Originally Posted by bearfoil
Why no Alvin? Three crew, 6 MkX eyeballs, 15,000 foot depth, no decompressing, visual (camera) recording, etc. She's 46 years old, but she found Titanic.
She works quickly. Just not cheaply.
Alvin was not used to find the Titanic. Titanic was found with towed side-scan and towed down-looking cameras (and by a ship based bottom sounder and a magnetometer, according to PH Nargeolet). Alvin visited for a detailed exploration in 1986, the year after the initial discovery.
Alvin is even more limited than an ROV for wide area search. It moves at 1-2knts, and can only stay on the bottom 6-10 hours out of 24. The shorter time applying to dives with long transits, like searching.