how long can i drive it for?
JAMES B the torpedo 3500 will last you about 50min on a full charge. Just to add a safety factor, run for less time to ensure you make it back to your start point. I run mine for no more than 40 min out and back give or take to factor in currents.
JUNI P depends at the current. this model model can run about 45 minutes nonstop you can figure out from here. it's about walking speed... I would say a half or a quarter mile should be okay.