Picture yourself standing on a jetty at a lake, phone in hand, and seeing live what lies on the bottom ten metres below you. That is exactly what an underwater drone makes possible. You need no diving certificate and no wetsuit, just a bit of curiosity. In this guide we explain, step by step, what such a device is, how it works and what it is good for as a hobby.
- An underwater drone is a small, remote-controlled submersible with a camera.
- Professionals call it an ROV, short for “Remotely Operated Vehicle”.
- It hangs on a tether because radio barely gets through underwater.
- It is usually controlled with a remote control and your own smartphone.
ROV, underwater drone, diving robot: what is what?
Don't worry, they all mean the same thing. “ROV” is the technical term from the professional world, where such devices inspect ship hulls or harbour walls, for example. For leisure use, the term “underwater drone” has caught on in the German-speaking region, borrowed from the familiar flying drones. The big difference: a flying drone flies freely by radio, while an underwater drone always stays connected to you by a thin tether.
How an underwater drone works
Water absorbs radio waves almost completely. That is why control commands and the video picture travel along a cable that specialists call a “tether”. The interplay looks like this:
The drone itself has several small propellers (thrusters) that let it move forwards, sideways, up and down. At the front sit a camera and bright LED lights, because even a few metres below the surface, local lakes quickly become dark and murky. The power comes from a battery in the drone.
What can I do with one as a hobbyist?
- Explore a swimming lake: Watch fish, water plants and sunken tree trunks up close.
- Fishing: See where the fish actually are and what the bottom is like.
- Boat and mooring: Check the anchor, chain or hull without jumping into the cold water yourself.
- Holiday videos: Shoot underwater footage by the sea in Croatia or Italy that only divers usually see.
- Small search jobs: Find out where the sunglasses that fell in the water ended up. Some models even have a gripper arm for this.
Where am I allowed to dive it?
We have not found a separate licence or registration requirement for underwater drones in Germany, Austria or Switzerland. As we understand it, the familiar drone rules only apply to aircraft. Even so, not every body of water is freely accessible: bans can apply in nature reserves, harbours, shipping lanes, private ponds or supervised bathing beaches. If in doubt, ask the owner of the water, the local council, whoever holds the fishing rights or the harbour authority. And if people come into the picture, the usual rule applies: ask first, then film.
What does an underwater drone cost?
Chasing's simplest model, the Dory, costs around US$600 in the official shop, but is hardly available any more from dealers in the German-speaking region. Well-equipped hobby drones with a 100-metre tether and a 4K camera, such as the Chasing Gladius Mini S or the FIFISH V-EVO, cost roughly €1,300 to €1,800. There is plenty of room at the top: models with more light, a swappable battery and professional accessories cost €3,000 and more.
In video
The manufacturer CHASING explains briefly what an ROV is, and introduces its entry-level drone, the Dory.
Frequently asked questions
What is the difference between an ROV and an underwater drone?
There is none. “ROV” stands for “Remotely Operated Vehicle” and is the technical term from the professional world. In the hobby sector, the word underwater drone has caught on in the German-speaking region.
Why does an underwater drone have a tether?
Water absorbs radio waves almost completely. That is why control commands and the video picture travel along a cable that specialists call a tether.
Do I need a licence or a registration?
We found no separate licence or registration requirement for underwater drones in Germany, Austria or Switzerland. As we understand it, the familiar drone rules only apply to aircraft. Even so, bans can apply in nature reserves, harbours, shipping lanes, private ponds or supervised bathing beaches. This is not legal advice.
What does an underwater drone cost?
The basic Chasing Dory costs around US$600 in the manufacturer's shop. Well-equipped hobby drones with a 100-metre tether and a 4K camera, such as the Chasing Gladius Mini S or the FIFISH V-EVO, cost roughly €1,300 to €1,800. Models with more light, a swappable battery and professional accessories cost €3,000 and more.
What can I do with an underwater drone as a hobbyist?
You can explore swimming lakes, check where the fish are when fishing, inspect your boat's anchor and hull, shoot underwater holiday videos and look for things that have fallen into the water on small search jobs.
Make your first dive at a calm, clear lake close to the shore and let out only a few metres of tether at first. That way you learn the controls without the tether snagging on branches or stones. And after every outing in salt water, rinse the drone thoroughly with fresh water.
You can find reactions and comments on this article in the Unterwasserpilot forum (in German, English posts welcome).
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