@SheilaFentiman
Thank you so much for the link to this Twitter thread which is really interesting and identifies the many safety failings in the Titan and compares it with the sub James Cameron used to go to the bottom of the Marina Trench. It's a long list and the Tweeter says
Guys I am not an engineer. I'm a doctor & a pilot who used to tutor physics a decade ago. The extent of my engineering experience was watching my civil engineer father crush pre-stressed concrete as a kid. And yet these are the Titan failures I've identified. THAT'S MAD.
https://twitter.com/LadyDoctorSays/status/1671700989429297152?s=20
This was a very striking one:
"Looking at the basic descent & ascent: DCV1 descends because of >450kg of steel weights held to either side by electromagnets. To rise to the surface, the pilot flips a switch, the plates of steel fall to the ocean floor, & the foam pushes the sub skyward. This step is critical.
If the weights don’t drop, the pilot & DCV1 would be stuck at the bottom of the ocean. To ensure they function properly, engineers incorporated not one but SEVERAL backup systems:
1. If there’s a power failure or the magnets’ batteries run out, the weights will drop automatically
2. The support team at the surface can drop the weights via an acoustic command.
3. A special wire (galvanic timed release) helps connect the weights to the sub; it corrodes after ~11-13 hrs in seawater. Even if the pilot is KO'd & mothership can't communicate, the DCV1 rises
4. The pilot can power up something called a “frangibolt,” which uses heat to break the bolts that keep the weight-drop mechanism in place, thus jettisoning the whole assembly.
FOUR SEPARATE mechanical mechanisms to guarantee the DCV1 rises.
Titan had one elevator button"
^^