Voyage Data Recorder - Ship's Blackbox What is it?

[@williamlloyd3769]

Regarding Voyage Data Recorder, does automatically detach itself from the ship when it gets to a certain depth. As tough as the VDR is, doubt it has a crush depth past a 1000 feet. PS - BTW, does a VDR have a UPS that keeps it functioning should the MV loose power like the MV Dali? Will it continue to get data from the engineering space after the ship drops the plant? In other words is any data recorded during the 45-60 seconds it takes for the emergency generator to come up to speed and take over the critical load?

[@spergnation1859]

What would cause all sensor data to stop transmitting to the VDR?