ROVs or Remotely Operated Vehicles are quickly making many
submarines obsolete. ROV's and provide better visibility, go
deeper, go faster, go inside wrecks, cost a small fraction of what
it cost to build and maintain a submarine and if something go
seriously wrong; nobody dies.
"Bob" is an easy to build ROV that can go down to 60 feet. It
uses off-the-shelf PVC parts, arcade joystick, an underwater camera
and bilge pumps, so it is easy to build in a weekend or two.
If you want to upgrade Bob to using more powerful thrusters with props instead of bilge pumps, but you still want the ease of joystick control then see the Joystick for Props page. The Waterproofing and Scanning Sonar page may give you some more ideas too.
Bart - Argonaut Jr's Underwater ROV
Bart is a work in progress. Bart is considerably more complex and expensive than Bob, but like Bob, Bart uses off-the-shelf parts so it is quick to build.
Read more: Bart - Argonaut Jr's Underwater ROV