that was the baker day test on bikini attol
baker was detonated 90 feet below watter ...able (the first test) was droped from a b29 ..the Uss Nevada was the target ship for able ..thay painted it bright orange ..
in that clip patway through the detonation you can see a long dark spot on the side of the colum of water ..that is the uss Arkansa ..it sank right after the test
http://www.nv.doe.gov/library/films/testfilms.aspx
that site has the video of the able and baker tests ..and a bunch of others conducted by the DOE
operation castle is a good one ..thay blew up a whole iland with that one ..left a 3 mile wide crater in the ground ..