I came across a radio story about a two young guys, one of whom started off by trying to sail around the world. Not sure how that turned out, but they then got hooked on a hunt for gold treasure buried in a deep pool of water within a cave. In order to look for the gold, they ended up building their own undersea remote operated vehicle. It's "open source", but they also supply a build-it-yourself kit for $900.
I have just ordered one. Possible uses (besides just having fun):
-checking anchor set
-checking why anchor won't come up
-checking for good snorkeling (I'm not Scuba)
-I'm sure many more
Anyone interested, their webpage is "openrov dot com".
No financial or other interests in the company.
SM #240 Aletes
St Augustine, FL