If RC cars, planes and helicopters are too conventional for you, try a HydroView RC submarine on for size. Controlled using a laptop or iPad from the comfort of the warm, dry deck of your yacht, HydroView will go as deep as your cable is long (75ft standard; up to 300ft available) and packs an HD camera with LED lights to document your search for lost treasure.

Read on at Aquabotix or Amazon – 4000$.