Not sure if these have been covered before but Navy films for SeaLab 1, 2 and 3 are in public domain and available for free. There is a service that sells these and others (Periscope Film) but they put a time bar in the middle. The public domain copies straight from the Navy do not have this bar. You can also find versions of these on YouTube.
Movies:
Watch the public domain movie of SeaLab 1
http://archive.org/details/SealabI
100 fathoms deep: SeaLab III (1971)
http://archive.org/details/cus_00007
Go here and get a list of all SeaLab movies (seaLab 1, 2, 3)
http://archive.org/search.php?query=sealab AND mediatype%3Amovies
Once here search under water, diving, Cousteau, etc.
I save the films to my computer and view them using VLC (it will paly anything, is free, and is add free and virus free).
http://www.videolan.org/index.html