If you are here, it means one thing: underwater drones have caught your attention and you want to know more about them. So what are underwater drones?
An underwater drone or ROV (remotely operated vehicle) is a remotely controlled watercraft, designed to operate underwater. Its primary function is to record underwater footage. It can also be deployed to do underwater installations surveys, scientific research in water environments or surveillance as in military operations.
If you’re open to more information, you can carry on reading below!
When was the first drone invented?
The idea of ROVs or remotely operated underwater vehicles is not new. As a matter of fact, they have been around since the 1950s for research purposes. The military took interest in this concept and created UUV (unmanned underwater vehicles), they used them in response to sea mines. They were the first responsible for the damage and destruction of naval ships more than any other type of attack.
Different industries as well took part in this revolution. For instance, oil and gas used them for underwater installations surveys and inspections. However, the amateur underwater drone market has revealed itself only recently!
What are they used for?
Underwater drones are being used for a plethora of applications. Undeniably, they will be conquering more terrain in the future years to come. For the time being, underwater ROVs are being operated in the following scopes.
This is maybe the first use of submersible ROV when they come to mind. We often picture a drone surveying the inaccessible seabed and observing bizarre sea creatures.
This technology can be used to map underwater topography and geological structures.
Like their flying cousins, underwater drones can bring a new perspective in videography. They indeed are able to film for longer periods than humanly possible and be operated in inaccessible or hazardous locations for humans. In result, this has opened and will be opening new doors for underwater filmography.
Unmanned underwater vehicles (UUV) are -to put it in simple terms- autonomous submarines used in oceanic warfare. Reconnaissance, underwater mines detection and termination, as well as marine warfare are its main functions.
Search and rescue missions:
Using the right tool can mean the difference between life and death. A ROV is particularly useful in bad weather conditions and limited visibility (murky water, night time…) for the human eye. For this particular purpose, it can be fitted with sensor systems like sonar to navigate and identify targets.
Survey of industrial facilities:
Oil and gas industry was from first adopters of underwater drone technology. For instance, it has been used to inspect drilling sites pipelines and other subsea equipment.
Monitoring the health of farmed fish has never been easier. In fact, once the drone is deployed into a net cage it can be operated much more efficiently than with human divers doing the work.
The amateur market for underwater drones is still in his infancy. Nonetheless, many have already invested in a drone as a leisure companion. It can indeed be used to film your diving or snorkeling activities as well as your fishing sessions. Depending on the model, you can be filmed by another person operating the device from the surface. In other cases, some drones can be wirelessly operated underwater. Some even have autonomous functions and you can let them film you while you enjoy your dives.
How can an underwater drone move?
The movement is created via a propeller or thruster, which is driven by a brushless motor enclosed into the frame. An underwater drone comes equipped with at least 2 propellers. From a drone model to another, the number of propellers (and motors driving them) and their power output is what changes. Drones with more freedom of movement or degrees of freedom feature more propellers. Furthermore, some manufacturers have equipped their ROVs with self-balance control systems. As a result, they’re easier to use especially during operations requiring stability like objects manipulation.
Furthermore, it is important to know that ost underwater drones can cruise at average speeds of 1.5m/s (4.9ft/s or 5.4km/h or 3.5mph) or up to 2m/s (6.5ft/s or 7.2km/h or 4.4mph) when enabled by weather conditions and water currents are ideal.
How are underwater drones operated?
Underwater drones are operated remotely. As a consequence, you’ll need to send your commands to the device. Vice versa, the drone should communicate to you the video feed as well the navigation data. This brings us to the question of how do underwater drones communicate?
The issue of underwater drones communication comes as a challenging one. Notably, water has a limited ability to carry electromagnetic signals. Therefore, wireless communication for underwater devices in general is a very tricky thing. As a result, most underwater ROVs communicate with the remote control via a wire or tether. Nonetheless, wireless communication is still possible but with some constraints.
Here are the 3 possible ways of communication with some details.
- Tethered: the drone is attached to a tether which acts as a channel to transfer data between ROV controller and the submersed device.
- Advantages: ability to cover wide areas.
- Inconvenients: Depth range is limited by tether length. Tether cable can also create additional drag especially in strong currents.
- Wireless: No tether is needed, but the user should be near the drone. Usually the ROV can be operated underwater as long as in range (usually 10m/30 ft range)
- Advantages: wireless drones possess a certain level of autonomy, obstacles avoidance is a feature on some of them, gives some freedom to the drone operator.
- Inconvenients: very short range of use.
- Tethered and wireless: A communication buoy is attached by an umbilical cable to the drone. The buoy conveys the remote controller signals to the drone. Vice versa, the latter conveys video feed and other data to the buoy who transfers it to the user screen.
- Advantages: less tether physical constraints .
- Inconvenients: wireless signals need to be reliable enough for optimal performance.
That being said, you’ll be able to understand the maximum range and maximum depth a drone can reach.
Depth and horizontal range:
Commercially available underwater drones feature a wide range of capabilities. They can go as deep as 15m/49ft for the most basic ones, to 305m/1000ft for more premium drones. Naturally, diving deeper means the device should resist crushing pressures. This explains partially the correlation between how deep a drone can dive and its purchase prices.