The Aquabotix HydroView Sport ($3,995, aquabotix.com) remote-operated vehicle (ROV) can give you a spectacular close-up view of the underwater world while you stay dry. Drive this motorized mini submarine remotely under your boat to see bottom structure and marine life — maybe indulge in a little treasure hunting. With a 50-foot cable (extendable to 300 feet), you can operate and view the HydroView remote camera from a laptop, iPod, tablet or smartphone. Don't want to spend four grand? Try the AquaLens ($795), HydroView's little brother. It fastens to a standard boat hook and lets you watch subsurface life on a wrist-worn 3.5-inch LCD screen or suitable monitor.