Titanic tourist sub goes missing sparking search

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I've done laser scanning, of a shipyard, where we also had photogrammetry. The difference is significant.

Laser scanning is difficult to get accurate. Base point inaccuracy is what's messing up the data. But it's incredibly precise, i.e., every scan is down to small details. What you get when combining the scans is a group of 3D "point clouds", which then need to be merged and aligned manually. Photogrammetry was only good for terrain and structures, while laser scanning combined with photos and with manual post-processing allowed us to map out every pipeline, valve, cable, rail, hook.

The volume of data isn't excessively large, it was usually measured in terabytes per session. Laser scanning is monochrome, i.e. you only get one value per point (distance), and every value is significant. Photos are then used to create textures if you need presentation quality visuals.
There's also the question of "polishing the cannonball" ... how precise and accurate do you need/want the scan to be, and what details are you trying to collect?
 
Someone posted a YouTube link to one of the reported "leaked" transcripts of the submersible having difficulties ... skeptical enough not to repost, but one thing that caught my attention was that the timestamps in the video were in Eastern Daylight Time. MV Polar Prince departed from St. John's, which would be on Newfoundland Daylight Time (1.5 hours ahead of EDT). Is there any reason a vessel would not use nearest local time or local time at point of departure, or is that "spotting the thread?"
The report of screams is obviously pure hokum but I am not convinced that the transcript is. Cameron indicated he was aware that the sub had reported problems and was trying to ascend when communication was lost.
 
Here's the first half of a blog post in which OceanGate responded to questions about its failure to seek classification for the Titan. I'll include my thoughts after each paragraph:

From OceanGate | Blog | Why Isn't Titan Classed? (Retrieved from archive.org as oceangate's website is currently not responding, no doubt due to load.)

Most major marine operators require that chartered vessels are “classed” by an independent group such as the American Bureau of Shipping (ABS), DNV/GL, Lloyd’s Register, or one of the many others. These groups have assembled very detailed standards for classing everything from oil tankers to auxiliary ship equipment like Remotely Operated Vehicles (ROVs). Many of these standards are based on industry practice or covered by regulations such as reserve buoyancy, the number of life rafts, the types of materials that can be used on a hull, etc.

Good so far. Except it would be more accurate to replace the first word "Most" with "Essentially all".

Classing assures ship owners, insurers, and regulators that vessels are designed, constructed and inspected to accepted standards. Classing may be effective at filtering out unsatisfactory designers and builders, but the established standards do little to weed out subpar vessel operators – because classing agencies only focus on validating the physical vessel. They do not ensure that operators adhere to proper operating procedures and decision-making processes – two areas that are much more important for mitigating risks at sea. The vast majority of marine (and aviation) accidents are a result of operator error, not mechanical failure. As a result, simply focusing on classing the vessel does not address the operational risks. Maintaining high-level operational safety requires constant, committed effort and a focused corporate culture – two things that OceanGate takes very seriously and that are not assessed during classification.

This is an obvious attempt to confuse the reader, who we can presume is a potential customer. Operations and procedures are not the issue here. Classification is about vessel safety. Furthermore the largest part of the reason that operator error is responsible for most accidents is that classification works. Few classified vessels fail.

[Edit to include this clarification:

]

When OceanGate was founded the goal was to pursue the highest reasonable level of innovation in the design and operation of manned submersibles. By definition, innovation is outside of an already accepted system. However, this does not mean that OceanGate does meet standards where they apply, but it does mean that innovation often falls outside of the existing industry paradigm.

Straight BS. As the author of this (Rush himself?) admits in the first part of the next sentence.

While classing agencies are willing to pursue the certification of new and innovative designs and ideas, they often have a multi-year approval cycle due to a lack of pre-existing standards, especially, for example, in the case of many of OceanGate’s innovations, such as carbon fiber pressure vessels and a real-time (RTM) hull health monitoring system.

So the heart of the issue is Rush didn't want to wait for new standards to test exactly the things that failed.

Bringing an outside entity up to speed on every innovation before it is put into real-world testing is anathema to rapid innovation. For example, Space X, Blue Origin and Virgin Galactic all rely on experienced inside experts to oversee the daily operations, testing, and validation versus bringing in outsiders who need to first be educated before being qualified to ‘validate’ any innovations.

Again, deliberately misleading. There is a huge difference between testing and passenger operations. SpaceX, Blue Origin and Virgin Galactic all went through a rigorous and lengthy external validation process before carrying passengers.

As an interim step in the path to classification, we are working with a premier classing agency to validate Titan’s dive test plan. A licensed marine surveyor will witness a successful dive to 4000 meters, inspect the vessel before and after the dive, and provide a Statement of Fact attesting to the completion of the dive test plan.

Whoopee. They will provide a statement that the vessel survived one dive. This is in no way an acceptable substitute for a proper engineering evaluation. Especially with carbon fiber's known propensity to fail without warning when subjected to cyclic stresses well within its theoretical yield strength when compromised in non-obvious ways.


I'm not saying Real Engineering based his video on my post, but :)
 
This may be fabricated but it does seem somewhat credible to me.

That was the one where I noted the timestamps are in Eastern time instead of Newfoundland.
 
I doubt SOSUS would ever release the recordings. Too much information can be gathered about its positioning.
The video in question isn't purporting to be SOSUS recordings, but the text transmissions between Titan and Polar Prince. Besides the timestamp issue, it describes the sub descending at a fast rate (if anything, Titan's test dives showed it to be fairly buoyant due to the carbon fiber hull), reporting an alarm from the acoustic monitoring system on the hull, and trying to surface for 15 minutes prior to the loss of comms. While we do have thirdhand reports that the sub was attempting to surface when contact was lost, if those details were correct I would think they would have been corroborated by other accounts and they would raise questions about the search activities.
 
Is there any reason a vessel would not use nearest local time or local time at point of departure, or is that "spotting the thread?"

Yes, but I see no reason for a civilian vessel to do that.
 
Hek, all my diving is recorded in the log as GMT (well in the computer.... I don't actually log) ... If I was a boat, that's all I would ever use.
 
https://www.shearwater.com/products/swift/

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