[PSUBS-MAILIST] Titan submersible missing at Titanic site

Fri Jun 30 15:05:40 EDT 2023

Particularly in light of the fact that, as River pointed out, non-standard geometries can be acceptable under PVHO-1, but require an expensive series of destructive tests to do so, whereas the standard geometries are well proven and compliant to class if you follow the guidelines. As we have seen, OceanGate did not seem predisposed to extensive verification testing. I also wonder about what sort of visual abberation / lens effect you would get from a window with one convex face and one flat face?

With regard to the salvage, I wonder if the port was still intact when they found it, and was subsequently either destroyed or removed in order to facilitate handling of the end cap? Titanium (assuming ASTM B265 Grade 5 per the ABS rules, but who knows?) is only weakly paramagnetic, so a magnetic clamp isn't going to work, and absent any preexisting and accessable lifting lugs / shackles they would probably have had to clamp the head edge with a manipulator and then drop it in a tray for the ascent, or attach a pipe clamp to an edge, or sling it through the viewport opening as some of the surface video shows.

Sean

-------- Original Message --------
On Jun. 30, 2023, 12:30, Jon Wallace via Personal_Submersibles < personal_submersibles at psubs.org> wrote:
Sean,

My understanding was similar to River's that the viewport was a non-standard PVHO design. It sort of looked to me like a solid piece, convex on exterior and flat on interior but I can't really tell from online photos alone.

A properly certified spherical segment or even flat conical was not a huge engineering obstacle to overcome for Titanic's depth. Makes you wonder why they didn't go that route, assuming they didn't.

Jon

On Friday, June 30, 2023 at 12:02:28 PM EDT, Sean T. Stevenson via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

That will be a spherical sector window with conical bearing surface. You can kind of see the inside surface abberation if you look closely at the window in your video (0:12 - 0:18). Certainly, a window with spherical outer face and flat inner face is not a standard geometry in any reference.

The spherical sector window with conical face is a superior geometry because all points of the window are exclusively in compression. This is why PVHO-1 gives such windows a 20 year base service life, as opposed to 10 years for square edge or flanged.

Sean

-------- Original Message --------
On Jun. 30, 2023, 09:05, Jon Wallace via Personal_Submersibles < personal_submersibles at psubs.org> wrote:

According to an article I found the viewport diameter was 53cm which I believe was the outside dimension. Based upon a video I found with Rush putting his hand up to the inside viewport I would estimate the inside diameter closer to 300mm. The seat appears conical however the viewport had a convex outside surface. Hard to say if that means it was just a regular spherical segment with conical seats or a conical viewport with a convex exterior surface.

https://www.insider.com/titan-missing-submersible-photos-interior-exterior-dock-launch-2023-6#the-titans-viewport-measured-21-inches-according-to-oceangate-thats-the-biggest-viewport-of-any-deep-diving-submersible-6

https://www.youtube.com/watch?v=ClkytJa0ghc (See 0:13 to 0:29)

Jon

On Friday, June 30, 2023 at 10:07:33 AM EDT, 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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