Searchers detect ‘banging’ every 30 minutes near area where Titanic submarine vanished

 https://nypost.com/2023/06/21/titanic-submarine-searchers-detect-banging-near-area-where-submersible-vanished/

Even having a ship stationed on the surface could have gotten things moving much faster once communications were lost.

https://nypost.com/2023/06/20/missing-titanic-tourist-sub-could-be-stuck-in-famed-shipwreck-12500-feet-underwater/

However, having a rescue sub follow or at least stationed above the dive area could have really got the search & rescue process started much sooner.

https://www.dailymail.co.uk/news/article-12219255/Titan-diagram-released-OceanGate-shows-theres-room-ONE-person-extend-legs.html

https://nypost.com/2023/06/20/titanic-sub-best-and-worse-case-scenarios-for-the-missing-vessel/

https://www.dailymail.co.uk/sciencetech/article-12218675/Scary-animation-shows-deep-missing-Titanic-sub-be.html