Submersible

A submersible is an underwater vehicle that needs to be carried and supported by a larger watercraft or platform. This makes submersibles different from submarines, which can operate on their own for long periods at sea.

There are many kinds of submersibles, including ones that people can ride in and ones that operate without a crew. These uncrewed craft are called remotely operated vehicles (ROVs) or unmanned underwater vehicles (UUVs). Submersibles are used for many important jobs, such as studying the ocean, exploring underwater ruins, discovering new parts of the sea, enjoying tours, fixing equipment, recovering lost items, and filming underwater scenes.

History

See also: Submarine § History

The first underwater vehicle that could move by itself was made in 1620 by Dutch inventor Cornelis Drebbel. It was a small submarine powered by oars. King James I may have even tried it out for himself.

Later, in 1775, American inventor David Bushnell created the first submersible used in war. Called the Turtle, it was built to place explosives on enemy ships during the American Revolutionary War. It could dive by filling tanks with water and come up by pumping the water out. The person inside used hand wheels to move up, down, or sideways underwater. Though it tried to attack a British ship in 1776, it couldn’t attach the explosive because of strong currents.

Today, such vehicles are often used by special forces for special missions.

Operation

A submersible is different from a submarine because it is not fully independent. It often needs help from a bigger boat for power and air. Most submersibles work better underwater and have little use on the surface. Some stay connected to a bigger boat using a long cord.

Submersibles are usually small and can hold only a few people. They do not have spaces to live in for long. They can move quickly underwater using special tools and may have parts that people can control to do tasks.

Technologies

Submersibles use many special tools and methods to work underwater. Some important technologies include:

• Buoyancy control
• Marine thrusters
• Pressure vessel with external pressure load
• Life support systems
• Through-water communications
• Manipulator arm
• Submarine navigation

When an object is underwater, it pushes away the water around it. This creates an upward force called buoyancy. If the object weighs more than the water it pushes away, it will sink. If it weighs the same, it will stay still. If it weighs less, it will float up.

Submersibles can change how much they weigh underwater to move up or down. They can make themselves heavier to sink or lighter to float on the surface. Some can even let water fill inside so the crew needs special breathing equipment to stay alive underwater.

Deep-diving crewed submersibles

Main article: Deep-submergence vehicle

Some special underwater vehicles can dive very deep. The bathyscaphe Trieste was the first to reach the deepest part of the ocean, almost 11 kilometers below the surface, in the Mariana Trench in 1960.

China, with its Jiaolong project, was the fifth country to send a person over 3,500 meters below sea level. In 2012, the Jiaolong submersible went down over 6,900 meters into the Pacific Ocean.

One of the most famous underwater research vehicles is the DSV Alvin, which can take three people to depths of up to 4,500 meters. It is owned by the United States Navy and operated by WHOI.

In 2012, James Cameron made a record dive to the bottom of Challenger Deep in the Mariana Trench using his submersible named Deepsea Challenger.

The DSV Limiting Factor, sold and renamed Bakunawa in 2022, holds records for the deepest dives in all five oceans. It was first used by Victor Vescovo and his organization Caladan Oceanic, and is now operated by Gabe Newell's Inkfish research group. The vehicle has helped find shipwrecks and explore deep ocean areas.

Commercial submersibles

Private companies like Triton Submarines, LLC, SEAmagine Hydrospace, Sub Aviator Systems, and Netherlands-based U-boat Worx make small submersibles for tourism, exploration, and adventure travel. In British Columbia, a company named Sportsub has been building personal recreational submersibles since 1986 with special open-floor designs.

Another private U.S. company, OceanGate, also worked on building submersibles. However, the company faced attention when their newest submersible imploded underwater.

Marine remotely operated vehicles

Main article: Remotely operated underwater vehicle

Small uncrewed submersibles, called marine remotely operated vehicles (MROVs) or remotely operated underwater vehicles (ROUVs), are used when water is too deep or dangerous for divers, or when it saves money. These vehicles help fix offshore oil platforms and attach cables to lift sunken ships. They are connected to a ship by a thick cable that gives them power and lets operators control them. People on the ship watch video or images from the vehicle and steer it using controls. Famous wrecks like the Titanic have been explored using these vehicles, along with crewed ships.

Autonomous underwater vehicles

Main article: Autonomous underwater vehicle

An autonomous underwater vehicle (AUV) is a robot that can move underwater on its own, without needing someone to control it all the time. AUVs are part of a group called unmanned underwater vehicles, which also includes vehicles that are controlled from far away by a person. In the military, these are sometimes called unmanned undersea vehicles (UUVs). Underwater gliders are a special type of AUV.

Diver lock-out submersible

A diver lock-out submersible is a special kind of underwater vehicle. It has an airlock and a built-in diving chamber. This allows underwater divers to exit and enter the submersible while it is underwater. Examples include the Deep Diver, a research submersible, and the Antipodes (submersible), a commercial submarine built in 1973.