Modern ROV systems can be categorized by size, depth capability, onboard horsepower, and whether they are all-electric or electro-hydraulic. In general, ROVs can be grouped as follows:

  • Micro - typically Micro class ROVs are very small in size and weight. Today’s Micro Class ROVs can weigh less than 3 kg. These ROVs are used as an alternative to a diver, specifically in places where a diver might not be able to physically enter such as a sewer, pipeline or small cavity.
  • Mini - typically Mini Class ROVs weigh in around 15 kg. Mini Class ROVs are also used as a diver alternative. One person may be able to transport the complete ROV system out with them on a small boat, deploy it and complete the job without outside help. Occasionally both Micro and Mini classes are referred to as "eyeball" class to differentiate them from ROVs that may be able to perform intervention tasks.
  • General - typically less than 5 HP (propulsion); occasionally small three finger manipulators grippers have been installed, such as on the very early RCV 225. These ROVUs may be able to carry a sonar unit and are usually used on light survey applications. Typically the maximum working depth is less than 1,000 metres though one has been developed to go as deep as 7,000 m.
  • Light Workclass - typically less than 50 hp (propulsion). These ROVs may be able to carry some manipulators. Their chassis may be made from polymers such as polyethylene rather than the conventional stainless steel or aluminium alloys. They typically have a maximum working depth less than 2000 m.
  • Heavy Workclass - typically less than 220 hp (propulsion) with an ability to carry at least two manipulators. They have a working depth up to 3500 m.
  • Trenching/Burial - typically more than 200 hp (propulsion) and not usually greater than 500 hp (while some do exceed that) with an ability to carry a cable laying sled and work at depths up to 6000 m in some cases.
  • Autonomous underwater vehicle (AUV) - a robot which travels underwater without requiring input from an operator. AUVs constitute part of a larger group of undersea systems known as unmanned underwater vehicles, a classification that includes non-autonomous remotely operated underwater vehicles (ROVs) – controlled and powered from the surface by an operator/pilot via an umbilical or using remote control. In military applications AUVs more often referred to simply as unmanned undersea vehicles (UUVs).



Power (hp)

Micro Observation
(<100 meters)
Low Cost Small Electric ROV


Mini Observation
(< 300 meters)
Mini (Small & #9;(Electric))


Light/Medium Work Class
(<2,000 meters)
Medium (Electro/Hyd) <100
Observation/Light Work Class
(< 3,000 meters)
High Capacity Electric


Heavy Work Class /Large Payload
(<3,000 meters)
High Capacity (Electro/Hyd)


Observation/Data Collection
(>3,000 meters)
Ultra-Deep (Electric)


Heavy Work Class /Large Payload
(>3,000 meters)
Ultra-Deep (Electro/Hyd)


Trenching and Burial Bottom Crawlers and Plows  
Towed Systems Towed Systems  
Autonomous Underwater Vehicles Untethered AUVs