What Is an Underwater ROV and How Does It Work?

An underwater ROV (remotely operated vehicle) is an uncrewed, tethered submersible that an operator pilots from a surface vessel or control room. It carries thrusters, cameras, sensors and often manipulators, and it receives power and commands through an umbilical cable. Electric ROVs, such as those built by Saab Seaeye, are used for inspection, maintenance and intervention across offshore energy, telecoms, salvage, aquaculture, marine science and defence work. The sections below explain the main components, how piloting works, typical missions, and where electric systems fit best.

ROV vs. AUV: the key difference

Both are uncrewed underwater vehicles, but they operate differently:

A hybrid vehicle combines elements of both, and Saab Seaeye describes its range as including tethered, autonomous and hybrid electric robotic systems.

The main parts of a tethered electric ROV

• Thrusters — electric motors driving propellers for forward, lateral and vertical movement. Because they are electric, they avoid the hydraulic fluid and plumbing that hydraulic systems require.
• Manipulators and tooling — hydraulic or electric arms and specialist subsea tooling let the vehicle grasp, cut, clean or turn valves rather than only observe.
• Sensors and cameras — video, sonar and positioning sensors give the operator a view of the work site and the vehicle's location.
• Umbilical cable — delivers power and carries command and video signals between the vehicle and the surface.
• Deployment and control systems — launch and recovery equipment, plus control cabins where the pilot sits.

How an operator pilots an ROV

1. The vehicle is launched from a vessel or platform and connected to its umbilical.
2. The pilot watches live camera and sensor feeds at the control console.
3. The pilot sends movement and tool commands down the cable; the thrusters and manipulators respond.
4. The pilot uses the video feedback to position the vehicle and complete the task, adjusting as conditions change.

The practical result is that a human stays in the loop for the whole dive, which suits tasks where judgment matters — inspecting a damaged structure, for example, or operating a tool at a precise point.

What ROVs are used for

Saab Seaeye lists sectors that show the breadth of real missions:

• Oil and gas — inspection, maintenance and intervention on subsea infrastructure
• Renewables — offshore wind and related marine energy work
• Telecoms — subsea cable routes
• Salvage — locating and working on wrecks and lost equipment
• Hydro and civil engineering — dams, intakes and marine structures
• Aquaculture — net and cage inspection
• Marine science and academia — research observation and sampling support
• Seabed minerals, nuclear, leisure and tourism, civil security and emergency response, and military and defence

For a reader deciding whether an ROV fits a task, the useful test is whether the job needs live human judgment at a specific underwater location. If it does, an ROV is the natural tool; if it is a broad survey with no interaction, an AUV may be more efficient.

Electric vs. hydraulic: advantages and limits

Electric ROVs are attractive because they avoid hydraulic fluid, which reduces leak risk and simplifies maintenance, and Saab Seaeye frames its technology as eco-responsible. Electric thrusters also tend to give fine, responsive control for close work.

The limits are equally practical. A tethered ROV's reach and maneuverability are constrained by its umbilical, and heavy intervention tasks may still call for hydraulic manipulators or tooling. The right choice depends on the mission: light inspection and precise electric control favor an electric vehicle, while high-force work may need hydraulic capability.

Where to go next

Saab Seaeye's site organizes its offering by sector and by solution — underwater vehicles, electric manipulators, deployment systems, control cabins, defence vehicles and Hydro-Lek tooling — with product support, after-sales support and training under Support. If you are scoping a project, start from the sector closest to your mission and then check which vehicle and tooling combination matches the depth, task and intervention force you need.