The link above has some technical stats: 2.5kt top speed from the 12V electrical drive, 58lbs weight, and a 40ft max depth.
These have been around for awhile, built I think by the Bellaqua Personal Submersibles company which seems to be defunct. I don't know how many BOBs were built but the first website listed here runs trips from Sand Key, Florida which is near Key Largo and down in the Florida Keys.
http://www.sfdj.com/bob/bob.htm [2]
Or if you're in Cancun:
the Virgin Islands:
or Ajaccio, France (on Corsica):