With an underwater drone you can explore lakes and oceans like never before. You can use them for leisure, research, fish finding, hull inspection, treasure hunting, and more -- all without getting your feet wet.
We've been investigating their capabilities to help you find the right model for your needs. We've put together a concise guide, and we've also made a few recommendations. Our favorite, the Geneinno Titan, is a remarkable vehicle offering tremendous control and high-resolution imagery and is capable of going deeper than anything in its class.
Considerations when choosing underwater drones
Underwater drones are considered ROVs (remotely operated vehicles), and most, even those you see on deep-sea exploration vessels, are attached to the parent ship by an umbilical cord. When it comes to consumer models, it's usually called a tether. At one end it's attached to the drone, at the other to a control unit. Actual control is usually via a smartphone app that links to the controller by WiFi. So when you see a drone called "wireless" it's referring to communications for those functions -- it still has a tether.
The length of that tether is going to have a big impact on potential uses. If you're examining hulls in a boat yard or marina, you don't need a lot, but you'll usually get at least 90 feet. Whereas most scuba divers tend to max out at about 130 feet, the most advanced underwater drones can dive to almost 500 feet, where water pressure is over 200 pounds per square inch.
The other major factor will be image capture, and most can record 4K video, though if you're recording video for post processing, you'll want to check the frames per second rate (fps). Live streaming comes at lower resolution -- either 720 or 1,080 pixels -- but that's still perfectly adequate for viewing on your phone or social media. You'll save battery power by taking stills, which range from 8 to 16 megapixels depending on model. A few have VR headset capability, bringing an added dimension to your viewing.
Control functions vary, and in general the more thrusters you have, the better you can handle the drone in terms of depth and direction. Four will offer better stability than two, and our favorite has six, making it capable not just of pinpoint positioning, but of automatically hovering where you put it. Speed is sometimes quoted, but the best max out at around two meters per second (about 4.5 miles per hour), so it's not really a big deal.
You'll want to think about run time. Battery life depends on several factors, like how fast you're going, whether you're fighting the current, recording high-resolution video, and even the water temperature. Depending on the model, you'll get anywhere from two to six hours dive time. You might also want to look at recharge times. None of them are quick, so expect a couple hours.
Finally, lights can be useful, particularly in murky water. Some underwater drones also have sonar so they can avoid obstacles and feed topographical information back to your app.
The cheapest underwater drone we found was around $350, but range and run time are modest. We'd expect to pay around $500 for a good entry-level machine. There's plenty of choice in the $800 to $1,800 price bracket, and consumer models top out at about $3,500. Beyond that, the sky (or rather the sea) is the limit. Scientific models can cost hundreds of thousands of dollars.
Q. Why do almost all underwater drones have a tether?
A. Radio signals don't transmit through water, so you need the tether for control functions, and to receive live video. Of course it's also a handy way to retrieve your drone manually if something goes wrong.
A. There are a couple that are designed for this, but they are expensive. Also bear in mind that even experienced scuba divers seldom go beyond 130 feet. Many underwater drones can comfortably exceed that, going where you can't.
What we like: Outstanding depth capability of 492 feet. Records 4K video with up to 64GB storage, and 1,080-pixel live streaming. Six thrusters offer smart hover, holding precise depth and position in current. Four-hour run time.
What we dislike: Charging is slow. Other than that, faults are rare and support is very good.
Our take: Versatile midrange model with high-end photography and video features.
What we like: Four thrusters and a straightforward app provide good control. Records 4K video at up to 120 frames per second and takes 16-megapixel stills. Maximum depth of 328 feet. Three-hour battery life.
What we dislike: Charging can take 2.5 hours. Quite heavy at over seven pounds with battery.
Bob Beacham is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money. BestReviews never accepts free products from manufacturers and purchases every product it reviews with its own funds.
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