The Truth About Underwater Robots: How Do They Work?

Like space, there are many parts of the water bodies on the Earth that have not yet been explored due to the complicated environment which makes it difficult for humans to survive. 

This is where underwater robots come in. They have been designed to endure the harshest elements of the underwater environment while performing a variety of practical application tasks.

These submersible robots are used to explore the underwater environment. 

Although curiosity about what lies beneath thousands of feet of water is also a driving factor, one of the main reasons robots are sent to explore the oceans is to confirm the availability of resources like oil, gas, and metals

Another reason for sending robots underwater is to find if infrastructure such as bridges and dams pipes can be built. 

Deep-sea exploration is also critical for both military and communication infrastructures. 

The rapid advancement in technology and AI has allowed robots to perceive the environment while avoiding obstacles and navigating autonomously. 

Thus, they are more than capable of exploring marine life with minimum input from operators. 

Underwater robots are used for researching marine life, exploring the depths of the ocean to find any natural resources, and helping lay infrastructure for communication and military purposes.

What Are Underwater Robots?

Before we move on to explaining what underwater robots do, lets take a look at what exactly underwater robots are, to bring things a little into perspective.

Underwater robots, pretty much like other robots, are a combination of powerful programming, high-quality machine parts, and AI. 

Over the years, they have become an essential tool for ocean exploration. 

These robots can be programmed to go to remote, unexplored and potentially dangerous parts of the ocean to collect samples and send back pictures of what lies there. 

Each underwater robot is manufactured to perform a different task. While some take samples to check the salinity and temperature of the area being explored, others measure the speed of the currents or map the seafloor. 

The Tech Behind Underwater Robots

To ensure that underwater robots survive the harsh environmental conditions of the oceans and send back viable information, special robot sensing technology has to be used. 

This technology is playing a crucial role in the advancement of robotics as well as in the success of robotic expeditions. 

One of the main pieces of tech used in underwater robots is acoustic ranging/imaging sensors. 

These sensors help the robot in computing its depth underwater, its position according to nearby objects and help it avoid obstacles. 

The acoustic sensors employed in underwater robots use sonar which also helps in acquiring near and long-distance acoustic images. They can also be used to obtain images that undergo 3D reconstruction. 

Other tech commonly used in underwater robots includes video and imaging cameras, propulsion systems to help the robot navigate, and lights. 

Apart from this, specialized equipment is also installed depending on the objectives of the robotic mission. 

These include: 

  • Manipulator arm
  • Water sampler
  • Instruments that measure clarity
  • Instruments that measure light penetration
  • Temperature sensors
  • Depth sensors
  • Compass
  • Inertial measurement unit

Different Kinds of Underwater Robots

As mentioned, each robot is manufactured based on specific requirements, depending on the type of mission it will have to complete. 

Hence, over the past few years, several different types of underwater robots have emerged. 

Some of the most commonly used underwater robots are:

Unmanned Underwater Vehicles

UUVs are manufactured to map large areas of the sea bed for the installation of military or communication infrastructure. They only move in one direction. 

Remotely Operated Vehicles

These are omnidirectional underwater robots that are controlled by operators aboard a ship or a station.

They are connected to a tether and are externally powered. ROVs are usually used to inspect offshore structures. 

Autonomous Underwater Vehicles

AUVs are untethered robots that maneuver in all directions on their own. They have grasping and manipulation capabilities which means they can collect samples and send data. 

Low-Cost Vehicles

These are usually used by the general public, hobbyists, or college students who are researching certain elements of the sea. 

Different Kinds of ROVs

ROVs or Remotely Operated Vehicles are the most commonly used type of underwater robots. 

They are further divided into different categories based on their size, the depths they can reach, and their power. The categories they are divided in are as follows:

Micro-class ROVs

As the name suggests, these ROVs are small in size and do not weigh a lot. 

In most cases, they weigh less than 3 kgs and are used to access areas that divers cannot due to physical limitations. 

These areas might include small trenches, cavities, sewers or pipelines. 

Mini-class ROVs

Mini ROVs can weigh up to 15 kgs and are also used as an alternative to human divers. 

They are usually manufactured to complete a diver’s job without any external help. 

General ROVs

General ROVs have are a rate of less than 5 horsepower. 

They are equipped with manipulators, grippers, a sonar unit and can go up to 1000 meters deep into the water.

Light Work Class ROVs

These robots are rated at less than 50 horsepower and are manufactured using polymers instead of conventional alloys. 

They can go to depths of up to 2000 meters. 

Heavy Work Class ROVs

Rated at 220 horsepower, heavy work ROVs can carry two manipulators and go up to 3500 meters deep.

Trenching/Burial ROVs

These ROVs have up to 500 horsepower and can go work at depths up to 6000 m in some cases.

Researching Marine Life

Underwater robots play a crucial role in several military and commercial tasks. However, they are extremely important for researching marine life as well. 

Thanks to these robots, sampling and other intervention tasks have become easier and more convenient. 

The goal of these robots is not to ultimately replace human divers. Rather, the scientific industry is working to develop a generation of subsea equipment that can sustain itself on its own while sending data back. 

Recently, a group of students sent some torpedo-shaped bots into spinning columns of water. 

Since the spinning of water brings deep-sea sediments and nutrients to the surface, they were hoping to collect microbial life. 

Underwater microbial life is important to understanding marine life. However, it is challenging to study. 

Human divers cannot go into eddies and to the sea bed to collect samples. That is where underwater robots come in. 

This curiosity about what lies beneath all this water on Earth has led to the development of several underwater robots that are working to help humans discover new organisms and species. 

Exploring Uncharted Marine Territory Safely

Underwater robots can go to the murky depths of the sea without having to worry about their oxygen ending or dealing with narcosis due to the water pressure. 

Scientists can explore uncharted marine territory and gather data without risking human lives. 

Water bodies cover more than 70% of the Earth’s surface. However, due to certain physical limitations, only 20% of the waters have been explored. 

Scientists even claim that they know more about Mars than they do about Earth’s ocean floor. 

Hence, using underwater robots is the best way to probe the limits of life on Earth. 

Marine biologists have sent multiple robots equipped with the necessary sensors and cameras to the unchartered marine territory. One of these areas is the hadal zone.

Underwater Mining

The ocean bed is home to unexplored and naturally occurring metallic nodules. These nodules can be used to extract several rare Earth metals.

The demand for these materials is soaring mainly because of the increased use of electric vehicles and wind turbines. 

However, collecting metallic nodules from the ocean floor can be dangerous for human divers. This is where underwater robots come into play. 

Recently, a team of researchers from Canada spotted a 1.7-million-square-mile patch of oceanbed where metallic nodules exist. 

They sent a group of box-shaped bots equipped with coring devices into the ocean to extract them. 

In addition to extracting the nodules, the robots also bring up sediments from the ocean floor for research purposes.  

Surveying the Ocean Floor

As mentioned, mapping the ocean and seafloor is crucial for laying communication and military infrastructure. 

ROVs can survey the ocean floor and perform the required inspection to declare a particular part of the ocean or sea floor fit for installing the pipelines. 

They can also help in investigating and analyzing shipwrecks and cultural sites underwater. 

Some of the mapping tasks carried out by underwater robos include:

  • Bathymetry
  • Sonar imaging
  • Magnetic field mapping
  • Hydrothermal vent localization
  • Photo surveys

Collecting Research Data Year Round

ROVs and AUVs can help scientists collect data from locations that are inaccessible to human divers. These also include places under ice shelves. 

In addition to this, they can also collect data during the winter season or the season when currents are faster than normal. 

It is almost impossible for human divers to go underwater during the heavy current and Eddie season. 

Robots with high propulsion power can easily maneuver underwater even if the currents are strong or they find themselves stuck in a whirlpool.

One such example is the Mayflower Autonomous Research Ship which is designed to collect limitless data points.

Waves as an Alternate Source of Clean Renewable Energy

Oceans and seas have waves underwater as well. These waves are stronger and more powerful than the ones we see on the surface. 

Since 70% of the planet is covered in water, there is no cleaner way of producing energy than harnessing wave energy. 

This will not only make the process of energy production more environmentally friendly but will also decrease our depending on fossil fuels. 

Scientists are working on developing tech that is akin to windmills for waves. 

Some private companies have even designed paddleboards and rafts that harnesses the waves on the surface of an ocean or sea to produce electricity. 

Underwater robots can be used to deploy this tech on the ocean or seafloor. 

Cleaning Up the Oceans

Over the years, our oceans have become waste bins for the world. This has led to the severe deterioration of marine life. 

In addition to performing underwater surveys and deploying tech, underwater robots can also help us clean up the oceans to provide a better environment for marine life. 

Ocean surfaces, especially harbors are laden with waste such as plastic bags, balloons, and more. 

Underwater robots are being designed to clean up the debris on the ocean surface as well as the debris that has made its way underwater. 

Two such robots have already been deployed around the coast of Dubrovnik, Croatia to test their viability. They maneuver on the surface as well as underwater looking for garbage. 

Contemporary Underwater Robot Companies

Scientists and engineers are working together to design underwater robots that can help with several expeditions that are almost impossible for humans. 

Some of these contemporary robots that are being designed are:


OceanOne is a Robo-mermaid diving robot designed by computer scientists at the University of Stanford. 

The robot explores deepwater vessels to collect samples. It can be controlled using a joystick. 


The BIOSwimmer is a creation of Boston Engineering. It is a tuna-shaped robot that blends with the sea life to explore their behavior patterns. 

Curious Robots

Designed by a research team at Woods Hole Oceanographic Institution, the curious robot dives into the ocean with human divers and takes pictures of the objects it finds interesting. 

What Does the Future Hold for Underwater Robots?

The world of underwater robots is expanding rapidly. Engineers and scientists are coming up with new concepts and new designs for robots that can explore sea life and provide the means of exploring unexplored areas.

One of the concepts that are being widely adopted is ‘swarming’. It includes manufacturer relatively smaller and low-cost robots that can be deployed in a group. 

This way, a larger area can be covered in less time. They will be created using inexpensive sensors and control systems. Since, if one or two of them start malfunctioning, the rest of the group will still keep sending data back. 


Underwater robots and robots that are sent to space are pretty much the same. 

The only difference is that space robots are designed to endure lift-offs while underwater robots are manufactured to deal with high underwater pressure. 

Hence, most underwater robots are manufactured the same way as space robots. 

Currently, NASA is working on a new autonomous underwater vehicle called Orpheus. 

The AUV uses the same technology as Nasa’s Perseverance Mars Rover. 

This new robot will use highly sensitive cameras to identify and analyze rock formations, shells, and other features. 

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Frequently Asked Questions

What can underwater robots do?

Underwater robots perform surveys, collect data and deploy underwater infrastructures. 

Do robots need to breathe?

No, robots do not need to breathe.

How long can a robot stay underwater?

This depends on the type of technology and the machine parts used. 

What sensors do underwater robots have?

Underwater robots have GPS, compass, video and imaging cameras, sonar, temperature sensors, and more. 

Can robots be waterproof?

Yes, underwater robots are waterproof.