Betreff: Re: [PSUBS-MAILIST] Titan submersible missing at Titanic site

Datum: 2023-06-30T22:18:31+0200

Von: "MerlinSub at t-online.de via Personal_Submersibles" <personal_submersibles at psubs.org>

An: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>

I found a much better picture and correct the figures as follow:

Diameter hull                                   1600 mm (given) 

Diameter front porthole outside         614 mm

Diameter front porthole inside           436 mm 

But given with the outer window diamter given by Jon of just 530 I come to 

Diameter hull                                   1381mm

Diameter front porthole outside         530 mm (given)

Diameter front porthole inside           376 mm 

If I do with the 530 / 376 a little reverse enginering on a conical seat of 60°

I come to a thickness of just 120 mm for a inside and outside flat  conical frustrum window.  

According to PVHO-1-1987  t /Di = 0,348  with  t = 0,348 x 376 mm = 162 mm at 40 Mpa (4000m)

(for Short term critical presssure) 

But from Jon's picture it seems more a Sperical Sector Window with Conical Edge. and flat inside. 

The code has no figures for such a window. 

But if I use for Sherical Shell windows t/di shall 0,195 means t =  0,195 x 376 = 73 mm

To be diplomatic I just mix up the flat with the sperhical and got (162 + 73) / 2 = 117,5 mm  

(for Short term critical presssure) 

The code says if you have not a standard geometrie - you have to test 5 windows to destroy dephs 

and use the lowest failture pressure for your calculation. 

Carsten

. 

-----Original-Nachricht-----

Betreff: Re: [PSUBS-MAILIST] Titan submersible missing at Titanic site

Datum: 2023-06-30T16:11:40+0200

Von: "Antoine Delafargue via Personal_Submersibles" <personal_submersibles at psubs.org>

An: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>

Hello Carsten,  for the thickness, I read that the viewport should have been rated for 1300meters depth, so I think that the designer designed for a short term critical pressure of 5200m/52MPa, and perhaps thought it would be fine using a 1.3X margin to get to 4000m rather than the 4X margin we can find in Stachiw book and PVHO rules for low temperatures (to be checked but I believe it is 4x).  regardsAntoine
On Fri, Jun 30, 2023 at 4:03 PM MerlinSub at t-online.de via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

I check out some pictures and based on a given length of 6500mm 

I come to the following rough figures: 

Diameter hull                                   1600 mm

Diameter front porthole outside         700 mm

Diameter front porthole inside            466 mm 

(these diameters indicate that the porthole could be original designed as entrance..)

Now idear about the thickness of the acrylic 

- but will check out PHSME about standard flange angles tonight. 

Carsten

-----Original-Nachricht-----

Betreff: Re: [PSUBS-MAILIST] Titan submersible missing at Titanic site

Datum: 2023-06-30T15:31:14+0200

Von: "MerlinSub at t-online.de via Personal_Submersibles" <personal_submersibles at psubs.org>

An: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>

For me it looks like the biggest diameter porthole used in that deep. 

Has somebody here inner and outer diameter and the thickness?

Carsten

-----Original-Nachricht-----

Betreff: Re: [PSUBS-MAILIST] Titan submersible missing at Titanic site

Datum: 2023-06-29T21:11:55+0200

Von: "Jon Wallace via Personal_Submersibles" <personal_submersibles at psubs.org>

An: "Personal Submersibles General Discussion" <personal_submersibles at psubs.org>

 The pictures of Titan that I see in water show 16 bolts holding the retaining ring in place.  See attached photo.  Jon   On Thursday, June 29, 2023 at 11:49:18 AM EDT, MerlinSub at t-online.de via Personal_Submersibles <personal_submersibles at psubs.org> wrote:  
I have seen a video how they make the carbon cylinder and can imagine that the boat imploded in longitudinal direction. 

Create a massive shock wave with push the window out (not in). As I saw in another video the window was hold by only 4 bolts outside. 

All titan parts in the video seems undamaged. 

Carsten

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