according to NPR
The safety record of OceanGate, and the Titan's ability to withstand the pressure at depths of more than 12,000 feet, had both been called into question in recent days.
Sensors operated by the Navy detected the likely implosion of the Titan submersible hours before the U.S. Coast Guard publicly shared that it had gone missing — a revelation that means a five-day search that sparked round-the-clock media coverage may have been futile from the start.
https://www.npr.org/2023/06/23/11839...implosion-navy
It was midday Monday that the Coast Guard first tweeted that it was searching for the Titan. The 22-foot-long, Titanic-touring vessel was carrying four tourists and a pilot when it lost communication with its control ship less than two hours into its dive on Sunday, roughly 900 miles off the coast of Cape Cod.